Yamaha MM600D Service Manual page 49

1
CARBURETOR TUNING
Low-speed tuning
The carburetors are built so that low speed tuning
can be done by adjusting the pilot mixture screw
2 and throttle stop screw 1.
CAUTION:
Never run the engine without the air intake si-
lencer installed. Severe engine damage may re-
sult.
SEJ2790
1. Tighten the pilot mixture screw until it is
lightly seated and then back it out the speci-
fied number of turns.
Pilot mixture screw 2:
MM600: 2 turns out
MM700: 1-1/2 turns out
Pilot mixture screw effects:
Turn in
Leaner
Mixture
2. Set the engine idle speed by turning the throttle
stop screw in (to increase engine speed) or
out (to decrease engine speed).
SEJ2800
Standard idle speed:
3. If low-speed performance is still poor at higher
elevations under extreme conditions, the stan-
dard pilot jets may need to be replaced. In this
way, the proper air/fuel mixture is obtained.
NOTE:
In this case, use a larger numbered pilot jet to
enrich the air/fuel mixture.
Standard pilot jet:
MM600: #42.5
MM700: #45
2-36
INSP
ADJ
← → Turn out
STD setting
1,600 ± 100 r/min
Richer
Mixture