Service manual

TRBL
SHTG
Troubleshooting
9-11
69J1D11
Symptom: The engine idle speed is not steady, but increases or decreases.
• Check the intake manifold.
• Check the air intake system.
• Check the ignition system.
Out of
specification?
Are the throt-
tle valves
synchronize?
Check the second-
ary air intake on the
O-ring and manifold
plate, idle speed
control hose, and
the gaskets of the
vacuum check bolts.
Check the ignition timing.
Yes
Yes
No
No
Check the operation of the
throttle cable and throttle link.
Yes
No
Adjust the throttle cable and
throttle link.
Good operat-
ing condition?
Check the synchronization of
the throttle valve.
Check the engine using the
Yamaha Diagnostic System.
Synchronize the throttle valves.