Disassembly and assembly of the gearbox

The shafts of the RK5 manual transmission are shown in Fig. 5.34, the shafts of the RK6 manual transmission are shown in Fig. 5.35.

Disassembly

1. Install the bracket plate B. Vi. 1417 on the Desvil rack.

2. With the B. Vi 1417 bracket in a horizontal position, place the gearbox with the side normally facing the engine on the plate (Fig. 5.36).




3. Fasten the gearbox to the bracket B.Vi.1417 using holes No. G2 and Z2 (Fig. 5.37).



4. Disconnect the nipple C of the clutch release drive slave cylinder by removing the retainer 3 (Fig. 5.38).



5. Unscrew the three bolts B securing the hydraulic drive slave cylinder, and then remove the cylinder itself (Fig. 5.39).




6. Remove the selector lever 1, the drive cable bracket 2 and the reversing light switch 4 (Fig. 5.40).



7. Unscrew the bolts securing the gearbox wiring connector.

8. Rotate the shift lever to release the control lever, while lifting the crankcase up, and then remove the crankcase completely (Fig. 5.41).

Caution! Save the adjusting washer A of the selector block (fig.5.42). It gets close to the block and can remain glued to the gearbox housing.

9. Rotate the control unit, disengaging the spring at the top of the return sleeve, and remove the unit by pulling it upwards (Fig. 5.43).



10. Remove the axle and reverse clutch assembly B, then the 3rd/4th gear fork C (Fig. 5.44).




11. Remove the 1st/2nd and 5th/6th gear synchronizers and the short secondary shaft (Fig. 5.45).



12. Remove the long secondary shaft assembly with the fork and the primary shaft (Fig. 5.46).



13. Remove the gear (Fig. 5.47).

Removing gears (long secondary shaft)

14. Disconnect the snap ring (Fig. 5.48).

Note: To remove the snap ring, it is necessary to break the bearing separator.

15. Remove the assembly using a press «ring-gear-coupling», resting the puller under the 2nd gear (Fig. 5.49).



16. Remove the assembly using a press «ring-gear-coupling», placing the device B. Vi. 1510-01, index L and a puller under the 6th or 5th gear depending on the type of gearbox (Fig. 5.50).



17. Place a rag inside the device, at the bottom, to soften the fall of the shaft after it is removed.

Removing gears (short secondary shaft)

18. Disconnect the snap ring (Fig. 5.51).

Note: To remove the snap ring, it is necessary to break the bearing separator.

19. Remove the assembly using a press «ring-gear-coupling», placing device B. Vi. 1510, index L under the 3rd gear (Fig. 5.52).



20. Place a rag inside the device, at the bottom, to soften the fall of the shaft after it is removed.

Removing and installing bearings

21. Remove the bearings with a press using a puller (Fig. 5.53a, b).





22. Install the bearings using tool B. Vi. 1510-01, index O (Fig. 5.54a, b).





23. Remove the bearings with a press using a puller (Fig. 5.55)



24. Install the bearings using tool B. Vi. 1510-01, index M (Fig. 5.56).

Assembly

25. The teeth of the gears and couplings must not have any nicks or excessive wear. Also check that the shaft surfaces and the inner surfaces of the gears are free from friction and excessive wear. It is advisable to mark the position of the toothed couplings in relation to the hubs. Bearings must be replaced as soon as scratches or hot spots become visible, or in case of excessive wear.

Installing gears

Caution: Replacing components such as gear bushings and hubs requires changing the installation order below.

26. Measure the height of the part being replaced and the part being installed. If the difference between the dimensions of the two parts exceeds 0.025 mm, it is necessary to adjust the installation gasket. By increasing its thickness if the new part is lower than the old one, or by decreasing its thickness if the new part is higher than the old one.

Table 5.1 provides an example of calculating the value of a new installation gasket, which should be determined after replacing the bushings under the gears or hubs.

