Operation Manual

6-15
PERIODIC MAINTENANCE AND MINOR REPAIR
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EC000082
cC
88
Make sure the air filter is prop-
erly seated in the air filter
case.
88
The engine should never be
run without the air filter
installed. Excessive piston
and/or cylinder wear may
result.
EW000131
w
Make sure that the fuel hoses and
vacuum hose are properly con-
nected, in place and not pinched. If
a hose is damaged, be sure to
replace it.
EAU00629
Carburetor adjustment
The carburetor is a vital part of the
engine and requires very sophisticat-
ed adjustment. Most adjustments
should be left to a Yamaha dealer
who has the professional knowledge
and experience to do so. However,
the following may be serviced by the
owner as part of routine mainte-
nance.
EC000094
cC
The carburetor was set at the
Yamaha factory after many tests. If
the settings are changed, poor
engine performance and damage
may result.
b
a
1
EAU00632
Idle speed adjustment
1. Start the engine and warm it up
for a few minutes at approxi-
mately 1,000 to 2,000 r/min.
Occasionally rev the engine to
4,000 to 5,000 r/min. The engine
is warm when it quickly responds
to the throttle.
2. Set the idle to the specified
engine speed by adjusting the
throttle stop screw. Turn the
screw in direction a to increase
engine speed and in direction b
to decrease engine speed.
1. Throttle stop screw
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