Contents: Disassembly ↳ Assembly ↳
Housing of a mechanical five-speed gearbox
1 – front part of the crankcase; 2 – middle part of the crankcase; 3 – rear part of the crankcase; 4 – lid; 5 – Clutch release bearing guide sleeve; 6 – crankcase gaskets; 7 – Reverse light switch
Removal the five-speed gearbox cover
The arrow shows the location of the spring locks that hold the gear engaged.
Disassembly
1. Remove the release bearing and clutch release forks.
2. Unscrew the four bolts securing the clutch housing to the front of the gearbox housing.
3. Remove the sealing ring from the rear of the gearbox housing (tool 21.051).
4. Remove the rear part of the gearbox housing ring (tool 16.025).
Please note: This ring can only be replaced together with the rear part of the gearbox housing and the secondary shaft (set).
5. Remove the front cover of the gearbox housing.
6. Engage 1st gear and knock out the selector mounting pin.
7. Remove the 5th gear spring lock plate, spring and pin.
8. Remove the rear part of the gearbox housing.
9. Insert one bolt to hold the middle part of the gearbox housing in place.
10. Unscrew the bolt and pin of the selector shaft spring lock.
11. Remove the selector shaft.
12. Remove the fork assembly, selector and spring locks.
13. Remove the 5th gear synchronizer retaining ring on the secondary shaft and move the entire synchronizer back.
14. Engage two gears simultaneously (to lock the gearbox) and unscrew the nut securing the 5th gear on the intermediate shaft.
15. Using a rod, push back the intermediate shaft gear block axle. The rod should be in constant contact with the intermediate shaft gear block axle to prevent the bearing needles from falling out.
16. Attach the fixture to the front of the transmission housing.
17. Remove the 5th gear pinion from the intermediate shaft using tool 16.033
18. Insert the intermediate shaft gear block axle back into its original place, pushing out the axle of the 16.033 device by hand.
19. Remove the retaining ring of the gear block bearing in the middle part of the gearbox housing.
20. Remove the bearing spacer sleeve.
21. Disengage both previously engaged gears.
22. Unscrew the bolt holding the middle part of the gearbox housing by 6–7 mm and move the middle part of the housing away.
23. Press the gear block bearing deep into the middle part of the crankcase using two thin screwdrivers (1 and 2) and remove the outer bearing ring (3 – bolt).
24. Move the gear block axle back enough to allow the gear block to be removed from the crankcase.
25. Place the intermediate shaft gear block on the bottom of the front part of the gearbox housing.
26. Remove the clutch release bearing guide sleeve and take out the input shaft.
27. Remove the secondary shaft together with the middle part of the crankcase.
28. Using the appropriate puller (large diameter sleeve, M8Ch60 bolt together with nut), remove the axle of the intermediate gear of the reverse gear.
29. Remove the retaining ring and the reverse gear lever shaft.
Assembly
1. Before assembly, wash and check the condition of bearings, synchronizers and gears.
2. The gearbox assembly is performed in the reverse order of its disassembly. During installation, pay attention to the following steps.
3. Lubricate the bearing needles of the intermediate shaft gear block with consistent bearing grease and correctly position them on the axle that forms the internal raceway.
4. Using tool 16.033, install the 5th gear pinion on the intermediate shaft. The spacer sleeve on the pinion side must be coated with grease to ensure free rotation of the pinion.
5. The threads of the bolts screwed into the through holes of the crankcase should be coated with a suitable sealant before installation.
6. Before tightening the rear part of the gearbox housing, the operation of the gearbox should be checked (the ability to engage individual gears and free rotation of the shafts).