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Service and Repair Manual

1. clutch thrust NA plate 71 clutch plate fixed 77 friction discs 78 a s age clutch plate 2 loose 79A P Ilustration B 5 Section B Remove the locking wire from the 4 special bolts 73 and so remove these bolts The individual components may now be removed in the following order Clutch thrust plate 71 distance pieces 75 and springs 76 clutch piate fixed 77 disc 78 2 friction discs and 1 loose plate 79A if of the double plate version and lastly the bottom loose plate 79 TO ASSEMBLE THE CLUTCH UNIT refer to illustration B 4 unless otherwise stated Assembly of the clutch unit is the reverse of the dismantling procedure When fitting the friction disc s check that the plates are central Fit the 4 special bolts 73 and tighten evenly to a torque of 31 Ibs ft 4 2 kg m Secure the special bolts using a new piece of 12 long 16 swg locking wire TO FIT THE CLUTCH UNIT See instruction 5 TO REMOVE THE CLUTCH SHAFT Special note It is not necessary to dismantle the gearbox in order to remove the clutch shaft or the driving pinion provided the shaft is not broken inside the gearbox In cases where the shaft is broken at a point behind the thread a clutch shaft puller special too S 1 see section A will be required Alternatively it may be possible to weld a stud onto the front of the shaft so that the same method of removal may be used as for an
2. CONTENTS SERVICE BULLETINS APPERTAINING TO THIS SECTION ARE TOOLS LIST Subject BACKPLATE CHAIN CHAIN TENSIONER CHAIN CASE JACKSHAFT JACKSHAFT SPROCKET ROTOR ASSEMBLY ROTOR CLUTCH ROTOR DRIVE SHAFT SPROCKET ROTOR STUB AXLE Action Assemble Dismantle Fitting Removal Adjustment Fitting Removal Fitting Removal Fitting Removal Fitting Removal Fitting Removal Adjustment Assemble Dismantle Fitting Removal Fitting Removal Fitting Removal No off 4 BSW Ring spanner 3 BSW Ring spanner 2 BSW Ring spanner is BSW Ring spanner 3 BSW Ring spanner 4 BSW Ring spanner Cold chisel Copper Rawhide mallet Pair 6 engineers pliers Medium screwdriver sech ee m m mm mm sesch mb BSW Open ended spanner i BSW Open ended spanner Seciion F Section F BLADES If blades are to be replaced check that the new blades are of the correct form i e left or right handed On the centre flange s the blades should be fitted to the left hand side with the bolt heads against the blade shank and the spring washers and nuts against the flange The end blades should be fitted on the inside of the flanges using the special bolts F7 219 with the spring washers and nuts against the blade shank For further information on blades see blade maintenance Section G TO REMOVE THE ROTOR ASSEMBLY refer to illustration F7 on pa
3. ENGINE CLUTCH Single plate heavy duty dry friction plate CONTROLS All situated within easy reach of the operator and are as follows 1 Clutch lever 2 Throttle lever 3 Gear lever with spring out safety device when using reverse gear 4 Handlebars adjustable for height and side swing 5 Rotor selector and differential lock control 6 Depth setting lever ROTOR Rotor speed 188 rpm at an engine speed of 2800 rpm Rotor widths of 20 51 cm 24 61 cm and 30 76 cm Tillage depth is adjustable down to 9 23 cm WHEELS 20 overall diameter using 4 00 x 12 2 ply pneurnatic tyres Tyre pressure is 20 Ib in2 1 4 kg em2 LANDSPEEDS At 2800 rpm engine speed Ist gear 0 96 mph 1 4 kph 2nd gear 1 46 mph 2 3 kph 3rd gear 3 05 mph 4 9 kph Reverse 1 85mph 2 9 kph The above landspeeds refer to machines built after serial number 250A1021 only These machines are the current production model fitted with either the Kohler K 301T K341T or the Hatz ES 780U E785 engines and the latest 36 7 ratio crownwheel and pinion See the crown wheel and pinion history in section B Section A Specifications WEIGHT Petrol model Diesel model 20 644 Ibs 292 kg 652 Ibs 296 kg 24 672 Ibs 305 kg 674 Ibs 306 kg 30 790 Ibs 358 kg SUPER GEM Petrol mode Diesel model 24 630 Ibs dead weights 746 Ibs 338 kg 30 862 Ibs 391 kg RECOMMENDED
4. so that the differential lock assembly may be removed TO DISMANTLE THE DIFFERENTIAL LOCK Remove the locking wire 105 from the setscrews 104 and remove these setscrews NOTE The differential lock assembly will fall apart on removal of these setscrews and care should be taken to avoid losing the 3 spacers 106 22 Section C Illustration C4 universal bearing puller TO ASSEMBLE THE DIFFERENTIAL LOCK Insert the 3 differential lock pins 107 through the ring 103 and while holding the differential pins to prevent them falling out invert the ring and pass the setscrews 104 through the ring from the opposite side to the pin heads Position one spacer 106 over each threaded hole in the differential lock 108 and while holding the ring 103 in position over the differential lock screw the setscrews through the spacers and into the differential lock Fully tighten the setscrews and secure using a 9 long piece of 16 SWG locking wire TO DISMANTLE THE DIFFERENTIAL ASSEMBLY Remove the split pins 93 and the special nuts 92 from the pinion studs 99 and using a piece of wood lever the differential plate from the studs as shown in illustration C5 Remove all 6 differential pinions 97 and the loose hub gear 96 from the axle illustration C5 pinion studs 99 BENE 00 i EE bullwheel 98 23 Section C Illustration C6 If the loose hub g
5. HATZ ENGINE Place the drive adaptor against the engine flywheel and secure in position using the 6 setscrews 614 and spring washers 615 TO FIT THE BELL HOUSING 616 HATZ ENGINE With the drive adaptor in position locate the bell housing against the engine so that the 2 bolts 622 are positioned at the top Secure the bell housing using these 2 bolts 622 and the 10 setscrews 620 TO REMOVE THE ENGINE CLUTCH 2 Remove the engine as described in instruction 1 then proceed as follows 2a Remove the split pin from the end of the clutch shaft and while restraining the clutch using a flat bladed screwdriver as shown in illustration B3 remove the special nut from the end of the clutch shaft Illustration B 3 2 KA Section B Section B 2b Remove the spacer fitted to double plate clutches only and hence remove the clutch plate assembly by holding the clutch operating arm back in the disengaged position and using a soft headed hammer tap the end of the shaft This will release the clutch assembly from the splines on the clutch shaft TO DISMANTLE THE CLUTCH UNIT Refer to illustration B4 unless otherwise stated If possible mount the clutch unit on an old drive adaptor which should be clamped upright in a vice as shown in illujstration B5 as it will make dismantling easier Illustration BA distance pieces 75 clutch plate loose 79 springs 76 _
6. Fit the stay rod 373 between the main frame and the rear bracket and adjust its length using the 2 locknuts 374 such that there is approx 3 free movement between the end of the contro tube 389 and the main frame Check that the brass universal joint 395 slides freely on the 3rd reverse gear selector arm 396 and on the control rod 390 If not the location holes should be reamed out as necessary to produce free movement Locate the selector arm through the universal joint and position the control rod through the other location hole Position the selector arm over the gearbox selector shaft and locating on key 394 tap the selector arm onto the shaft and tighten the sefector arm setscrew 393 ADJUSTMENTS SHOULD BE MADE AS DESCRIBED AT THE END OF THIS SECTION REVERSE INTERLOCK MECHANISM To remove the reverse interlock Remove the nut and setscrew 451 from the base of the interlock vertical link 453 and remove the link Remove the split pins 450 from both ends of the rocker pin 449 Withdraw the rocker pin and remove the rocker 448 Remove the nut 457 and flat washer from the rod 454 and remove the spring flat washer and rod To fit the reverse interlock Position the rocker 448 between its location points in the main frame such that the lever part locates under the reverse gear selector arm 396 Slide the rocker pin 449 through the rocker and main frame and secure either end using a split pi
7. Howard Gem Howard Gem de HOWARD Service Manual INTRODUCTION This service manual has been compiled to give HOWARD Dealers and their staff a sequence of operations to enable the servicing and repair of a HOWARD GEM ROTAVATOR to be carried out quickly and effectively Because of our policy of continuous improvement this manual should always be used in conjunction with the latest service bulletins covering the GEM These service bulletins are distributed to all HOWARD horticultural dealers when they are first printed and back issues are available from us on request HOWARD GEM service bulletins after bulletin H 63 should be kept with this manual and a note added to the index of each section affected so that an up to date record of modifications is kept At the start of each section there is a list of ordinary workshop tools that will be required when carrying out the repairs covered by that section Some special tools may also be required of which a complete list can be found under special tools section A In addition to the special tools and equipment used during some repairs a hydraulic or hand operated fly press of the type found in most workshops will be required when removing and fitting oilseals and bearings Before assembly of component parts remove dirt and grease and in the case of new parts remove the special rust inhibitor otherwise the function of the component may be restricted when in opera
8. burr the lip of the bearing housing over the washer in 3 or 4 places 9 Section B TO REMOVE THE BELL HOUSING 556 KOHLER ENGINE Having removed the drive adaptor as previously described remove the 4 setscrews 560 and spring washers 561 from inside the bell housing thus allowing the bell housing to be removed from the engine TO FIT THE BELL HOUSING 556 KOHLER ENGINE Position the bell housing against the engine crankcase with the plug hole to the left and secure using the 4 setscrews 560 and spring washers 561 located inside the housing TO FIT THE DRIVE ADAPTOR 551 KOHLER ENGINE With the clutch bell housing in position slide the spacer when fitted onto the engine crankshaft and up to the engine casing Position the locating key 555 in the slot in the engine crankshaft and slide the drive adaptor into position Using an extended 2 square box spanner through the hole in the side of the bell housing tighten the square headed setscrew which secures the drive adaptor to the engine crankshaft Replace the plug in the side of the bell housing TO REMOVE THE HATZ ENGINE 1 Refer to illustration B2 unless otherwise stated la Disconnect the large fuel pipe from the injection pump on the engine NOTE Once this fuel line is disconnected the fuel in the tank will drain out due to gravity and suitable precautions should be taken ILLUSTRATION B2 SUPPLIED WITH HATZ EN
9. 27 Section C Illustration C11 Illustration C12 TO DISMANTLE REMOVE THE JACKSHAFT 8 Remove the engine and engine clutch see section B wheels and hubs gearbox cover wheel axle assembly layshaft assembly and clutch shaft then proceed as follows 8a Remove the bolts 160 which secure the rotor dog clutch selector housing to the jackshaft housing shown in illustration C13 and move the selector housing aside Hiustratron C137 ee w securing bolts 160 28 Section C 8b Remove the starter dog bearing 18 from the end of the jackshaft 12 and remove the special circlip 8c Slacken the retaining screw on the reverse gear selector arm shown in illustration C14 and remove the arm and joint block taking care to retain the locating key Illustration C14 w retainin speed change selector arm 8d Remove the selector bush 3A and withdraw from the gearbox the reverse selector together with the single pinion 17 NOTE Shims may be fitted to the reverse selector if so they should be retained as they may be required on assembly 8e Slacken the speed change selector arm retaining screw shown in illustration C14 and remove the arm and joint block taking care to retain the locating key 8f Remove the selector bush 3 and slide the double pinion 16 from the jackshaft together with the speed change selector NOTE Shims may
10. F TO REMOVE DISMANTLE THE ROTOR CLUTCH refer to illustration F6 on page TO REMOVE 60 unless otherwise stated wise stated 2 Remove the rotor assembly as previously described in instruction 1 then proceed as follows 2a Remove the wearing plate 212 and take out the split pin 208 from the special nut 207 2b Remove the oil plug 180 from the chaincase and insert a thin bladed screw driver through the oil hole and into the links of the drive chain to prevent the rotor drive sprocket 202 from rotating while removing the special nut 207 and flat washer 206 2c Slide the rotor disc 211 from the splines on the drive shaft and remove the drive plate 209 Rotor drive disc 211 The friction discs 210 are bonded to the rotor drive disc 211 by an Amyl Acetate glue If these friction discs are to be replaced the old discs must be removed completely to provide a dirt and grease free surface The glue should be applied as specified by the manufacturer see special equipment Section AT to the rotor drive disc and the friction discs positioned and clamped to it for approx 24 hours while the glue hardens Alternatively the complete assembly may be obtained as a replacement Drive plate 209 The studs 213 are simply screwed into the plate and can be removed quite easily using two locknuts clamped togethe or by using a self grip wrench on the unthreaded portion of the stud To fit
