Yamaha 2006 RX10GTAXW Service Manual page 827

Spark plug color
Light tan or gray
Dry black or fluffy
deposits
White or light gray
White or gray
insulator with small
black or grayish
brown spots and
electrodes having a
bluish-burnt
appearance
Melted electrodes
and possibly a
blistered insulator
Metallic deposits on
insulator
Troubleshooting
Trouble
Hard starting
Poor idling:
S Poor performance
at low speeds
S Poor acceleration
P l ti
S Slow res onse to S Slow response to
throttle
S Engine tends to
stall stall
CARBURETOR TUNING
Main jet selection chart
Diagnosis
Carburetors are tuned
properly.
Mixture is too rich.
Mixture is too lean.
Mixture is too lean.
The piston is damaged or
seized.
Mixture is too lean.
The spark plug melted.
Diagnosis
Insufficient fuel
Excessive use of the
starter or choke
Fuel passage is clogged or
frozen
Overflow
Improper idling speed
adjustment
Damaged pilot screw
Clogged bypass hole
Clogged or loose pilot jet
Air leaking into the
carburetor joint
Defective starter valve seat
Overflow
2-57
Remedy
Replace the main jet with the next smaller
size.
Replace the main jet with the next larger
size.
Replace the piston and spark plug.
Tune the carburetors again. Begin with low-
speed tuning.
Check the piston for holes or seizure.
Check the cooling system, gasoline octane
rating and ignition timing. After replacing
the spark plug with a colder type, tune the
carburetors again. Begin with low-speed
tuning.
Adjustment
Add gasoline.
Return the starter lever to its seated posi-
tion so that the starter valve is fully closed.
S Check and, if necessary, clean the fuel
tank air vent, the fuel filter and all of the
fuel passages.
S Check and, if necessary, clean the
carburetor air vents, fuel passages and the
float valve.
S Clean the float chamber of any ice or water.
Adjust the fuel level.
Adjust the engine idle speed.
Refer to "Low speed tuning".
Replace the pilot screw.
Clean the bypass hole.
S Remove the pilot jet, clean it with
compressed air and then install it.
S Make sure that the pilot jet is fully tightened.
Retighten the clamp screws on the
carburetor joints.
Clean or replace the starter valve seat.
Adjust the fuel level.
INSP
ADJ