Periodic Maintenance Procedures
Take a side-to-side and a front-to-back measurement
shown in the figure (total 6 measurements).
The cylinder wear is uneven in different places.
10 mm (0.39 in.) [A]
25 mm (0.98 in.) [B]
60 mm (2.36 in.) [C]
Cylinder Inside Diameter
77.000 ∼ 77.012 mm (3.0315 ∼ 3.0320
in.), and less than 0.01 mm (0.0004
in.) difference between any two
77.10 mm (3.035 in.), or more than 0.05
mm (0.020 in.) difference between any
If any of the cylinder inside diameter measurements ex-
ceeds the service limit, the cylinder must be replaced with
a new one.
Since the PLATING cylinder cannot be bored or honed.
Piston/Cylinder Clearance Inspection
The piston-to-cylinder clearance is measured whenever a
piston or cylinder is replaced with a new one. The standard
piston-to-cylinder clearance must be adhered to whenever
the cylinder is replaced.
If only a piston is replaced, the clearance may exceed the
standard slightly. But it must be within the standard, in order
to avoid piston seizure.
The most accurate way to find the piston clearance is
by making separate piston and cylinder diameter measure-
ments and then computing the difference between the two
values. Measure the piston diameter as just described, and
measure the cylinder diameter at the very bottom of the
0.041 ∼ 0.068 mm (0.0016 ∼ 0.0027 in.)
Piston, Piston Ring and Piston Pin Replacement
Refer to the Cylinder and Piston section in the Engine Top
Exhaust System Inspection
The exhaust system, in particular the muffler body, is de-
signed to reduce exhaust noise and conduct the exhaust
gases away from the rider while minimizing power loss. If
carbon has built up inside the muffler body, exhaust effi-
ciency is reduced, causing engine performance to drop.
If the muffler body is badly damaged, dented, cracked or
rusted, replace it.
If the exhaust noise becomes too loud or engine perfor-
mance drops, replace the muffler baffle.
PERIODIC MAINTENANCE 2-23