11. Fit the outer dust cover 347 and locate the axle through the arm 342 Fit the tab washer 346 and locknut 345 tighten the nut and secure by bending over the tab washer Fit and tighten the wheel cap 353 Remove oil screw 351 and lubricate bush replace oil screw To fit the rear shield see instruction 6 THE FRONT SHIELD 324 2 Remove the rear shield as previously described in instruction 1 then proceed as follows 2a Remove the 3 setscrews 184 shown in illustration EI to the right of the chaincase oil filler plug 180 and also remove the setscrew 187 which secures the shield to the top of the backplate 2b Remove the 5 setscrews 312 washers and nuts from the sideframe 295 2c Remove the rotor clutch nuts and springs 2d Undo the tab washer which secures the rotor stub axle nut to the side frame and remove the nut and tab washer 2e Remove the locking wire 297 from the 2 frame bolts 296 which secure the side frame 295 to the main frame and while supporting the rotor assembly on blocks etc remove these bolts and the side frame 46 Section E Illustration EI setscrew 187 setscrew 184 Ki 2f Slide the front shield 324 as far to the right as possible so that the rotor assembly may be withdrawn from the clutch drive plate studs complete with the outer dust cover 5 2g Remove the front shield by lifting straight out from the
12. If loose replace the joint blocks Check that the 3rd reverse gear control rod D1 390 is free to move inside the 1st 2nd gear control tube D 1 389 if not free and lubricate Support the machine such that the wheels are clear of the ground and secure the engine clutch in the disengaged position To adjust 1st 2nd gear controls while turning over the gearbox internals by means of the starting handle adjust to give neutral at the mid gate position by bending the control tube rod if necessary Check that 1st 2nd gears are obtainable and that they engage fully To adjust 3rd reverse gear control while turning over the gearbox internals by means of the starting handle adjust to give neutral at the mid gate position by screwing in or out the control rod D1 390 Check that 3rd reverse gears are obtainable and that they engage fully Check that the selector arm interlocks are not bent and that they function correctly i e that two gears cannot be selected at the same time Check that the selector arm securing setscrews are tight then lower the machine to the ground and release the engine clutch To adjust the reverse interlock Lift the clutch hand lever and select reverse gear The interlock vertical link should rise and prevent the hand lever from returning to the engaged position If the vertical link is worn replace Press down on the hand lever and check that the clutch engages adjust the length of the spring 456 a
13. LUBRICANTS Gearbox and chaincase SAE 90 gear oil all others oiling points use engine oil TORQUE LOADINGS All nuts and bolts must be kept tight and as a guide the following table of torque loadings may help In the absence of a suitable torque wrench spanners of the length specified in the right hand column of the table below will if used to maximum effect by the average man give comparable loadings Thread size Torque loading Spanner length Ibs ft kg m inches cms 1 BSW 8 5 1 2 5 12 5 2 BSW 17 5 2 4 6 15 3 BSW amp UNC 31 4 2 7 17 5 BSW amp UNC 49 6 6 8 8 20 3 BSW 8 UNC 73 2 10 10 20 3 BSW 131 9 18 1 18 45 1 BSF 9 5 1 3 5 12 5 2 BSF 19 2 6 6 15 oe BSF 54 7 7 5 8 20 3 BSF 81 2 11 1 10 25 BSF 163 22 3 18 45 e BSF 283 38 8 36 91 5 Blade bolt and nut 90 2 12 4 12 30 SPECIAL EQUIPMENT HERMATITE is a sealing compound used where specified to prevent the possibility of oil leaks Manufactured by Kenilworth Manufacturing Co Ltd Hermatite Works West Drayton Middlesex ENGLAND SAMPSON C 110 GLUE is an Amyl Acetate glue used where specified to secure the fibre discs to the rotor clutch drive discs Manufactured by Samuel Jones amp Co Ltd Sampson Adhesive Mill St Neots Huntingdonshire ENGLAND Section A Special Tools SPECIAL TOOLS The following special tools will be required when carrying out certain repairs and as they are simple
14. STUB AXLE RECOMMENDED LUBRICANTS EVERY IO HOURS d ry GEARBOX AND CRAIN CASE SAE 90 CHECK FOR BENT BLADES AND EVERY 25 HOURS BLADE BOLT TIGHTNESS RGTOR DOG CLUTCH ADJUST F NECESSARY DEPTH CONTROL WHEEL Dr FITTED CHECK ENGINE OIL LEVEL DRAIN AND RE FILL ENGINE SUMP CHECK WEED CUTTER BLADES ROTDR STUB AXLE SUSE ENGINE OIL E uolas Section G PERIODIC MAINTENANCE Every 10 hrs or DAILY 1 Check the engine oil level see engine manufacturers handbook 2 Check the level and condition of the air cleaner oil Wash out with paraffin or kerosene and refill with fresh oil if necessary 3 Check the tightness of the blade bolts and replace any bent blades 4 Watch for signs of excessive rotor clutch slip Adjust if necessary on the four spring loaded clutch nuts on the left hand end flange of the rotor For normal setting tighten the nuts to fully compress the springs then slacken back each nut half a turn EVERY 25 hrs OR WEEKLY Additional to 10 hrs maintenance 1 Service the engine see engine manufacturers handbook 2 Check the gearbox oil level 3 Check the chaincase oil level 4 Check the drive chain tension see section F adjustments 5 Oil the rotor dog clutch 6 Oil the rotor stub axle bearing 7 Ou all the pivot points hinges and other oiling points 8 Check the engine clutch adjustment and reset if necessary see section B adjustments 9 Remove and clean out the sediment
15. arm 280 Fit the handlebars 261 and secure using the special nut 271 and split pin Fit ard tighten the handlebar slide bolts 264 Locate the depth skid socket 278 and secure the support stays to the main frame staytube using the setscrews 291 and nuts 293 Fit the gear control rods and selector gate rotor control and differential lock quadrant gear selector interlock mechanism and clutch rods as described in section D Fit and secure the engine throttle control and cable clips on Kohler models fit the air cleaner assembly 48 Section E 4h Locate the fuel tank and secure using the U bolts 360 spring washers and nuts Connect the fuel pipe and fill the tank with fuel NOTE On Hatz models fit the injector pump spill pipe and bleed the fuel system as described in the engine manufacturers handbook NEXT Fit the front shield as described in instruction 5 TO FIT THE FRONT SHIELD 324 5 Position the front shield over the rotor clutch and loosely secure in this position using the 3 setscrews E1 184 and setscrew E 1 187 but do not tighten at this stage as the shield may distort making it difficult to fit the remaining securing setscrews ba Slide the rotor assembly complete with the outer dust cover onto the rotor drive plate studs as shown in diagram E3 and support in this position on blocks etc NOTE The slot in the dust cover should be at the bottom 5b Locate
16. assemble the rotor clutch see instruction 8 THE CHAINCASE refer to illustration F6 on page 60 unless otherwise stated As no drain plug is fitted to the chaincase place a tray under the backplate to catch the oil when the cover is removed 3 Remove the chain tensioner adjusting screw 194 and remove the special frame bolt 182 3a Remove the wearing shoe 183 all the setscrews from around the perimeter of the chaincase and swing the weed cutter bracket aside The chaincase cover and gasket can now be removed from the backplate Chain tensioner 192 The chain tensioner arm is simply secured by a bolt and locknut The arm should be held as tight as possible by the nut and bolt yet sufficiently free to move under its own weight To fit the chaincase see instruction 10 TO REMOVE THE JACKSHAFT SPROCKET refer to illustration F6 on page 60 unless otherwise stated 4 Remove the chaincase as previously described in instruction 3 then proceed as follows 54 Section F 4a Remove the split pin 176 and special nut 175 which secure the sprocket to the jackshaft 155 NOTE To prevent the jackshaft from turning while removing the special nut position a thin bar or screwdriver blade through a top and bottom chain link as shown in illustration F3 to prevent movement Illustration F3 4b Remove the split p
17. be fitted to the speed change selector if so they should be retained as they may be required on assembly 8g Using a hammer and a soft brass drift through the rotor dog clutch selector housing tap the jackshaft from its location as shown in illustration C15 The jackshaft may then be removed from the gearbox together with the rotor clutch dog and shims D Illustration C15 29 Section C The bearing 11 may be partially removed from the jackshaft with the aid of special tool S 6 see section A as shown in illustration C16 The bearing may then be removed completely using a universal bearing puller Illustration C16 g press head crownwheel jackshaft rivet assembly bearing 11 special tool S6 Special note The crownwheel 13 is secured to the jackshaft 12 by Grivets 14 If the rivets are removed the new rivets should be inserted from the crownwheel side and burred over on the jackshaft flange These burrs should then be ground flat to prevent them from fouling the gearbox casing on reassembly The new bearing may then be pressed onto the jackshaft with the aid of a piece of 1 ID tube NEXT Fit assemble the jackshaft as described in instruction 9 TO FIT ASSEMBLE THE JACKSHAFT 9 Place 2 shims 10 onto the jackshaft against the bearing 11 Slide the rotor clutch dog onto the jackshaft and up to the shim 9a Using a soft headed hammer tap the j
18. bowl on the fuel tank Kohler models only 10 Check all nuts and bolts for tightness 11 Check tyre pressures are correct at 20 lbs sq in 1 4 kg sq cm 12 Adjust the weed cutter blades see rotor flange weedcutters overleaf EVERY 250hrs or 3MONTHLY Additional to 10 and 25 hrs maintenance 1 Drain the gearbox flush out and refill with 6 pints 3 4 litres S A E 90 gear oil see cleaning the gearbox overleaf 2 Remove the chaincase and wash the chain and the case with paraffin or kerosene Replace the case and refill with 2 pint 0 25 litres S A E 90 gear oil see cleaning chaincase overleaf 3 Check the wheel clutch settings see road wheels overleaf 4 Remove the air cleaner complete and flush out with paraffin or kerosene see air cleaner overleaf 63 Section G COMPONENT MAINTENANCE AIR CLEANER After 250 hours work the air cleaner should be completely removed and washed out using paraffin or kerosene including the upper half or pre cleaner When clean re assemble and fill with fresh oil up to the level mark CLEANING CHAINCASE After 250 hours of work the chaincase should be cleaned out Remove all the bolts securing the chaincase to the backplate allowing the chaincase oil to drain out from the joint as no drain plug is fitted Remove the cover ensuring that the gasket is not damaged and wash out the inside of the case and the drive chain using paraffin or
19. fixed dog 153 can be removed from the shaft by knocking out the pin using a hammer and a small punch When refitting the dog the end of the new pin should be burred over into the countersunk on each side of the fixed dog and the burrs should then be ground flat To remove the bearing 172 from the backplate insert a long piece of 1 dia bar through the jackshaft housing from the gearbox end and using a workshop press push the bearing from its location The new bearing may be pressed straight into its location using a workshop press The jackshaft housing 167 may be removed from the backplate by carefully drilling out the rivets 171 using a dia drill To ensure that the backplate to jackshaft housing location is correct when reriveting check that the threaded holes in the jackshaft housing end flange are in line with the corresponding threaded holes in the backplate around the housing location Jackshaft 155 to fit Position the jackshaft in the housing and using a suitable drift and a workshop press push the shaft through the bearing 172 until correctly located NEXT Fit assemble the backplate as described in instruction 6 TO FIT ASSEMBLE THE BACKPLATE refer to illustration F6 unless otherwise stated 6 Check that the rotor dog clutch sliding dog 152 and a new jackshaft housing gasket 151 are in position then proceed as follows 6a Locate the jackshaft housing over the sliding do
20. in design can be easily produced from the following dimensioned drawings SPECIAL TOOL S 1 is a clutch shaft puller used as specified in instruction 3a Section B to remove a broken clutch shaft SPECIAL TOOL S 2 is a hub puller used as specified in instruction 2 Section C to remove the wheel hubs SPECIAL TOOL S 3 is a pegged tool used as specified in Section C To dismantle the axle assembly to remove the loose hub gear bearing SPECIAL TOOL S 4 is an axle shaft puller used as specified in Section F Rotor stub axle to remove to remove the unbroken stub axle SPECIAL TOOL S 5 is a pegged tool used as specified in Section E Rotor drive shaft to remove to remove the rotor drive shaft sprocket bearing SPECIAL TOOL S 6 is a pegged tool used as specified in instruction 8g Section C to remove the bearing from the gearbox jackshaft SPECIAL TOOL S 7 is a pointer used in conjunction with 2 3 BSW nuts as specified in instruction 5b Section B to enable the crownwheel to pinion backlash to be assessed Section A Special Tools 3 ew dia bore e y Drill and tap tube to accept 2 z UNC x 1 long square headed setscrews Drill and tap bar to accept 2 3 UNF x 2 long setscrews SPECIAL TOOL S 1 3 pins 2 dia on a 2 25 PCD 4 holes 2 dia See ona 33 PCD 3 d
