Note: When replacing parts that directly affect the position of the main drive pinion (tapered roller bearings, the main drive pinion itself or the gearbox housing), and also if there is no marking on the driven gear of the deviation "g" from the nominal position of the driving gear, before starting to disassemble the gearbox, measure the value "r" as indicated below.
The arrow shows the gearbox marking
Drain the oil from the gearbox housing, clean the gearbox and install it on the assembly table.
Remove the gear selector lever.
Remove the gear selector shaft assembly.
After unscrewing the mounting bolts, separate the gearbox housing from the clutch housing.
Separating the gearbox housing from the clutch housing
Remove the plastic plug from the rear gearbox cover using a screwdriver.
Clamp the input shaft in a vice with soft metal pads and remove the hex bolt from the rear end of the input shaft.
Clamp the gearbox housing in a vice.
Remove the bolts securing the rear gearbox cover.
Remove the rear cover of the gearbox housing, moving it with a plastic mallet if necessary, and remove the first inner race of the primary shaft ball bearing.
Using a two-lever puller, remove the toothed carriage 2 (see photo) of the 5th gear engagement together with the second inner ring 1 of the primary shaft ball bearing, then remove the locking ring 3 of the 5th gear synchronizer.
Removal the V-gear synchronizer tube carriage
Knock out the spring pin from the 5th gear fork without damaging the fork rod socket in the crankcase wall.
Remove the 5th gear synchronizer sliding sleeve retaining ring from the primary shaft.
Removal 5th gear parts: 1 - second inner bearing ring; 2 - toothed carriage for engaging the 5th gear; 3 - V gear synchronizer locking ring; 4 - intermediate reverse gear lever mounting bolt
Remove the 5th gear sliding gear together with the sliding sleeve, hub, needle bearing and 5th gear engagement fork.
Remove the stop bolts 1 (see photo) of the fork rods.
Thrust bolts 1 of the fork rods and hexagon bolt 2 of the rear end of the secondary shaft
Clamp the 4th gear of the secondary shaft in a vice with soft metal pads and unscrew the hex bolt 2 from the end of the secondary shaft.
Press the 5th gear off the secondary shaft using a Kukko 20/10 type lever puller.
Remove the V gear adjusting washer.
Secure the gearbox housing in a vice with pads made of some material.
Knock out the spring pin from the 1st and 2nd gear shift fork rod linkage while holding the fork rod with a hammer.
Removal the spring pin from the 1st and 2nd gear shift fork rod link
Turn the rod leash upward.
Knock out the spring pin from the III and IV gear shift fork. Remove the III and V gear fork rod. Remove the push rod and the retainer spring.
Remove the intermediate reverse gear lever mounting bolt.
Slightly extend the primary and secondary shafts out of the gearbox housing.
Remove the primary shaft together with the shift fork for III and IV gears.
Disconnect the reverse spring latch from the secondary shaft side and move it to the side. Remove the reverse lock.
Extend the secondary shaft so that the rod and the fork for shifting 1st and 2nd gears can be removed
Remove the secondary shaft by turning it around the axis.