Yamaha RS90GTZ Service Manual page 169

DRIVE CHAIN HOUSING
3. Measure:
• 14 link section
Using a spring scale, pull on the drive chain
with 36 kg (80 lb) of force
Out of specification → Replace the drive
chain.
Maximum 14 link drive chain
section length:
133.35 mm (5.25 in)
Limit: 137.35 mm (5.41 in)
TIP
• Measure the length between drive chain pin
and as shown.
• Perform this measurement at two or three dif-
ferent places.
If replacement is necessary, always replace
the chain and the sprockets as a set.
4. Inspect:
• Drive chain
Stiffness → Clean and lubricate or replace.
• Drive chain plates
Damage/wear → Replace the drive chain.
Cracks → Replace the drive chain.
5. Measure:
• Brake disc thickness
Measure the brake disc thickness 1 ~ 3 mm
(0.04 ~ 0.12 in) from the edge of the brake
disc.
Out of specification → Replace.
Minimum thickness (RS90GTZ/
RS90LTGTZ):
3.5 mm (0.14 in)
Minimum thickness (RST90GTZ)
4.5 mm (0.18 in)
4-28
POWR
TR
of the drive chain
.