21. tape to protect the oilseal against the wheel axle splines slide the bearing stop up to the gearbox case as shown in illustration C23 Secure the bearing stop using the 4 setscrews 117 NOTE To prevent the possibility of an oil leak through the setscrews they should be coated with Hermatite before securing the bearing stop Wlustration C23 The engine has been removed for the purpose of this photograph only NEXT Fit the left hand wheel hub as described in instructions 15 and 16 34 Section C TO FIT THE GEARBOX COVER 14 Position the gearbox cover 24 against the gearbox casing so that the starting dog bearing 18 layshaft bearing 41 and wheel axle bearing 91 locate correctly Tap the cover into position and locate using the 2 dowel pins 28 Fully secure the cover using the setscrews 26 around the perimeter of the gearbox NOTE Fit the top inspection cover 5 with the trough towards the pinion to prevent foreign matter from entering the gearbox Fit the oil dipstick 14a Fit a new oilseal 90 into the gearbox cover using metal shim or tape to protect the oilseal against the splines on the loose hub gear as shown in illustration C24 and tap into position with the aid of a 17 ID piece of tube Illustration C24 oilseal 90 metal shim or tape h 14b Fit the starter dog bearing housing 21 comple
22. the bullwheel 98 from the differential pinion stud side such that the fixed hub gear locates in the centre of the bullwheel as shown in illustration C7 Locate one differential pinion 97 on each pinion stud on the bullwheel Position the loose hub gear 96 complete with bearing 91 over the end of the wheel axle checking that it is free to rotate against the fixed hub gear Position the remaining differential pinions on the bullwheel as shown 24 Section C in illustration C8 such that they mesh with the fixed hub gear the existing differential pinions and that they are positioned over their respective pinion pin location holes Invert the differential plate 94 and fit to the bullwheel such that the pinion pins 95 locate through the differential pinions and into the bullwheel Tap the plate to fully locate and secure using the special nuts 92 and split pins 93 Slide the differential lock assembly onto the wheel axle and check that it engages in the fixed and loose hub gears With the aid of a piece of 13 ID tubing tap the bearing 11 onto the end of the axle shaft To refit the axle assembly into the gearbox see instruction 12 Illustration C7 fixed hub gear rivet assembly Illustration CH differential pinions loose hub gear 96 25 Section C TO REMOVE DISMANTLE THE LAYSHAFT Illustration C9 6 6a 6b Remove the wheels and hubs gearbox co
23. the side frame 295 over the rotor stub axle and secure to the main frame using the 2 frame bolts 296 Fully tighten the frame bolts and secure using 16 swg locking wire 5c Fit and tighten the 5 setscrews 312 which secure the front shields to the side frame Fully tighten the 3 chaincase setscrews E1 184 and backplate setscrew E 1 187 5d Fit the rotor stub axle tab washer and nut Tighten the nut fully and secure by bending over the tab washer 5e Fit the springs and nuts to the rotor clutch drive plate studs and adjust the clutch as described at the end of Section F NEXT Fit the rear shield as described in instruction 6 TO FIT THE REAR SHIELD 325 6 Position the rear shield such that the depth control socket 278 locates through the slot in the top of the shield Hook the shield over the channel on the rear of the front shield and secure using setscrew 326 and washer 327 at each end of the shield pivot 6a Fit the shield clamping bolts 328 and secure using the flat washer 329 spring washer 330 and locknut 331 6b Position the depth control skid 279 or wheel arm 341 in the control socket 278 locating the peg of the depth control arm 280 through the skid and secure in position using the spring clip 281 49 Section E Illustration EA Main frame shields and handlebars Keep this page open when referring to section EI 50 DEPTH CONTROL WHEEL
24. using the pivot pin 430 and split pin 431 To remove the control arm 445 Remove the locknut 443 from the control rod eye bolt 442 and move the eye bolt and rod aside Slacken the setscrew 447 which secures the control arm to the ciutch operating pawl and remove the control arm and locating key 446 To fit the control arm 445 Position the control arm and locating key on the clutch operating pawl spindle and secure by tightening setscrew 447 Locate the control rod eye bolt 442 through the top of the control arm and secure using locknut 443 NOTE The philidas locknut 443 should be fully tightened and then slackened back approx half a turn such that the eye bolt is free to rotate under operational conditions To remove the hand lever 428 Remove the split pin 431 and pivot pin 430 from the adjusting link 432 and move the pivot lever rod aside 40 Section D With the aid of a punch remove the flat headed rivet 429 from the hand lever and then remove the lever A new rivet 429 will be required when refitting the hand lever To fit the hand lever 428 Position the hand lever on the handlebar locate using the flat headed rivet 429 inserted from the left hand side of the handle bar and burr the end of the rivet into the countersunk in the lever Position the adjusting link 432 between the lugs of the hand lever and secure using the pivot pin 430 and split pin 431 A
25. DJUSTMENTS SHOULD BE MADE AS DESCRIBED AT THE END OF THIS SECTION GEAR CHANGE CONTROL To remove the gear lever and gate Remove the 2 bolts which secure the gate 380 to the main frame and remove complete with the upper gear lever Do not lose the gear lever spring 378 Remove the nut 388 from the 3rd and reverse gear control rod eye bolt 387 Remove the pivot bolt 381 and remove the lower gear lever To fit the gear lever and gate Locate the control rod eye bolt 387 through the gear lever and secure using the nut 388 Secure the gear lever to the flange on the 1st 2nd gear control tube using the pivot bolt 381 and nut 383 Position the upper gear lever through the gate 380 and with the spring 378 located correctly in the upper lever position over the lower lever and secure the gate using the 2 bolts through the rear support bracket 384 and into the main frame To remove the gear control tube 389 and rod 390 Remove the gear lever rear bracket 384 and stay rod 373 then proceed as follows Slacken the retaining setscrews on the 3rd and reverse gear selector arm 396 and using a screwdriver blade lever the selector arm from its location NOTE Retain the locating key 394 and the brass universal joint 395 Slacken the retaining setscrew on the 1st 2nd gear selector arm 392 and using a screwdriver blade lever the selector arm from its location NOTE Retain the locating key 394 a
26. EM 24 models machine serial numbers 2592305 and 2306 GEM 30 models machine serial numbers 2591063 1067 1069 1070 1138 1139 1189 1190 1191 1394 and 1451 and all GEM V models from machine serial number 250A1021 The ratio of the gears was changed from 36 9 to 36 7 in order to reduce the forward travel speed of the machine and thus increase its performance The tater ratio gears can be supplied and fitted to machines prior to machine serial number 250A1021 but as a pair only as the new and the old bevel gears are not interchangeable and must be used with their respective pinions New parts Old parts Part number 27367 Bevel gear Part number 25008 Bevel gear Part number 27368 Clutch shaft Part number 25009 Clutch shaft Part number 25007 Pinion Part number 25061 Special nut Part number 208010160 Split pin The new 7 tooth pinion is an integral part of clutch shaft part number 27368 and this shaft can only be used with the single plate clutch assembly When fitting the new bevel gear part number 27367 to the gearbox jackshaft 6 4 dia x Z long rivets part number 208023040 will be required in place of the original amp dia xi long rivets which are too short o secure the new bevel gear Section B TO REMOVE THE KOHLER ENGINE 1 Refer to illustration B1 unless otherwise stated 582 583 584 SUPPLIED WITH KOHLER ENGINE 1a Disconnect the throttle control 569 from
27. GINE 10 1b Disconnect the small injector spill pipe from the engine Ic Disconnect the throttle cable clevis 626 from the engine and having removed the 2 bolts 630 from the throttle bracket 629 move the cable assembly aside 1d Release the engine starting handle from the spring clip 619 and withdraw the handle from the main frame tube le With the engine suitably supported on blocks etc remove the 8 setscrews 617 which secure the bell housing to the gearbox flange and retain the spring clip 619 The machine may then be moved clear of the engine TO FIT THE ENGINE See instruction 6 TO REMOVE THE BELL HOUSING 616 HATZ ENGINE Remove the 10 setscrews 620 and 2 bolts 622 which secure the bell housing to the engine and hence remove the housing TO REMOVE THE DRIVE ADAPTOR 611 HATZ ENGINE Remove the bell housing as previously described then remove the 6 setscrews 614 and spring washers 615 which secure the drive adaptor to the engine If the drive adaptor bearing 613 is to be renewed the old bearing may be pressed out from the back of the adaptor with the aid of a 1 dia drift The new bearing can then be pressed into its location greased and secured by positioning the special washer 612 over the bearing domed side outermost and with the aid of a small punch burr the lip of the bearing housing over the washer in 3 or 4 places TO FIT THE DRIVE ADAPTOR 611
28. HOWARD Howard Rotavator Co Ltd A member ofthe Howard group Saxham Bury St Edmunds Suffolk IP28 6RP England Telephone SE St Edmunds 0284 83265 Telex BIR RE KRA coe ay Dwectors J Austin Chawman P Coleclough J A Howard W M A Conran JH O Craig S B L Fraser F P O Moore G A Whymark A A Williama Pnnted in England Copynght Howard Rotavator Co Ltd October 1977 Regwtered Trade Marks Form No L 779
29. Sachs diesel From machine serial number 2541825 a Kohler K 301T engine has been fitted in place of the twin or from machine serial number 2571945 an alternative diesel engine the Hatz ES 780 has been used An improved version of the Hatz engine has been fitted from machine serial number 250A1021 and is designated the Hatz ES780U The super GEM is an up rated version of the Series V model produced specifically for contract work where greater strength and power are required Super GEM machines are fitted with either a Kohler K341 petrol or Hatz E785 diesel engine Section A Specifications SPECIFICATIONS STANDARD GEM Kohler K301T 4 stroke petrol producing 11h p max at 2800 r p m governed engine speed 22 lb ft 30Nm torque at 2200 r p m SUPER GEM Kohler K341T 4 stroke petrol producing 15h p max at 2800 r p m governed engine speed 28 Ib ft 38Nm torque at 2100 r p m STANDARD GEM Hatz ES780U stroke diesel producing 9h p max at 3000 r p m governed engine speed 19 Ib ft 25 75 Nm torque at 2100 r p m SUPER GEM Hatz E785 4 stroke diesel producing 11h p max at 3000 r p m governed engine speed 23 Ib ft 31Nm torque at 2100 r p m These engines are air cooled and fitted with an automatic compression release for easy starting TRANSMISSION 3 forward gears and one reverse Full differential with an automatic locking device on engaging the rotor Rotor safety clutch with a slip action when under shock load
30. ackets and four others which also secure the chaincase wearing shoe 183 NOTE The setscrews 184 vary in length around the perimeter of the chaincase and should be used as shown in the small inset to illustration F6 on page 60 Setscrew A is 4 BSW x long setscrew B is A BSW x 3 long setscrew C is 4 BSW x 2 long and setscrew D is 4 BSW x 4 long 10a Fit and tighten the frame bolt 182 then fit the chain tensioner adjusting screw The drive chain tension may be adjusted as described at the end of this section 10b Fill the chaincase with s pint 0 25 litres of SAE 90 gear oil 59 Section F ADJUSTMENTS Illustration E Illustration EZ Drive chain The drive chain tension should be checked and adjusted so that the total up 3r and down movement is between 2 9 5 mm and 12 7 mm The tension of the chain can be checked by inserting a screwdriver through the oil filler hole in the chaincase and into one of the chain links Turn the screwdriver so that the chain is gripped and having loosened the locknut on the chain tensioner adjusting screw adjust to give the correct movement Screwing in of the adjusting screw will tighten the chain and vice versa Tighten the adjusting screw locknut and recheck tension if correct replace the chaincase oil filler plug Rotor clutch For normal setting tighten the nuts to fully compress the springs the
