Check the condition of the front coupling gear teeth. They must not be damaged in any way and must have sharp edges.
The idle gears must rotate freely on their shafts.
The idle gears must have a minimum axial clearance of 0.10 mm/0.0039 in.
The idlers for the 3rd and 4th gears on the secondary shaft must have a maximum axial clearance of 0.25 mm/0.0098 in.
When refitting, make sure the circlips are positioned correctly. Check the state of wear of the roller half bearings.
The threading and the splining of the shafts must be in perfect condition.
Note. For correct functioning of the gearbox, refer to the recommended dimensions indicated in the diagram below.
Also check that the parts containing the gear coupling mechanism are in good condition (see exploded diagram).
Engage the gears and check that the gearbox control does not jam (selector fork-gear groove and fork pin-desmodromic drum groove) due to incorrect axial clearance.
Correct the clearances by shimming the gearbox shafts and drum with the shims.
- Total gearbox shaft axial clearance: 0.25 mm/0.0098 in.
- Total gearbox drum axial clearance: 0.25 mm/0.0098 in.
