Primary Drive; Change Shaft And Change Levers; Transmission - Yamaha YT175J 1982 Service Manual

11. Checking the clutch release mechanism
Check the ball bearing fitted in the
pressure plate (1) for wear or cratches.
Primary drive
The drive gear is mounted on the crankshaft;
the driven gear is mounted on the
transmission and is integrated with the clutch
assembly.
Primary reduction ratio
No.ofteeth
Ratio
Drive Driven
25
68
2.72
1. Check the drive gear and the driven gear
for obvious signs of wear or damage
from foreign material within the primary
case.
2. If the primary drive is excessively noisy
during operation, replace both the drive
and the driven gears.
Change shaft and change levers
1. Inspect shift return spring. A broken or
worn spring will impair the return action
of the shifting mechanism.
2. Inspect change shaft assembly for ben-
ding of shaft, worn or bent splines, and
broken or worn shift arm spring. A bent
shaft will cause hard shifting.
Transmission
1. Inspect each shift fork for signs of gall-
ing on gear contact surfaces. Check for
bending. Make sure each fork slides
freely on its guide bar.
3-14
2. Roll the guide bars across a surface
plate. If any bar is bent, replace.
3. Check the shift cam grooves for signs of
wear or damage. If any profile has ex-
cessive wear and/or any damage,
replace cam.
4. Check the cam followers on each shift
fork for wear. The follower should fit
snugly into its seat in the shift fork, but
should not be overly tight. Check the
ends that ride in the grooves in the shift
cam. If they are worn or damaged,
replace.
••••••••••
5. Check shift cam dowel pins and side
plate for looseness, damage, or wear.
Repair as required, or replace.
6. Check the shift cam stopper plate,
circlip, stopper for wear.
7. Check the transmission shafts using a
centering device and dial gauge. If any
shaft is bent, replace.
8. Carefully inspect each gear. Look for
signs of obvious heat damage (blue
discoloration). Check the gear teeth for
signs of pitting, galling, or other extreme
wear. Replace as required.
9. Check to see that each gear moves free-
lyon its shaft.
10. Check to see that all washers and clips
are properly installed and undamaged.
Replace bent or loose clips and bent·
washers.
11. Check to see that each gear properly
engages its counterpart on the shaft.
Check the mating dogs for rounded
edges, cracks, or missing portions.
Replace as required.