31. ackshaft and bearing into its location in the gearbox casing as shown in illustration C17 NOTE It is advisable to fit the clutch shaft at this stage so that the correct crownwheel to pinion backlash may be achieved To fit the clutch shaft and adjust the backlash refer to instructions 10 to 10c inclusive When the backlash is correct proceed as follows 9b Fit and secure the rotor dog clutch selector housing using the bolts 160 shown in illustration C13 Qc Slide the double pinion 16 onto the jackshaft small gear first Fit the speed change selector 29 such that the selector block locates in the double pinion and in the gearbox case Secure in position using the selector bush 3 30 Section C Illustration C17 crownwheel jackshaft rivet assembly NOTE The speed change selector should have approx free movement up and down This may be achieved by adding washers 31 between the selector bush and the selector to decrease the movement or by adding shims 3B between the selector bush and the gearbox case to increase the free movement 9d Slide the single pinion 17 onto the jackshaft gear side outermost Fit the reverse selector 30 such that it locates in the groove in the single pinion NOTE The reverse selector should have approx vU free movement up and down This may be achieved by adding washers 31 between the selector bush and the selector to decrease the movement or by
32. adding shims 38 between the selector bush and the gearbox case to increase the free movement Je Fit the special circlip 15 to the end of the jackshaft and position the starting dog bearing 18 over the end of the jackshaft 9f Fit the gear change selector arms and check that the interlock plates on the arms function correctly NEXT Fit the remaining clutch assembly parts as described in instruction 10c onwards TO FIT THE CLUTCH SHAFT 10 Position the clutch shaft through the oilseal hole in the clutch housing and using a soft headed hammer tap the shaft into its location as shown in illustration C18 When tapping the clutch shaft into its location frequently turn the clutch shaft by hand to ensure that it does not become jammed in the crownwheel 10a Secure the shaft bearing in position using the circlip 63 and position the ears of the circlip at the top 10b To obtain the correct backlash 0 010 between the crownwheel and pinion proceed as follows Position a 3 long piece of 2 OD tubing over the clutch shaft and by means of the clutch securing nut some washers and the thread on the clutch shaft draw the pinion out of mesh with the crownwheel as shown in illustration C19 until the circlip prevents further movement 31 Section C Illustration C18 Illustration C19 Illustration C20 While holding the clutch shaft to prevent its rotation gently t
33. al or a reverse gear Series machines were produced from serial number 101 up to machine serial number 4800 and these machines were fitted with the HOWARD BJJ engine Swinging type handlebars and a differential were introduced at the start of the series II GEM and later they were equiped with a reverse gear operated by a lift up lever Series II machines were produced from serial number 4801 up to machine serial number 14784 and these machines were fitted with the original HOWARD B J or a J A P 600cc engine SERIES III AND IV SERIES V SUPER GEM Production of series III and IV machines overlapped The basic machine remained the same for both only the engines were different Series Ill machines were produced from serial number 14785 and were fitted with either the HOWARD B J or a J A P 600cc engine During production of the series III the first series IV machines were phased in These machines were fitted with anew HOWARD engine the 180 Twin From machine serial number 38760 series IV machines only were produced but were fitted with an improved version of the twin engine the HOWARD 360 Twin or alternatively a water cooled Sachs diesel engine Series IV machines were discontinued at machine serial number 47066 This is the current series of GEM which was introduced at machine serial number 47067 Machines up to serial number 2541824 were fitted with an up rated version of the HOWARD 360 Twin engine or the
34. ars Possible Cause incorrect adjustment worn clutch plates incorrect adjustment clutch control arm loose and or worn locating key engine drive adaptor bearing seized clutch thrust sleeve seized to shaft incorrect engine clutch adjustment gear selector arm interlocks bent gear selector arms loose and or worn locating key gear selectors too tight or too loose in the gearbox gear selector inner control rod seized in outer tube splines on jackshaft twisted inside the gearbox worn gear selectors inside gearbox differential lock control quadrant obstructed loose hub gear cannot freely rotate gear selector arm to control rod joint blocks tight or worn internal gears worn 66 Remedy adjust to correct setting adjust to compensate for wear If all adjustment taken up and clutch still slips replace worn parts adjust to correct setting tighten arm securing bolt and or replace locating key replace with a new bearing and lubricate free sleeve and lubricate or replace sleeve if damaged adjust to correct setting straighten interlocks and adjust selector arms tighten selector arm securing bolt and or replace locating key adjust to give correct amount of free play free and lubricate then adjust replace gearbox jackshaft replace internal selectors check for obstructions and remove if any check loose hub gear bearing for wear and replace if necessary if tigh
35. d refilled with fresh oil Check to ensure that the sealing surfaces are not damaged in any way The air cleaner is one of the most important parts of the engine and if correct servicing is carried out will help prolong the life of the engine CONTENTS Subject AXLE BEARING STOP CLUTCH SHAFT ASSEMBLY CLUTCH SHAFT PINION BEARING DIFFERENTIAL ASSEMBLY DIFFERENTIAL LOCK GEARBOX COVER JACKSHAFT ASSEMBLY LAYSHAFT ASSEMBLY REVERSE IDLER GEAR ROAD WHEELS TYRES WHEEL AXLE ASSEMBLY Action Fitting Removal Fitting Removal Fitting Removal Assemble Dismantle Assemble Dismantle Fitting Removal Assemble Dismantle Fitting Removal Assemble Dismantle Fitting Removal Fitting Removal Description Fitting Removal Assembly Dismantle Fitting Removal WHEEL FRICTION CLUTCHES Fitting Removal SERVICE BULLETINS APPERTAINING TO THIS SECTION ARE TOOLS LIST Bulletin No No off mh mh sch ee m mm mm m m d SPECIAL EQUIPMENT Container tray of at least 6 pints capacity Universal bearing puller 2 legged Self grip wrench A7 BSW Box spanner 2 BSW Ring spanner 2 BSW Open ended spanner Z BSW Ring spanner 2 BSW Ring spanner 2 BSW Ring spanner GT BSW Open ended spanner 2 BSW Ring spanner Pair 6 engineers pliers Pair right angled internal circlip pliers Dial test indicator and magnetic stand No off at ad m Copper Rawhide malle
36. d tighten such that the spring holds the hand lever securely in the notches in the gear quadrant ADJUSTMENTS SHOULD BE MADE AS DESCRIBED AT THE END OF THIS SECTION 39 Section D CLUTCH CONTROL To remove the pivot lever to control arm rod 440 Remove the nut 443 from the eye bolt 442 on the clutch control arm 445 and then remove the eye bolt Remove the split pin 439 from the control arm rod 440 at the pivot lever end To fit the pivot lever to control arm rod 440 Locate the end of the rod through the pivot lever 436 and pivot lever rod 434 and secure using the flat washer and split pin Position the eye bolt 442 through the control arm 445 and secure using nut 443 NOTE The philidas locknut should be fully tightened and then slackened back approx half a turn such that the eye bolt is free to rotate under operationa conditions To remove the hand lever to pivot lever rod 434 Remove the split pin 439 from the control arm rod 440 at the pivot lever 436 and move the control arm rod aside Remove the split pin 431 from the hand lever pivot pin 430 and remove the pivot pin and rod To fit the hand lever to pivot lever rod 434 Locate the control arm rod 440 through the pivot lever 436 and position the pivot lever rod over the control arm rod and secure using the flat washer and split pin Position the adjusting link 432 between the lugs of the hand lever and secure
37. ear bearing 91 is to be replaced a special tool S3 similar in appearance to the differential lock assembly will be required in order to be able to press the bearing from its location Using the special tool S3 see special tools section A working from the back face of the loose hub gear through the holes provided in the gear flange press the bearing from its location as shown in illustration CD The loose hub gear can then be pressed through the new bearing using an ordinary workshop press Withdraw the wheel axle and fixed hub rivet assembly from the bullwheel 98 The fixed hub gear 100 is secured to the wheel axle flange by 6 rivets 102 If for any reason these rivets are removed the new rivets should be inserted from the axle flange side of the fixed hub gear and burred over on the fixed hub gear side The burrs must then be ground flat to prevent them fouling the loose hub gear when the differential unit is reassembled If the pinion pins 95 located in the differential plate 94 are to be replaced the new pins should be burred over to secure The pinion studs 99 in the bullwheel if replaced must have the burred ends ground flat to prevent them fouling on the small gear 44 on the layshaft 50 when the gearbox is reassembled press head loose hub gear 96 bearing 91 __ special tool S3 TO ASSEMBLE THE DIFFERENTIAL UNIT Position the wheel axle and fixed hub gear rivet assembly through
38. eel axle by a special hub nut 87 Removal of this hub nut will allow the wheel hub to be withdrawn from the axle with the aid of a hub puller as shown in illustration C1 see special tool S2 section A The left hand wheel hub 118 is secured to the wheel axle by a split pin 121 and a special nut 120 Removal of these and the backing washer 119 will allow the wheel hub to be withdrawn from the axle with the aid of a hub puller in a similar manner to that shown in illustration C1 see special tool S2 section A To refit the wheel hubs see instruction 15 20 Section C TO REMOVE THE AXLE BEARING STOP 115 Drain the oil from the gearbox a container of at least 6 pints capacity will be required Remove the left hand wheel and hub as previously described in instructions 1 and 2 then proceed as follows 3 Remove the 4 setscrews 117 and spring washers 116 which secure the bearing stop to the main gearbox casing NOTE The oilseal 113 should always be renewed before refitting the bearing stop To refit the axle bearing stop see instruction 13 TO REMOVE THE GEARBOX COVER 24 4 Drain the oil from the gearbox a container of at least 6 pints capacity will be required Remove the right hand wheel and hub as previously described in instructions 1 and 2 Remove the starting handle then proceed as follows 4a Remove the setscrews 22 and spring washers 23 from the sta
39. en and the gearbox has to be dismantled check that the engine and engine clutch see section B gearbox cover wheel axle and layshaft assemblies have all been removed then proceed as follows 7a Remove the special oilseal 68 and thrust sleeve 66 from the clutch housing and slide the thrust bearing 65 from the shaft 7b Remove the circlip 63 from the pinion bearing housing and using a self grip wrench remove the shaft as shown in illustration C10 Illustration C10 i i i D dei a To remove the pinion bearing To remove the bearing from a clutch shaft where the pinion is a separate component to the clutch shaft proceed as follows Remove the split pin and special nut from the front of the pinion and using a workshop press push the shaft from the pinion and bearing as shown in illustration C11 To reassemble The shaft can be pressed into the bearing and the pinion replaced and secured by the special nut and split pin To remove the bearing from a clutch shaft where the drive pinion is an integral part of the shaft proceed as follows Working from the back of the pinion carefully support the outer cup of the bearing and using a workshop press push the shaft from the bearing as shown in illustration C12 To reassemble The shaft can be pressed through the new bearing until it is against the shoulder at the back of the pinion To refit the clutch shaft see instruction 10
40. ess otherwise stated all the illustration numbers in this section refer to diagram D1 which can be found at the end of this section on page 44 DIFFERENTIAL CONTROL To remove the differential control rod 417 Remove the nut 421 and washer 422 from the eye bolt 420 on the end of the control rod and withdraw the eye bolt from its location Remove the split pin 418 from the rotor control rod block and hence remove the rod complete with the eye bolt and springs To remove the differential control arm 423 Remove the differential control rod then proceed as follows remove the split pin 425 from the quadrant pin 424 which acts as the pivot pin for the control arm and hence remove the pin and the control quadrant To fit the differential control arm 423 Position the differential lock selector quadrant over the differential lock trunnion 426 Slide the quadrant pin 424 through the main frame and into the quadrant such that the split pin 425 may be inserted through the quadrant pin between the main frame and the top of the quadrant To fit the differential control rod 417 Position the rod through the locating block on the rotor control rod and secure in position using split pin 418 Position the eye bolt 420 in the differential lock selector quadrant and secure using the flat washer and nut 421 NOTE The securing nut should be fully tightened and then slackened back approx half a turn such t
