Adjusting The Engine Idling Speed - Yamaha RAPTOR 90 2020 Owner's Manual

who has the necessary professional knowledge
and experience. The adjustment described in the
following section, however, may be performed by
the owner as part of routine maintenance.
ECB00481
NOTICE
The carburetor has been set and extensively
tested at the Yamaha factory. Changing these
settings without sufficient technical knowl-
edge may result in poor performance of or
damage to the engine.
EBU24002

Adjusting the engine idling speed

The engine idling speed must be checked and, if
necessary, adjusted as follows at the intervals
specified in the periodic maintenance chart.
TIP
A diagnostic tachometer is needed to make this
adjustment.
1. Start the engine and warm it up.
TIP
The engine is warm when it quickly responds to
the throttle.
2. Attach the tachometer to the spark plug lead.
3. Check the engine idling speed and, if neces-
sary, adjust it to specification by turning the
throttle stop screw at the carburetor. To in-
crease the engine idling speed, turn the throt-
tle stop screw in direction (a), and to decrease
it, turn the screw in direction (b).
1. Throttle stop screw
Engine idling speed:
1600–1800 r/min
9-20
(a)
(b)
1
9