Cleaning
Thoroughly clean the gearbox parts before inspecting. Use a brush or scraper to remove all deposits and clean the holes and slots of possible contamination, then flush to remove and dissolve all oil residues.
Blow the parts with compressed air and gently wipe them. Blow out the bearings with particular care, directing the jet of compressed air in such a way that no rapid rotation of the rings occurs.
Crankcase and covers
There should be no cracks on the crankcase, and no wear or damage on the surface of the bearing bores.
The mating surfaces of the clutch housing, back cover and bottom cover must not be damaged to prevent oil leakage. Smooth out minor damage with a file. If the parts are too damaged or worn, replace them with new ones.
Check the condition of the front cover and make sure that the input shaft does not touch it when rotating. If shaft and cover misalignment is found, replace damaged parts. Check if the oil drain hole in the cap is clogged (shown by an arrow on rice. 3-15). Clean the drain plug.
Oil seals
Check the seals for damage, excessive wear and uneven sealing lips. Wear of the working edges of the glands in width is allowed no more than 1 mm. If even a slight defect is found, replace the seals with new ones.
Shafts
On the working surfaces and on the splines of the output shaft, damage and excessive wear are not allowed. The rolling surfaces of the needles at the front end of the shaft must be free of roughness and burrs.
Check the condition of the rolling surface of the needles in the input shaft bore.
Inspect the intermediate shaft, which is not allowed to chip or excessive wear of the teeth.
The surface of the reverse gear shaft must be perfectly smooth, without any signs of binding. The size of the mounting gap between the axle and the bushing of the intermediate reverse gear is 0.056-0.09 mm, the maximum allowable gap is 0.15 mm. Check the clearance by measuring the diameter of the axle and the hole of the gear bushing. For new parts, the axle diameter is 19.079-19.094 mm, and the inner diameter of the pressed bushing is 20.05-20.07 mm.
Eliminate minor irregularities on the surfaces with fine emery cloth. In case of large damages and deformations, replace the shaft with a new one.
Gears
The gears must not show any damage or excessive wear on the teeth. Pay special attention to the condition of the ends of the teeth on the synchronizer rims.
The contact patch of the gear teeth should be located over the entire surface, which should be smooth and without signs of wear. Check the meshing clearance between the gear teeth, the mounting value of which should be 0.10 mm; wear limit - clearance -0.20 mm.
The mounting gap between the bushings and gears of I and V gears and between the secondary shaft and gears of II and III gears should be 0.05-0.10 mm; limit wear-gap - 0.15 mm.
If the wear exceeds the allowable limits, replace the gears with new ones.
Bearings
Ball or roller bearings must be in perfect condition. Their radial clearance should not exceed 0.05 mm.
Pressing the inner ring against the outer ring with your fingers, turn one of them in both directions, while rolling should be smooth. The surface of the balls or rollers and the raceways of the rings must not be damaged. Replace damaged bearings with new ones. When replacing the front bearing of the input shaft, use the ejector A.40006 (rice. 2-11); while the flywheel can not be removed.
Rods and forks
Deformation of the shift forks is not allowed. The rods should slide freely without significant play in the crankcase bores.
Check up a condition of blocking crackers of rods, springs and balls of clamps. Parts that show signs of seizing or wear must be replaced with new ones.
Hubs, couplings and synchronizer rings
Check the clutch hubs for signs of seizing, especially on their sliding surfaces. Pay special attention to the condition of the ends of the coupling teeth.
Excessive wear of the surface of the blocking rings is not allowed. They must be replaced if they butt against the synchronizer sleeve. Remove possible irregularities that prevent free sliding with a velvet file. Parts that are worn out more than acceptable limits, replace with new ones.