41. etscrews 617 DISENGAGE REVERSE GEAR BEFORE CONTINUING 6b Reconnect the injector spill pipe to the engine using the small banjo bolt with a gasket washer between the pipe and the engine and between the bolt head and the pipe 6c Reconnect the fuel line to the fuel pump on the side of the engine using a gasket washer each side of the pipe and bleed the fuel system as described in the engine manufacturers handbook 6d Position the throttle bracket 629 against the side of the engine and secure using the 2 bolts 630 6e Reconnect the throttle cable clevis 626 to the speed control lever on the engine NOTE Before starting the engine check that the oil level in the engine sump is correct see engine handbook ADJUSTMENTS Engine Adjustments to the engine should be made as described in the engine manufacturers handbook Engine clutch Adjustment of the engine clutch is achieved by turning the wing nut on the end of the clutch control rod To tighten the clutch i e to stop it from slipping and adjust for normal wear the wing nut should be unscrewed To slacken the engine clutch i e when it does not disengage properly the wing nut should be screwed up When correctly adjusted there should be 4 of free movement at the operating lever engine end of clutch rod Engine air cleaner Both the Hatz and the Kohler engines use an oil bath type of air cleaner assembly which should be cleaned daily an
42. from turning using a large flat bladed screwdriver To check the crownwheel to pinion backlash NOTE Because the crownwheel to pinion backlash can only be accurately checked using a dial test indicator when the gearbox is dismantled the following method of assessing the backlash should only be used as a guide Locate the pointed special tool S 7 see section A over the clutch shaft and clutch unit securing bolts and secure in position using j BSW nuts Use a suitable bar through the gearbox top inspection hole to jam the crownwheel and prevent its rotation Rotate the clutch unit backwards and forwards and mark the furthest points of movement of the special tool as shown in illustration B10 The distance between these marks should be approx 3 mm when the backlash is correct If incorrect the backplate and chaincase assembly must be removed so that shim may be added between the jackshaft housing and the jackshaft bearing to decrease the backlash or gaskets added between the jackshaft housing and the gearbox case to increase the backlash The backplate and chaincase assembly should then be replaced and secured and the backlash rechecked 16 Section B TO FIT THE ENGINE 6 When refitting the engine engage reverse gear or secure the handle bar clutch lever in the up position as this will hold the engine clutch unit in the disengaged position and will allow free movement of the clutch disc s whe
43. g and fit the frame bolt 190 which will support the weight of the backplate 6b Fit the jackshaft housing securing bolts 163 and 164 and fully tighten these bolts and the frame bolt 190 Secure using locking wire 6c Reposition the rotor dog clutch selector housing 159 ensuring that the selector block 156 locates correctly in the groove in the sliding dog and secure using the 3 setscrews 160 6d Refit the front and rear shield assembly and secure the front shield to the top of the backplate using the setscrew 187 spring washer and nut NEXT Fit the jackshaft sprocket as described in instruction 7 57 Section F TO FIT THE JACKSHAFT SPROCKET refer to illustration F6 on page 60 unless otherwise stated 7 Illustration F5 7a Locate the jackshaft sprocket 172 on the jackshaft Using a straight edge positioned across the face of the jackshaft and rotor drive shaft sprockets as shown in illustration F5 check that the sprockets are in line Shim 173 should be added behind the jackshaft sprocket as necessary to produce the correct alignment Fit the special nut 175 to the jackshaft Fit the drive chain and secure the connecting link using the split pin s 7b Position a thin bar or screwdriver blade through the drive chain as shown in illustration F3 to prevent the sprocket from turning while tightening the special nut 175 Secure using a
44. ge 60 unless otherwise stated 1 Support the rear of the machine clear of the ground so that the rear shield may be fully raised and the depth skid removed Then proceed as follows la Remove the nuts 215 and springs 214 from the rotor drive plate studs 1b Undo the locking tab 230 and remove the nut 231 from the rotor stub axle 1c Remove the locking wire from the 2 frame bolts shown in illustration F1 and remove the 5 setscrews F 1 312 spring washers and nuts which secure the sideframe to the front shield Remove the bolt F 1 326 which secures the sideframe to the rear shield Illustration EI 1d While supporting the rotor assembly on blocks etc remove the 2 frame bolts and the sideframe le Turn the rotor assembly such that the right hand end blades are parallel with the bottom edge of the front shield and slide the rotor as far to the right as possible so that it may be removed from the clutch drive plate studs complete with the dust cover 237 52 Section F Rotor stub axle to remove Remove the outer dust cover 237 and unscrew the round bearing cap 228 which has a left hand thread With the aid of a special puller S 4 see special tools Section A and the rotor stub axle nut remove the stub axle as shown in illustration F2 Hlustration EA stub axle nut If the special puller cannot be used due to breakage of the roto
45. hat the eye bolt is able to rotate under operational conditions ADJUSTMENTS SHOULD BE MADE AS DESCRIBED AT THE END OF THIS SECTION ROTOR CONTROL To remove the rotor control rod 410 Remove the split pin 418 from the differential lock selector control rod Withdraw the rod from the block and move aside Remove the nut 413 from the eye bolt 412 and hence remove the eye bolt from the rotor control arm 414 Remove the split pin 409 from the hand lever end of the rotor control rod 410 and then remove the rod To fit the rotor control rod 410 Position the eye bolt 412 through the rotor control arm 414 and secure using nut 413 NOTE The securing nut should be fully tightened and then slackened back approx half a turn such that the eye bolt is free to rotate under operational conditions Locate the top of the rotor contro rod in the hand control lever 406 and secure using split pin 418 38 Section D CONTROL HAND LEVER To remove the hand control lever 406 Remove the split pin 409 from the rotor control rod 410 and move the rod clear Remove the philidas locknut 408 and spring 407 and then remove the hand lever from the gear control quadrant 405 To fit the hand contro lever 406 Position the control lever over the threaded shaft on the gear control quadrant 405 Fit the spring 407 and nut 408 and tighten such that the spring holds the hand lever securely
46. heel axle oilseal located in the gearbox cover should be removed before refitting the cover to the main gearbox case so that a new oilseal may be used on assembly The old seal may be pressed out with the aid of a 23 dia drift To refit the gearbox cover see instruction 14 21 Section C TO REMOVE THE WHEEL AXLE ASSEMBLY 5 Having removed the wheels and hubs axle bearing stop and gearbox cover as previously described in instructions 1 4 proceed as follows 5a Remove the retaining split pin from the differential lock control quadrant pivot pin and slide the pivot pin out of the control quadrant as far as possible and remove the locknuts and trunnion shown in illustration C2 from the differential lock selector Sb Remove the split pin 40 and special nut 39 from the end of the layshaft 50 and remove the bearing 41 Hlustration C 2 locknuts trunnion e 5c While supporting the axle by hand tap the axle assembly from its location in the main gearbox casing using a soft headed hammer as shown in illustration C3 Illustration C 3 The engine has been removed for the purpose of this photograph only NOTE On removal of the axle assembly the differential lock selector will also be removed from its location TO DISMANTLE THE AXLE ASSEMBLY Remove the axle bearing 110 from the end of the axle shaft using a universal bearing puller as shown in illustration C4
47. hide mallet Pair 6 engineers pliers Pair right angled internal circlip pliers Pair straight internal circlip pliers ott m mak Container tray of at least 6 pints capacity SPECIAL TOOLS Special tool S 1 Special tool S 7 and 2 3 BSW Nuts 7 Section B HISTORY ENGINES The Kohler K 301T has been fitted from machine serial number 2541825 and is a 477cc 4 stroke petrol engine of 10hp From machine serial number 2571945 the Hatz ES 80 diesel engine has been available as an alternative to the Kohler engine The Hatz is a 500cc 4 stroke diesel engine of 10 hp An improved version of the Hatz engine having an antivibration front cover and designated ES 780U has been fitted from machine serial number 250A1021 ENGINE CLUTCH All Kohler and Hatz engined machines are now fitted with a single plate clutch Machines prior to serial number 2571414 were fitted with a double plate clutch and the following parts are required if converting the clutch assembly to the single plate version Part number Part description No Off 288 Thrust sleeve 1 255 Distance piece 4 250 Special bolt 4 The clutch assembly should be rebuilt substituting these parts for the existing components and one fibre disc and one loose plate should be discarded from the original assembly A new clutch shaft part number 25009 will also be required CLUTCH SHAFT CROWNWHEEL AND PINION NOTE The crown wheel and pinion were changed on G
48. ia SPECIAL TOOL S 3 UNC x 2 long setscrew 2 UNC x 3 long setscrew y x UNC nut welded to plate SPECIAL TOOL S 2 Drill 3 dia fill with weld then file to shape of stub axle SPECIAL TOOL S 4 1 Bes 2 pins dia 2 pins e dia 3 dia d 1 dia hole SPECIAL TOOL S 5 SES 2 Holes 33 Dia SPECIAL TOOL S 7 CONTENTS Section B zzz el Subject Action Page ADJUSTMENTS 18 BELL HOUSING Fitting Hatz 11 Kohler 10 Removal Hatz 11 Kohler 10 CLUTCH SHAFT AND PINION HISTORY 8 CLUTCH SHAFT Fitting 16 Removal 13 CLUTCH SHAFT BEARING Fitting 15 Removal 15 DRIVE ADAPTOR Fitting Hatz 11 Kohler 10 Removal Hatz 11 Kohler 9 ENGINE HATZ Description 8 Fitting 17 Removal 10 KOHLER Description 8 Fitting 17 Removal 9 ENGINE CLUTCH Assemble 13 Dismantle 12 Fitting 16 Removal 11 SERVICE BULLETINS APPERTAINING TO THIS SECTION ARE TOOLS LIST Bulletin No No off 1 Small electrical screwdriver 1 Large screwdriver 1 14 BSW Open ended spanner 1 BSW Box spanner 1 3 BSW Open ended spanner 1 2 BSW Ring spanner 1 2 BSW Ring spanner 1 2 AF Ring spanner 1 3 AF Box spanner 1 1 1 1 1 we AF Open ended spanner AF Ring spanner Sq Extended box spanner 12mm Open ended spanner 13mm Open ended spanner DM HAD SPECIAL EQUIPMENT Hermatite Steel rule No off Small punch Copper Raw
49. il the bearing releases from its housing NOTE It may be necessary to prevent the clutch shaft from turning by inserting a suitable bar through the gearbox top inspection hole and into the crownwheel and pinion teeth 13 Section B Illustration B 6 e w The gearbox cover and internal components have been removed for the purpose of this photograph only Illustration B 7a Hlustration B 7b e Special Tool SI 14 Section B Alternatively where the shaft is broken at a point behind the thread position the tube part of special puller S 1 see Section A special tools over the clutch shaft as shown in illustration B7b and secure by tightening the two square headed setscrews Then the shaft may be withdrawn by screwing in the two setscrews on the flat front face of the puller NOTE The special clutch shaft puller should not be used in cases where the same clutch shaft is to be replaced as the square headed set screws may score the shaft which would cause the clutch thrust sleeve to seize during operation 3e Withdraw the shaft complete with the thrust race circlip and bearing through the oilseal aperture in the clutch housing The circlip will need to be compressed with a pair of circlip pliers before it will pass through into the clutch housing TO REMOVE FIT THE CLUTCH SHAFT BEARING To remove the bearing from a clutch shaft where the drive pinion is a separate component to the
50. in s from the drive chain connecting link and using a screw driver prise the link apart Remove the link and chain Removal of the connecting link is best done near the jackshaft sprocket so that the chain will bend sideways allowing the link to be removed The jackshaft sprocket and any shim which may be fitted can now be removed To fit the jackshaft sprocket see instruction 7 TO REMOVE DISMANTLE THE BACKPLATE ASSEMBLY refer to illustration F6 unless otherwise stated 5 Remove the rotor assembly rotor clutch chaincase and jackshaft sprocket as described in instructions 1 4 then proceed as follows 5a Remove the shield retaining setscrew from the top of the backplate and hence remove the front and rear main shield assembly 5b Remove the rotor dog clutch selector housing 159 by removing the 3 setscrews 160 and move the housing aside 5c Remove the locking wire from the setscrews 163 and 164 and remove these setscrews which secure the jackshaft housing to the gearbox case 5d Remove the locking wire from the frame bolt 190 while supporting the backplate by hand unscrew the frame bolt and remove the backplate 55 Section E Illustration F4 Rotor drive shaft sprocket 202 to remove With the aid of a workshop press push the shaft from its location and retain the spacer 205 To remove the bearing 203 from the rotor drive shaft sprocket a special tool S 5 wil
