2-5
2
6. If compression is abnormally low, inspect the
following items.
A. Starter cranks engine over.
B. Gauge is functioning properly.
C. Throttle in the full-open position.
D. Valve/tappet clearance correct.
E. Valve bent or burned.
F. Valve seat burned.
G. Piston rings worn or bent.
H. Cylinder worn or scored.
I. Head gasket blown.
NOTE: To service top-side components, see Sec-
tion 3.
7. Pour approximately 30 ml (1 fl oz) of oil into the
spark plug holes, reattach the gauge, and retest com-
pression.
8. If compression is now evident, service the piston
rings (see Section 3).
Spark Plug
A light brown insulator indicates that the plug is correct.
A white or dark insulator indicates that the engine may
need to be serviced. To maintain a hot, strong spark, keep
the plug free of carbon.
ATV-0051
Adjust the gap to 0.7-0.8 mm (0.028-0.032 in.).
ATV0052C
When installing the spark plug, be sure to tighten it
securely. A new spark plug should be tightened 1/2 turn
once the washer contacts the cylinder head. A used spark
plug should be tightened 1/8-1/4 turn once the washer
contacts the cylinder head.
Muffler/Spark Arrester
Clean the spark arrester using the following procedure.
1. Remove the cap screws securing the spark arrester
screen assembly to the muffler; then loosen and
remove the spark arrester. Account for a gasket.
PR498
PR499
2. Using a suitable brush, clean the carbon deposits
from the screen taking care not to damage the screen.
CAUTION
Before removing the spark plug, be sure to clean the
area around the spark plug. Dirt could enter engine
when removing or installing the spark plug.
! WARNING
Wait until the muffler cools to avoid burns.
Manual
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