Before cleaning the throttle bodies, check the following items:
- Valve clearance
- Spark plugs
- Air filter element
- Throttle body joints
- Fuel hoses
- Air induction system
- Exhaust system
- Breather hoses
Warning:
- If the throttle bodies are subjected to strong shocks or dropped during cleaning, replace them as a set.
- Before removing the throttle bodies to clean them, check the operation of the throttle bodies, refer to "Fuel injection system".
1. Check:
- Throttle bodies. Cracks/damage → Replace the throttle bodies as a set.
If the protector "a" is scratched or damaged, replace the throttle bodies as a set.
![](https://motoinstruction.ru/img/yamaha/20/126867.jpg)
2. Clean:
- Throttle bodies
Notice:
- Observe the following precautions; otherwise, the throttle bodies may not operate properly.
- Do not open the throttle valves quickly.
- Do not subject the throttle bodies to excessive force.
- Wash the throttle bodies in a petroleumbased solvent.
- Do not use any caustic carburetor cleaning solution.
- Do not apply cleaning solvent directly to any plastic parts, sensors, or seals.
- Do not directly push the throttle valves to open them.
- Do not touch the bypass air screw "a" with a white paint mark; otherwise, the throttle body synchronization will be affected.
![](https://motoinstruction.ru/img/yamaha/20/126868.jpg)
a. Place the throttle bodies on a flat surface with the air filter case side facing up.
b. Install the caps (895-14169-00) onto the hose fittings "a".
![](https://motoinstruction.ru/img/yamaha/20/126869.jpg)
c. Push the lever in the direction shown in the illustration to hold the throttle valves in the open position.
Warning: When cleaning the throttle bodies, be careful not to injure yourself on the throttle valves or other components of the throttle bodies.
Notice: Do not open the throttle valves by supplying electrical power to the throttle bodies.
![](https://motoinstruction.ru/img/yamaha/20/126870.jpg)
d. Apply a petroleum-based solvent to the throttle valves and the inside of the throttle bodies to remove any carbon deposits.
- Do not allow any petroleum-based solvent to enter the opening for the injectors.
- Do not apply any petroleum-based solvent to the portions of the throttle valve shafts between the throttle bodies.
e. Remove the carbon deposits from the inside of each throttle body in a downward direction, from the air filter case side of the throttle body to the engine side.
Notice:
- Do not use a tool, such as a wire brush, to remove the carbon deposits; otherwise, the inside of the throttle bodies may be damaged.
- Do not allow carbon deposits or other foreign materials to enter any of the passages in each throttle body or in the space between the throttle valve shaft and the throttle body.
f. After removing the carbon deposits, clean the inside of the throttle bodies with a petroleum-based solvent, and then dry the throttle bodies using compressed air.
g. Make sure that there are no carbon deposits or other foreign materials in any of the passages "a" in each throttle body or in the space "b" between the throttle valve shaft and the throttle body.
![](https://motoinstruction.ru/img/yamaha/20/126871.jpg)
3. Adjust:
- Throttle bodies synchronizing. Out of specification → Replace the throttle bodies.
Refer to "Synchronizing the throttle bodies".