51. in the notches in the gear quadrant Fit the rotor control rod 410 to the hand lever and secure using split pin 409 ADJUSTMENTS SHOULD BE MADE AS DESCRIBED AT THE END OF THIS SECTION GEAR CONTROL QUADRANT To remove the gear control quadrant 405 Remove the philidas locknut 408 and spring 407 from the hand control lever and move the lever aside Remove nut 399 and setscrew 398 and remove the handlebar positioning arm 397 Remove the split pin 404 from the positioning pin 401 Remove the positioning pin and spring 402 Remove the 2 setscrews which secure the control quadrant to the main frame NOTE These setscrews also secure the depth control skid socket To fit the gear control quadrant 405 Position the control quadrant on the main frame with the lug facing forward and secure using the 2 setscrews which also retain the depth skid socket Position spring 402 inside the quadrant and slide the positioning pin 401 through the quadrant and spring and secure using split pin 404 Locate the positioning arm 397 over the positioning pin 401 and secure the arm to the quadrant using setscrew 398 washer 400 and philidas locknut 399 NOTE The philidas locknut should be fully tightened and then slackened back approx half a turn such that the positioning arm is free to move Locate the control hand lever 406 over the shaft on the gear control quadrant fit spring 407 and nut 408 an
52. kerosene Re assemble and fill with g pint 25 litres S A E 90 gear oil CLEANING GEARBOX The gearbox must be cleaned out after 250 hours work Unscrew the drain plug on the bottom right hand inner side of the gearbox and drain immediately after a period of running The oil will be warm and free running and any sediment will be held in suspension in the oil Replace the drain plug and refill the gearbox with about 6 pints 3 4 litres of flushing oil Run the machine for about 3 mins with the rotor well clear of the ground then drain the flushing oil Refill the gearbox with 6 pints 3 4 litres of good quality S A E 90 gear oil ROAD WHEELS Each road wheel is mounted on its hub by a friction clutch device These are adjusted so that the wheels have sufficient grip to pull the machine but will slip if they become jammed with an obstruction between the wheels and frame For normal adjustment tighten each of the four nuts to fully compress the springs then slacken back each nut half a turn Should the wheels appear not to be driving check that the adjustment is correct and adjust as necessary ROTOR FRICTION DRIVE The rotor to which the blades are bolted is driven direct from the main gearbox through a friction clutch This clutch should only operate when the rotor blade strikes an obstacle if the clutch appears to slip too easily it can be adjusted by tightening the four clutch nuts to fully compress the springs then s
53. l be required as described in Section AT Position the studs of the tool through the holes in the back of the drive shaft sprocket and using a workshop press as shown in illustration F4 remove the bearing The new bearing may be pressed onto the drive shaft sprocket with the aid of a 1 ID piece of tube Press head drive shaft sprocket bearing 203 special tool S5 Rotor drive shaft sprocket oilseal 204 may be pressed from its location with the aid of a 2 dia drift and a workshop press The new oilseal may be pressed into position flat side of seal towards the rotor until flush with the housing Rotor bearing housing 170 may be removed by carefully drilling out the rivets 171 using a dia drill 56 Section E When reriveting the housing to the backplate check that the slot in the dust cover 169 is positioned at the bottom when the backplate is in the working position The new rivets should be inserted from the backplate side and burred over on the bearing housing Excessive burrs should be removed using a small hand grinder to prevent them from fouling the drive plate 209 when the rotor clutch is assembled Rotor drive shaft sprocket 202 to fit Position the rotor drive shaft sprocket and bearing against the rotor bearing housing and press into the housing Jackshaft 155 to remove The jackshaft may be pushed from the bearing 172 using a workshop press The
54. lacken back each nut half a turn ROTOR FLANGE WEEDCUTTERS Two weedcutter blades are provided one at each side of the machine tu prevent long grass or weeds binding around the rotor end flanges These blades are slotted and secured by two setscrews each and they should be adjusted so that they just clear the rotor flanges when the rotor is turned BY HAND Severe power losses will occur in weedy conditions unless these blades are correctly adjusted 64 Section G MAINTENANCE OF BLADES Only the cutting edge of the blade should rub in the soil the backs of the blades should be clear The efficiency of the machine is determined largely by the condition of the blades If they are bent or distorted through striking solid obstacles in the ground and are not replaced they will require greater power to drive them and the quality of work will be poor Trouble will also arise with clogging under the shield BLADE IN CORRECT ALIGNMENT aT ip p TWISTED IB BLADE l f gt RJ 32 CLEARANCE LA STRAIGHT EDGE CUTTING EDGE V BACK EDGE DIRECTION OF TRAVEL R H BLADE 3 WE CLEARANCE WEN How to identify right and left hand blades NORSE NO EZR GK R E H rete rcs Correct blade setting showing clearance at back of blade 65 Section G MACHINE FAULT FINDING Fault Engine clutch slips Engine clutch does not disengage properly Difficulty in engaging ge
55. location frequently turn the clutch shaft by hand to ensure that the pinion does not become jammed in the crownwheel 4c Using a pair of right angled circlip pliers through the gearbox top inspection hole secure the clutch shaft bearing in its housing using the circlip already suspended on the shaft 4d Use the ube method described in instruction 3d to pull the bearing back against the circlip The crownwheel to pinion backlash can not be checked until the clutch unit has been fitted 4e Slide the thrust bearing onto the clutch shaft and up to the operating pawl 4f Smear a small amount of Hermatite around the locating flange of the special oilseal Fit the oilseal together with the thrust sieeve and secure in position using the 3 setscrews 4g Refill the gearbox with 6 pints 3 4 litres of good quality SAE 90 gear oil and refit the top inspection cover with the trough towards the pinion TO FIT CLUTCH UNIT 5 Position the clutch unit on the clutch shaft and slide up to the thrust sleeve ensuring that the peg on the clutch thrust plate is positioned to the side of the raised section of the thrust sleeve This ensures that the thrust sleeve rotates in the special oilseal during operation 5a Slide the spacer onto the clutch shaft double plate clutches only and secure the assembly using the special nut and split pin When tightening the clutch retaining nut the clutch unit should be restrained
56. lutcl Illustration C25 Gearbox assembly wheels and hubs Keep this page open when referring to section C 36 ympressed then slacken safety clutch device will he machine is in normal gt is acquired to produce A kg sq cm and that zontrol should be made This illustration shows the twin plate clutch assembly and clutch shaft with loose pinion p SE uth E CONTENTS SERVICE BULLETINS APPERTAINING TO THIS SECTION ARE TOOLS LIST Subject Action CLUTCH Adjustment CLUTCH CONTROL ARM Fitting Removal CLUTCH CONTROL ARM RODFitting Removal CLUTCH CONTROL HAND LEVER Fitting Removal CLUTCH CONTROL PIVOT LEVER ROD Fitting Removal DIFFERENTIAL CONTROL ARM Fitting Removal DIFFERENTIAL CONTROL ROD Fitting Removal DIFFERENTIAL LOCK Adjustment DIFFERENTIAL ROTOR HAND CONTROL LEVER Fitting Removal GEAR CHANGE CONTROL TUBE Fitting Removal GEAR CHANGE GATE Fitting Removal GEAR CHANGE LEVER Fitting Removal GEAR CHANGE ROD Fitting Removal GEAR CONTROL QUADRANT Fitting Removal PIVOT LEVER ROD Fitting Removal REVERSE INTERLOCK Adjustment Fitting Removal ROTOR DOG CLUTCH Adjustment ROTOR CONTROL ROD Fitting Removal Bulletin No No off 2 LIT BSW Open ended spanners 1 4 BSW Open ended spanner 2 3 BSW Open ended spanners 1 Pair 6 engineers pliers 1 Small punch 1 Copper Rawhide mallet 1 1 Ib Ball pein hammer 37 Section D Section D Unl
57. n Secure the vertical link 453 to the rocker using the setscrew 451 and nut Locate the rod 454 through the main frame and twist such that it locates in the vertical link Position a flat washer 455 spring 456 and flat washer 455 over the rod and secure using the locknut 457 ADJUSTMENTS SHOULD BE MADE AS DESCRIBED AT THE END OF THIS SECTION 42 Section D ADJUSTMENTS Clutch adjustment rr The clutch should be adjusted to give a 5 6 mm free movement at the clutch operating arm 445 Adjustments should be taken up at the control arm by means of the wing nut 444 NOTE If the clutch slips during operation the control rod wing nut should be UNSCREWED If the clutch does not disengage properly the wing nut should be screwed further onto the rod Final adjustment should be checked with the machine under operational conditions and further adjustment made as necessary Gear selector control adjustment The speed change and reverse selectors located in the gearbox should have approx sz free movement up and down This may be achieved by adding washers C1 31 between the selector bush and the selector to decrease movement or by adding shim C1 38 between the selector bush and the top of the gearbox case to increase free movement Check that the brass universal joint blocks slide freely on the selector arms and the control rod tube If tight ream as necessary to provide a close sliding fit
58. n aligning the drive adaptor pins with the holes in the friction disc s To fit the Kohler engine refer to illustration B1 unless otherwise stated 6a Support the engine in position such that the drive adaptor pins locate in the engine clutch and with the bell housing location holes in line with those in the gearbox flange secure the bell housing to the gearbox using the 8 setscrews 558 Tighten these setscrews to a torque of 10 Ibs ft 1 3 kg m DISENGAGE REVERSE GEAR BEFORE CONTINUING 6b Fit the stop switch cable 573 to the engine mounted condenser 6c Fit the air cleaner hose 595 to the induction elbow and secure using the jubilee clip 594 6d Reconnect the throttle control 569 to the engine using the small clamp bolt Ge Reconnect the fuel pipe 585 to the engine and the fuel filter bowl and turn on the petrol NOTE Before starting the engine check that the oil level in the engine sump is correct see engine handbook 17 Section B To fit the Hatz engine refer to diagram B2 unless otherwise stated 6a Support the engine in position such that the drive adaptor pins locate in the engine clutch and with the bell housing location holes in line with those in the gearbox flange secure the bell housing to the gearbox using the 8 setscrews 617 Tighten the setscrews to a torque of 10 Ibs ft 1 3 kg m NOTE The handle clip 619 is secured to the gearbox flange using one of the s
59. n slacken back each nut half a turn Final adjustment should be made under operational conditions such that the rotor does not slip unless jammed by some obstruction CONTENTS Fault finding Lubrication and maintenance chart Maintenance Component Air cleaner Blades Chaincase Daily Gearbox Monthly Rotor clutch Weed cutters Weekly Wheels SERVICE BULLETINS APPERTAINING TO THIS SECTION ARE Bulletin No 61 Section G 66 62 CH EVERY 25 HOURS LUBRICATION AND MAINTENANCE CHART GE AT EER LUBRICATE THROTTLE CABLE SEAR CLUTCH AND SES ROTOR CONTROL PIVOTS HANDLEBAR SWIVEL AND Del CCU CHAAR SLIDE SHIELD HINGES DEPTH CONTROL MECHANISM EVERY IO HOURS OR TWICE DAILY IN VERY DUSTY CONDITIONS EVERY 25 HOURS CHECK AIR CLEANER OIL EVERY 25 HOURS CHECK CHAIN TENSION EVERY 25 HOURS CLEAN OUT SEDIMENT BOWL CHECK GEARBOX CIL LEVEL EVERY 250 HOURS DRAIN AND 26 FiLL GEARBOX EVERY 25 HOURS OIL DOG CLUTCH x AE gt WI la A ANS WZ EVERY 25 HOURS CHECK CHAIN CASE OIL LEVEL EVERY_250 HOURS DRAIN WASH OUT AND RE FILL CHAIN CASE EVERY IO HOURS EVERY 25 HORS EVERY IO HOURS WATCH FOR SIGNS OF UNDUE ROTOR CLUTCH SLIP ADJUST IF NECESSARY EVERY 25 HOURS CHECK TYRE PRESSURE 20 LBS PER SQ INCH GEARBOX DRAIN PLUG EVERY 250 HOURS EVERY 25 HOURS CHECK HUB NUTS FOR TiGeTNESS CmECK ALL BOLTS AND NUTS FOR TGRATNESS EVERY 25 HOURS O L ROTOR
60. nd the brass universal joint 391 The control tube and the rod can now be removed To fit the gear control tube and rod Locate the rear bracket 384 and gate 380 against the main frame and secure using the 2 bolts and nuts 41 Section D Locate the control rod and tube through the main frame and secure to the rear bracket by inserting the threaded trunnion through the bracket and secure using the flat washer and nut 385 Position the upper gear lever 370 through the gate and with the spring 378 in position in the upper lever position the two halves of the gear lever together and checking that the control rod eye bolt 387 locates through the lower lever secure to the flange on the control tube 389 using the pivot bolt 381 washer and nut 383 Fit and tighten the eye bolt nut 388 NOTE The nut 388 should be fully tightened then slackened back approx half a turn such that the eye bolt is free to rotate under operational conditions Check that the brass universal joint 391 slides freely on the 1st 2nd gear selector arm 392 and on the contro tube If not the location holes should be reamed out as necessary to produce free movement Locate the selector arm through the universal joint and position the control tube through the other hole Position the selector arm over the gearbox selector shaft and locating on key 394 tap the selector arm onto the shaft and tighten the selector arm setscrew 393
