Gearbox housing unit
1 – front part of the crankcase (clutch housing); 2 – intermediate bearing plate; 3 – middle part of the crankcase; 4 – back cover; 5 – oil level check plug; 6 – centering sleeve of the intermediate bearing plate; 7 – release bearing guide sleeve
Gearbox gear and shaft assembly
1 – primary shaft; 2 – secondary shaft; 3 – reverse gear pinion axis; 4 – reverse gear; 5 – synchronizer hubs; 6 – synchronizer sleeve stopper; 7 – synchronizer bushing balls and springs; 8 – synchronizer rings; 9 – spring retaining rings; 10 – 1–2 gear synchronizer sleeve; 11 – 3-4 gear synchronizer sleeve; 12 – 5th gear synchronizer sleeve; 13 – bearings of secondary and primary shafts; 14 – plate; primary shaft bearing retainer; 15 – plate; secondary shaft bearing protector; 16 – support pad; 17 – 5th gear needle bearing; 18 – secondary shaft nut; 19 – differential box with main gear drive pinion; 20 – axle gears; 21 - satellites; 22 – satellite axis; 23 – differential basket; 24 – differential bearings; 25 – differential sealing rings; 26 – speedometer drive worm gear wheel; 27 – gear with speedometer drive shaft
The black circles show the gear numbers (AR – reverse gear).
1. At the front of the gearbox, remove the clutch release bearing.
2. Remove the speedometer drive shaft by unscrewing the bolt that secures it to the gearbox housing.
3. Place the gearbox with the front part of the crankcase on a holder of the appropriate height (minimum 80 mm).
4. Remove the rear part of the crankcase by unscrewing the corresponding mounting bolts.
5. Remove the cotter pin securing the 5th gear forks.
6. Engage 5th gear by moving the synchronizer sleeve.
7. Engage 2nd gear to lock the gearbox shafts.
8. Unscrew the nut at the end of the secondary shaft.
9. Set the gear shift mechanism to neutral position.
10. From the end of the secondary shaft, remove the synchronizer unit (hub-sliding sleeve) of 5th gear together with the forks, without disconnecting the synchronizer hubs from the sliding sleeve.
11. Remove the 5th gear from the secondary shaft together with the raceway, needle bearing and support pad.
12. Remove the sealing ring, spring lining and 5th gear from the end of the primary shaft.
13. Remove the two plates securing the primary and secondary shaft bearings by unscrewing two mounting screws.
14. Remove the middle part of the gearbox housing by unscrewing the corresponding bolts connecting it to the front part of the housing (clutch housing).
15. Remove the axle, bushing and reverse gear.
16. Press your finger on the reverse gear forks at the height of their axle, remove the axle of the forks and the reverse gear forks.
17. Knock out the cotter pin from the selector shaft, pull out the shaft and its seal.
18. Remove the selector axle spring with two linings, as well as the selector with the sleeve.
19. Remove the gear assemblies with both shafts, as well as the fork assembly with axles, from the crankcase upwards.
20. Remove the intermediate bearing plate by unscrewing the corresponding bolts connecting it to the front part of the crankcase (clutch housing).
21. Remove the cotter pin and reverse fork lock spring from the front of the gearbox housing.
22. Remove the differential.
23. Remove the gear selector lever assembly from the front of the crankcase by knocking out the cotter pin from the outer gear selector lever and removing it, remove the seal and the inner lever together with the lever assembly axle.
24. Knock out from the front of the crankcase (clutch housing) differential seal ring and remove the four centering bushings.
25. Remove the outer race of the differential tapered bearing.
26. Remove the release bearing guide bushing bolts from the front of the crankcase (clutch housing) and remove the bushing together with the gasket.
27. Remove the differential seal ring and the outer ring of the differential tapered bearing from the middle part of the gearbox housing (second differential bearing).
28. Clean the connecting surfaces of the crankcases.