Table 5.1. Example of calculating the value of a new installation gasket, which should be determined after replacing the bushings under the gears or hubs

Detail	Replaceable part	New detail	Difference
Replacing rings or hubs on a long secondary shaft
Bushing under the 6th gear pinion	A	A	-
Hub (5/6)	b	IN	-
Long 2nd gear ring	With	WITH	-
Hub (1/2)	d	D	-
Pad	X	X = x± (a-A) ± (b-B) ± (s-s) ± (d-D)	-
Replacing rings or hubs on a short secondary shaft
Bushing under the 4th gear pinion	A	A	-
Bushing under the reverse gear	b	IN	-
Hub (3-4)	With	WITH	-
Reverse hub	d	D	-
Pad	X	X = x± (A-a) ± (B-b) ± (S-s) ± (D-d)	-

Example: Replacing the bushing under the reverse gear of the short secondary shaft

Detail	Replaceable part	New detail	Difference
Bushing under the 4th gear pinion	A	A
Bushing under the reverse gear	Ь (30.802)	IN (30.830)
Hub (3-4)	With	WITH	+ 0.028
Reverse hub	d	D
Gasket Result	2.10	X = x± (A-a) ± (B-b) ± (S-s) ± (D-d) x = 2.10 - 0.028 = 2.028

Knowing that shim thicknesses range from 0.020 to 0.20, in this example you would select a shim with a thickness of 2.02.

Installing the Long Secondary Shaft Gears

27. Install needle bearing A, 6th gear gear B and its synchronizer ring (Manual transmission RK6) (Fig. 5.57). Using tool B. Vi. 1510-01, index N, fit the hub of the 6th/5th gear toothed clutch C (align the hub recesses with the synchronizer ring recesses so that they match). Using the tool B. Vi. 1510-01, index N, fit the 5th gear D sleeve (ensure a pressure of 5 tons at the end of pressing).



28. Install the needle bearing E and the 5th gear pinion, as well as its synchronizer ring F (Fig. 5.58). Install the shaped washer G. Using the device B. Vi. 1510-01, index N, fit the sleeve of the 2nd gear H (ensure a pressure of 5 tons at the end of pressing).



29. Install needle bearing I, 2nd gear J with three-cone synchronizer rings installed (Fig. 5.59).

Attention! Correctly position the notches of the three-cone synchronizer (Fig. 5.60).

30. Using tool B. Vi. 1510-01, index N, fit the hub of the 1st/2nd gear toothed clutch K, align the recesses of the hub with the recesses of the synchronizer ring so that they coincide (Fig. 5.61). Using the device B. Vi. 1510-01, index N, fit the sleeve L of the 1st gear pinion (with the pin holes facing up) (ensure a pressure of 5 tons at the end of pressing).

Note: The long flange of the hub is located on the 2nd gear side.

31. Install the needle bearing M, 1st gear gear N with the three-cone synchronizer rings installed on it (Fig. 5.62). Install a shaped washer with holes for pins O.



32. Fit the bearing using tool B. Vi. 1510-01, index O (Fig. 5.63).



33. Select and install a new snap ring that will fit into the groove exactly (it should fit tightly into it).

Installing the short secondary shaft gears

34. Install needle bearing A, 3rd gear gear B with three-cone synchronizer rings installed (Fig. 5.64). Using the tool B. Vi. 1510-01, index N, fit the hub of the toothed clutch C of the 3rd/4th gear. Using the tool B. Vi. 1510-01, index N, fit the sleeve D of the 4th gear pinion (ensure a pressure of 5 tons at the end of pressing).

Attention! Correctly position the notches of the three-cone synchronizer (Fig. 5.60).

35. Install the needle bearing E and gear (F) 4th gear with synchronizer ring installed. Install shaped washer G. Using tool B. Vi. 1510-01, index N, fit sleeve H of reverse gear (ensure a pressure of 5 tons at the end of pressing) (Fig. 5.65).



36. Install the needle bearing I, reverse gear J with the synchronizer ring installed (Fig. 5.66). Using tool B. Vi. 1510-01, index N, fit the hub of the reverse gear toothed clutch K.



37. Fit the bearing using tool B. Vi. 1510-01, index O (Fig. 5.67).



38. Select and install a new snap ring that will fit into the groove exactly (it should fit tightly into it).