61. nto its location as shown in illustration C21 tllustration C21 NEXT Fit the wheel axle assembly as described in instruction 12 TO FIT THE WHEEL AXLE ASSEMBLY 12 Check that the differential lock selector 109 is straight and square and that it slides freely in its location in the gearbox case Remove from the gearbox and position the fork in the slot in the differential lock assembly 12a Position the axle assembly in the gearbox casing such that the differential lock selector locates in the gearbox and the pins of the differential lock locate through the back of the bullwheel While supporting the assembly as shown in illustration C22 tap the axle bearing into its location 12b With the aid of a piece of 1 OD tube tap the bearing 41 onto the end of the layshaft 50 and secure using special nut 39 and a split pin 33 Section C Illustration C22 NOTE When tightening the special nut the layshaft gears should be jammed using a suitable bar through the top inspection hole so that the gears cannot rotate 12c Fit the locknuts and trunnion shown in illustration C2 and refit the differential control quadrant NEXT Fit the axle bearing stop as described in instruction 13 and the gearbox cover as described in instruction 14 TO FIT THE AXLE BEARING STOP 115 13 Fit a new ollseal into the bearing stop and using metal shim or
62. nto the clutch drive plate studs and support the rotor in this position on blocks etc NOTE The side of the front shield will have to be levered out slightly to clear the dust cover when sliding the rotor onto the drive plate studs Ja Fit the sideframe over the rotor stub axle and secure to the main frame using the 2 frame bolts shown in diagram F1 Fully tighten these bolts and secure using 2 4 lengths of 16 swg locking wire 9b Fit and tighten the 5 setscrews F1 312 shown in diagram F1 together with the bolt F1 326 which secures the sideframe to the rear shield 9c Fit the locking tab 230 and nut 231 to the rotor stub axle Fully tighten the nut and secure by bending the tab washer over the nut 9d Fit the springs 214 and nuts 215 to the clutch drive plate studs and adjust the rotor clutch as described at the end of this section 9e Fit the depth control skid into its socket and lower the rear of the machine TO FIT THE CHAINCASE refer to illustration F6 on page 60 unless otherwise stated 10 Secure a new gasket to the chaincase using a smear of Hermatite Fit the chaincase to the backplate ensuring that the chain tensioner is positioned correctly such that the sliding block 193 will present the flat end towards the tensioner adjusting screw 194 Secure the chaincase to the backplate using the setscrews 184 two of which also secure the chaincase to the weed cutter br
63. r stub axle remove the oilscrew 232 from inside the right hand rotor end flange and using a long bar of 1 dia inserted through the rotor centre tube tap the stub axle from its location If the bearing 224 is to be replaced the stub axle may be pressed from the bearing using a workshop press The axle may then be pressed into a new bearing The oilseal 226 can be removed from its holder 225 with the aid of a 15 dia drift and a workshop press The new oilseal should then be pressed into the holder until flush with the edge Rotor stub axle to fit Position the back plug 236 hollow side outermost in the end of the rotor tube such that the threaded hole in the plug Is in line with the oil screw hole on the inside of the rotor end flange Using a 1 dia drift tap the plug into the rotor tube until the threaded hole in the plug is directly below the oil screw hole Fit and tighten the oilscrew 232 Using a soft headed hammer tap the stub axle and bearing into their location in the rotor centre tube Position spacer 227 through the oilseal 226 and fit the assembly over the stub axle and into the rotor centre tube flat side of the seal outermost Fit anew fibre washer 229 to the bearing cap 228 then fit and tighten the cap Remove the oilscrew 232 and lubricate the stub axle with a few strokes from an oil can replace and tighten the screw To fit the rotor assembly see instruction 9 53 Section
64. r to the out position checking that the differential lock and rotor dog clutch are completely disengaged Move the gear lever to the neutral position and release the engine clutch Final adjustments should be made under operational conditions 398 397 gt 405 406 L RL 428 401 403 402 tea QA Je A 432 tees 407 431 ae ke 394 433 li ustration D1 CONTROLS ASSEMBLY Keep this page open when referring to the instructions in section D 44 CONTENTS SERVICE BULLETINS APPERTAINING TO THIS SECTION ARE Subject Action DEPTH CONTROL WHEEL Assemble Dismantle FRONT SHIELD Fitting Removal MAIN FRAME Assemble Dismantle Fitting Removal REAR SHIELD Fitting Removal TRAILING BOARD Fitting Removal TOOLS LIST Wo off BSW Open ended spanner AT BSW Ring spanner 3 BSW Open ended spanner AT BSW Ring spanner BSW Ring spanner 2 BSW Ring spanner BSW Ring spanner 2 BSW Ring spanner AF Ring spanner Cold chisel Small punch Copper Rawhide mallet 1lb Ball pein hammer Pair 6 engineers pliers Medium screwdriver h m sesch sesch sch sesch sach sach sch d d d gt gt SPECIAL EQUIPMENT Sampson C 110 glue Container tray Self grip wrench 2ft long straight edge 45 Section E Section E TO REMOVE TO REMOVE All illustration numbers in this section refer to illustration E4 on page 50 unless othe
65. right hand side of the machine 2 To fit the front shield see instruction 5 TO DISMANTLE REMOVE THE MAIN FRAME 275 3 Remove the rear and front shields as previously described in instructions 1 and 2 then proceed as follows 3a Remove the engine throttle control from the machine handlebars together with any cabie clips On Kohler models remove the air cleaner assembly by removing the hose and releasing the securing boits 3b Disconnect the clutch hand lever to pivot lever rod shown in illustration E2 by removing the split pin 439 Illustration EA Section E 3c 3d 3e 3f 3g 3h 3j Remove the gear control rods and selector gate rotor control and differential lock quadrant gear selector interlock mechanism and the clutch rods as described in Section D Remove the depth skid socket 278 by removing the 2 bolts 291 which secure the socket support stays to the main stay tube 304 Remove the split pin 272 and special nut 271 from the handlebar pivot block and bolts 264 from the handlebar slide 263 and remove the handlebars Disconnect the fuel line from the fuel tank and empty tank on Hatz model remove the small injector pump spill pipe from the top of the tank Remove the nuts 362 and washers 361 from the U bolts 360 and remove these U bolts and the fuel tank Remove the tool box 273 starting handle 305 and depth control a
66. rm 280 Remove the chain tensioner adjusting screw and the special frame bolt behind it Also remove the bolts which secure the jackshaft housing to the gearbox case and the frame bolt from the top of the backplate so that the backplate assembly may be removed complete Remove the locking wire from the main frame to gearbox bolts 316 and remove these bolts and the bolts 315 which secure the frame to the front of the gearbox The main frame can now be removed TO FIT ASSEMBLE THE MAIN FRAME 275 4 4a 4b Locate the main frame on the front of the gearbox using the setscrews 315 but do tighten these setscrews at this stage otherwise the frame may become distorted making it difficult to fit the remaining frame securing setscrews Locate and secure the back of the main frame using the setscrews 316 Fully tighten and lock using a 40 long piece of 16 swg wire The front setscrews 315 can now be fully tightened Fit the backplate assembly complete using the 4 jackshaft housing to gearbox case securing bolts and the frame bolt at the top of the backplate Lock the frame and jackshaft housing bolts using 16 swg wire Fit the special frame bolt located on the bottom edge of the chaincase then fit the chain tensioner adjusting screw NOTE The chain tension should be adjusted as described at the end of Section sed Ac 4d 4e 4f 4g Fit the tool box 273 starting handle 305 and depth control
67. rter dog bearing housing 21 and remove the housing complete with its gasket and starter dog 19 4b Remove the setscrews 26 and spring washers 27 from around the perimeter of the gearbox case 4c With the aid of a flat bladed screwdriver prise the gearbox cover from the main gearbox casing The cover is located on 2 dowel pins and may be difficult to move at first Reverse idler gear assembly to remove Having removed the gearbox cover as previously described proceed as follows Remove the 2 BSF philidas nut 38 and the flat washer from the reverse idler pin 34 Withdraw the idler pin from its location in the gearbox cover complete with the reverse idler gear 35 If the idler gear bush 36 is to be replaced it should be pressed out with the aid of a dia soft brass drift The new bush may then be pressed into the reverse gear until flush with the gear faces Two dia oil holes should then be drilled in the bush working through the existing holes in the idler gear The bush will then have to be reamed to a diameter of 0 627 0 629 to remove the burrs caused by drilling and to ensure correct bore size Reverse idler gear assembly to fit Insert the idler pin 34 through the idler gear 35 so that the smaller 12 tooth gear is against the head of the pin Locate the pin in the gearbox cover and secure using the flat washer 37 and philidas nut 38 Wheel axle oilseal 90 The w
68. rwise stated THE REAR SHIELD 325 1 Support the rear of the machine such that the rotor assembly and depth control skid are well clear of the ground then proceed as follows la Remove the depth control skid 279 or depth control wheel where fitted by releasing the spring clip 281 and moving the depth control arm 280 to the right allowing the skid to slide out of the socket 278 1b Remove the locknuts 331 spring and flat washers from the clamping bolts 328 each side of the rear shield and remove the bolts 1c Remove the setscrew 326 and spring washer 327 from each side of the rear shield pivot tube 1d Remove the shield by lifting upwards and sliding back over the rotor Trailing board 337 The trailing board is easily removed from the rear shield by removing the locknuts 333 from the hinge bar 332 and withdrawing the bar Fitting the trailing board is the reverse to the removal procedure Depth control wheel to dismantle Remove the wheel cap 353 and release and remove the locknut 345 from the tab washer 346 Slide the wheel assembly from its location in the arm 342 Remove the outer dust cover 347 and withdraw the axle Remove the wheel bush 348 and inner dust cover 349 Depth control wheel to assemble Position the wheel bush 348 through the inner dust cover 349 and locate through the wheel centre Slide the axle through the bush from the opposite side to the dust cover
69. s necessary by means of the locknut 457 Lift the hand lever and return the gear lever to the neutral position Rotor dog clutch adjustment Remove the split pin 418 from the differential control rod 417 and move the rod aside Adjust the effective length of control rod 410 by means of the locknut 413 such that the dog clutch is fully engaged when the hand lever 406 is moved to the in position Check that the dog clutch disengages completely when the hand lever is moved to the out position 43 Section D Position the differential lock control rod 417 through the block on the rotor control rod and secure using a split pin Differential lock adjustment Support the machine such that the wheels are clear of the ground and secure the engine clutch in the disengaged position Check for obstructions dirt stonesetc behind the differential lock quadrant otherwise the movement of the differential lock selector will be restricted Position the hand lever 406 in the out position select 1st gear and while turning over the gearbox internals by means of the starting handle adjust the effective length of control rod 417 using locknut 421 on the end of the rod Additional adjustment is provided by the locknuts 427 and trunnion 426 on the differential lock selector LL Move the hand lever to the in position and check that the differential lock engages fully Move the hand leve
