Install mounting plate B. Vi. 1581 on a Desvil rack.
Install the gearbox on mounting plate B. Vi. 1581.
Remove the clutch release cylinder.
Loosen the bolts located inside the crankcase.
Remove the rear cover. It must be removed along the horizontal axis of the box, as it includes a lubricant capsule located in the input shaft bore.
Engage first gear with the shift lever, and fifth gear by sliding its fork along the stem.
Turn out a bolt of a secondary shaft and turn away a nut of an input shaft.
With the help of B. Vi. 31-01 (core), knock out the fifth gear fork pin.
Remove the fork and fifth gear clutch.
Remove the fifth gear hub using tool B.Vi. 1170.
Install the B.Vi gear clutch. 1170 to the 5th gear position by turning it so that the splines of the gear coupling and the hub are aligned, and remove the tool with the hub.
Remove the 5th gear fixed gear using tools B.Vi. 22-01 and B. Vi. 1000.
Remove the outer crankcase bolts.
Remove speed sensor B (for semi-automatic transmission JH1).
It is recommended to install two magnets or block holes C in order not to lose the balls and springs for fixing the stems ½ and 3/4.
Remove reverse stem A and reverse contactor B.
Press on the shift rod with a force directed outward.
Disconnect and remove the box crankcase.
Rotate the reverse axle assembly to the left and remove the shift fork stem «reverse / fifth gear».
Raise the input shaft slightly and remove the reverse gear axle assembly.
Disconnect the 3/4 yoke pins using tool B. Vi. 949 and remove the 3/4 stem and yoke assembly.
At the same time, remove the input and output shaft assembly with the stem and ½ yoke.
Remove pins A and B.
Removing gears
Clamp the output shaft in a vise with jaws, and then remove all gears.
When removing and installing circlips, use circlip pliers on one side and pliers on the other.
Checking details
Gear and clutch teeth must not be excessively worn and must not have any nicks.
Also, make sure that the shaft surfaces and the inner surfaces of the gears do not show signs of friction or excessive wear.
It is recommended to mark the position of the gear couplings relative to the hubs.
Gear group installation
Install in the reverse order of removal.
Retaining rings must be systematically replaced.