Yamaha RX10H Service Manual page 72

CARBURETOR TUNING
Low-speed tuning
The carburetors are built so that low speed tun-
ing can be done by adjusting the pilot mixture
screw 1 and throttle stop screw 2 .
CAUTION:
Never run the engine without the air intake
silencer installed. Severe engine damage
may result.
1. Tighten the pilot mixture screw until it is light-
ly seated and then back it out the specified
number of turns.
Pilot screw 1 :
Approx 2 turns out
NOTE:
Number of return rotation of pilot screw may
vary depending on each cylinder.
Make sure to rotate the screw backward after
listing its present number of return rotation on
each cylinder.
Pilot mixture screw effects:
Turn in
Leaner
Mixture
2. Set the engine idle speed by turning the
throttle stop screw 2 in (to increase engine
speed) or out (to decrease engine speed).
Engine idle speed:
1,350 ± 100 r/min
(1,250 X 1,450 r/min)
3. If low-speed performance is still poor at high-
er elevations under extreme conditions, the
standard pilot jets may need to be replaced.
In this way, the proper air/fuel mixture is ob-
tained.
NOTE:
In this case, use a larger numbered pilot jet to
enrich the air/fuel mixture.
Standard pilot jet:
#17.5
2-56
INSP
ADJ
STD setting Turn out
Richer
Mixture