70. shaft proceed as follows Remove the split pin and special nut from the front of the pinion and using a workshop press push the shaft from the pinion and bearing as shown in illustration B 8 To reassemble The shaft can be pressed into the bearing and the pinion replaced and secured by the special nut and split pin To remove the bearing from a clutch shaft where the drive pinion is an integral part of the shaft proceed as follows Working from the back of the pinion carefully support the outer cup of the bearing and using a workshop press push the shaft from the bearing as shown in illustration B9 The shaft can then be pressed through the new bearing until the bearing is against the shoulder at the back of the drive pinion Illustration B8 Illustration B9 press head i clutch shaft and integral 7 tooth pinion 9 tooth pinion AE bearing 15 Section B TO FIT THE CLUTCH SHAFT 4 Position the clutch shaft assembly through the oilseal hole in the clutch housing allowing the pinion end of the shaft to drop slightly to avoid the clutch operating pawi 4a Place the retaining circlip on the clutch shaft and using a pair of circlip pliers ease the circlip through the oilseal hole in the clutch housing and allow it to slide up to the pinion 4b Using a soft headed hammer tap the end of the clutch such that the bearing slides into its location NOTE When tapping the bearing into its
71. split pin 176 NOTE If a new jackshaft has been fitted an dia hole will have to be drilled through the jackshaft to accept the split pin Ensure all swarf is removed from sprocket after drilling NEXT Fit the rotor clutch as described in instruction 8 TO FIT THE ROTOR CLUTCH refer to illustration F6 unless otherwise stated 8a 8b Position the spacer 205 on the rotor drive shaft sprocket and through the oilseal 204 Position the drive plate 209 over the rotor bearing housing and slide the rotor disc 211 onto the splines of the shaft and up to the drive plate Fit the flat washer 206 and special nut 207 to the drive shaft and with a thin bar or screwdriver blade inserted through the links of the drive chain to prevent the drive shaft sprocket from rotating fully tighten the special nut 207 and secure using a split pin 208 58 Section F NOTE Care should be taken when tightening the special nut to avoid bending the backplate 8c Fit the wearing plate 212 over the drive plate studs and slide up to the rotor disc 211 NEXT Fit the rotor assembly as described in instruction 9 TO FIT THE ROTOR ASSEMBLY refer to illustration F7 on page 60 unless otherwise stated 9 Position the rotor assembly such that the right hand end blades are parallel to the bottom edge of the shield and with the slot of the dust cover 237 positioned at the bottom slide the rotor o
72. t 1 Ib Ball pein hammer Large screwdriver Special tool 2 Special tool S 6 Section C Section C ROAD WHEELS Each road wheel fitted with a 4 00 x 12 2 ply traction tread pneumatic tyre is mounted on a hub which incorporates a friction clutch device These are adjusted so that the wheels have sufficient grip to pull the machine but will slip if they become jammed by an obstruction between the wheels and the frame Single wheels are fitted as standard on the 20 and 24 models and twin wheels on the 30 model Twin wheels may be fitted to the 20 machines if required but NOT to 24 models as the chaincase prevents the fitting of the second wheel on the left hand side of the machine Unless otherwise stated all the illustration numbers in this section refer to illustration C25 which can be found at the end of this section on page 36 TO REMOVE THE WHEELS 1 With the machine suitably supported on blocks etc proceed as follows la Remove the wheel nuts 84 springs 85 and the wheel hub disc 88 and remove the wheel On 30 models remove the extension hub 130 and then the inner wheel Removal procedure is the same for left and right hand wheels To refit the wheels see instruction 16 TO REMOVE THE WHEEL HUBS Illustration C 1 2 Remove the wheels as previously described in instruction 1 then proceed as follows 2a The right hand wheel hub 89 is secured to the wh
73. t ream out to give sliding fit If worn replace inspect gears and replace as necessary Fault Difficulty in engaging or disengaging the differential lock Difficulty in engaging the rotor Excessive jumping of machine Erratic rotation of the rotor Excessive blade wear Clogging of the rotor Machine does not move forward Possible Cause incorrectly adjusted differential lock control differential lock selector fork seizing in gearbox rotor dog clutch not adjusted properly rotor dog clutch operating arm loose or locating key worn rotor dog clutch selector seized in selector housing blades fitted wrongly rotor dog clutch not engaging fully rotor clutch slipping incorrect drive chain tension bent blades incorrectly adjusted weed cutter blades or bent blades wheel friction clutches incorrectly adjusted 67 Remedy adjust to correct setting free and lubricate If bent straighten or replace adjust to give full engagement of the dogs tighten operating arm securing bolt and or replace the locating key free and lubricate then adjust to correct setting check that blades are of the correct type i e left or right handed Section G See Section F amp G adjust to give full engagement of the dogs adjust to correct setting adjust drive chain tension replace adjust to correct setting replace bent blades adjust to correct setting pn 4
74. te with the starting dog 19 and secure using the setscrews 22 NEXT Fit the right hand wheel and hub as described in instructions 15 and 16 TO FIT THE WHEEL HUBS 15 Position the left hand wheel hub 118 over the wheel axle and secure using the washer 119 and special nut 120 Fully tighten the nut and lock using a split pin 121 The right hand wheel hub 89 is secured by a special hub nut 87 which should be fully tightened TO FIT THE WHEELS 16 Position the wheel over the spigot on the wheel hub if double wheels are fitted slide the extension hub over the wheel studs and up to the wheel centre then fit the second wheel over the spigot on the extension hub 16a Fit the wheel hub disc 88 over the wheel studs and secure with the springs 85 and nuts 84 35 Section C WHEEL FRICTION CLUTCHES Tighten the wheel nuts so that the springs are fully compressed then slacken back each nut half a turn This will ensure that the safety clutch device will operate correctly Should the wheel hubs slip when the machine is in normal use tighten the wheel nuts evenly until sufficient grip is acquired to produce forward movement of the machine TYRES Check that the tyre pressure is correct 20 psi 1 4 kg sq cm and that the tyres are in good condition Adjustments to the gear selectors and the differential control should be made as described in section D ADJUSTMENTS This illust and c
75. the engine by releasing the small clamp bolt and cable clamp on the side of the engine 1b Slacken the jubilee clip on the carburettor induction elbow end of the air cleaner hose 595 and remove the hose from the elbow 1c Disconnect the stop switch cable 573 from the engine mounted condenser 1d Turn off the fuel supply from the petrol tank at the fuel filter bowl and disconnect the pipe from the tank Drain off any fuel in the pipe before removing from the engine le With the engine suitably supported on blocks etc remove the 8 setscrews 558 from around the perimeter of the clutch bell housing 556 The machine may then be moved clear of the engine TO FIT THE ENGINE See instruction 6 TO REMOVE THE DRIVE ADAPTOR 551 KOHLER ENGINE To remove the drive adaptor from the engine crankshaft remove the square plug 557 from the side of the bell housing 556 and loosen the square headed setscrew 554 using an extended 2 square box spanner through the hole in the side of the housing Slide the adaptor from the housing and retain the locating key 555 and spacer if fitted If the drive adaptor bearing 553 is to be renewed the old bearing may be pressed out from the back of the adaptor with the aid of a 1 dia drift The new bearing can then be pressed into its location greased and secured by positioning the special washer 552 over the bearing domed side outermost and with the aid of a small punch
76. tion When ordering spare parts DO NOT confuse the illustration numbers used in this manual with the TRUE part numbers found in the official parts list form number L 693 While every effort is made to ensure that the information contained within this manual is correct any errors which may occur should be brought to the attention of our Service Department INDEX SECTION PAGE Specifications torque loadings special tools A 3 Engine removal clutch clutch shaft air cleaner B 7 Gearbox wheels and hubs C 19 Controls D 37 Main frame handlebars shields E 45 Rotor rotor clutch drive chain backplate F 51 Lubrication maintenance and fault finding G 61 Although this manual refers to machines in current production reference is made where possible to the history of the various assemblies and components ILLUSTRATION REFERENCE The figures in brackets after component names refer to the illustration number of the component within the diagram specified by that instruction e g C25 35 is Section C illustration 25 illustrated component 35 Reverse idler gear Howard Gem HISTORY OF THE GEM SERIES I SERIES H The HOWARD GEM has been developed over a period of many years Since its introduction in 1942 there have been five series of GEM each series being an improved version of its predecessor The original GEM was fitted with bicycle type handlebars but was not equiped with either a differenti
77. unbroken shaft and this method of removal is described below Should the clutch shaft be broken within the gearbox see section C instruction 7 for an alternative method of removal 3 Remove the engine and engine clutch as previously described in instruction 1 and 2 then proceed as follows 3a Drain the oil from the gearbox a container of at least 6 pints capacity will be required 3b Remove the special oilseal and the clutch thrust sleeve from inside the clutch housing NOTE The oilseal may have to be levered from the flange as it will have been sealed to the gearbox using Hermatite 3c Remove the gearbox top inspection cover and with a pair of right angled circlip pliers remove the 2 internal circlip from the pinion bearing housing as shown in illustration B6 NOTE It may be necessary to gently tap the end of the clutch shaft using a soft headed hammer until the bearing is clear of the circlip The ears of the circlip should be at the top of the housing if not turn the circlip into this position The circlip on removal from its location will not drop into the gearbox but will remain suspended on the clutch shaft 3d Place a 3 long piece of 2 2 o d tubing over the end of the clutch shaft and by means of washers and the clutch securing nut on the thread of the clutch shaft draw the shaft out in stages as shown in illustration B7a adding more washers as necessary unt
78. urn the jackshaft backwards and forwards and using a dial test indicator check the total backlash as shown in illustration C20 If the backlash is not correct the clutch shaft and the jackshaft will have to be removed so that shim may be added to decrease backlash or removed to increase backlash from behind the jackshaft bearing The jackshaft and the clutch shaft should then be replaced and the backlash rechecked Refer to instructions 9b to 9f inclusive for the sequence of assembling the jackshaft 32 Section C 10c Check that the clutch shaft bearing retaining circlip 63 has been fitted and that the jackshaft assembly is complete then slide the thrust bearing 65 onto the clutch shaft and up to the operating pawl 10d Position the thrust sleeve 66 through the special oilseal 68 taking care not to damage the rubber lip of the seal Apply a small amount of Hermatite around the locating flange of the oilseal Locate the thrust sleeve over the clutch shaft and secure the oilseal to the main gearbox case using the 3 screws 69 10e Refit the engine clutch and engine as described in section B NEXT Fit the layshaft assembly as described in instruction 11 TO FIT THE LAYSHAFT 11 Fit the layshaft bearing stop 54 complete with gasket 53 and secure using the 3 setscrews 56 11a Position the layshaft and bearing assembly and using a soft headed hammer tap the assembly i
79. ver axle bearing stop axle assembly top inspection cover and the dipstick as previously described then proceed as follows Remove the bull pinion 43 small gear 44 and spacer 46 from the layshaft and retain any shims which may have been fitted Remove the bearing stop 54 from the gearbox casing and while supporting the layshaft by hand tap the layshaft from its location Remove the medium gear 48 and large gear 49 If the layshaft bearing 51 is to be renewed a universal puller should be used as shown in illustration C9 The shaft can then be pressed into the new bearing using an ordinary workshop press universal bearing pulier bearing 51 layshaft TO ASSEMBLE THE LAYSHAFT Position the large gear 49 and medium gear 48 on the layshaft The combined width of these gears should be 1 Add shims 47 between the two gears until this measurement is achieved Position the spacer 46 on the layshaft against the medium and large gears The small gear 44 should be wide and shims 45 should be placed against the spacer 46 as necessary to achieve this measurement Fit the small gear and bull pinion onto the layshaft To refit the layshaft see instruction 11 26 Section C TO REMOVE THE CLUTCH SHAFT 7 If the clutch shaft is to be removed without dismantling the gearbox follow the method described in section B instruction 3 However if the clutch shaft is brok

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