Note: Prior to synchronizing the carburetors, the valve clearance and the engine idling speed should be properly adjusted and the ignition timing should be checked.
1. Stand the motorcycle on a level surface.
Note: Place the motorcycle on a suitable stand.
![](https://motoinstruction.ru/img/yamaha/16/122173.jpg)
2. Remove:
- rider's seat
- fuel tank. Refer to "Fuel tank and seats".
3. Remove: air duct (1)
![](https://motoinstruction.ru/img/yamaha/16/122174.jpg)
4. Remove: vacuum plugs (1)
5. Install:
- vacuum gauge (1)
- engine tachometer (2) (to the spark plug lead of cyl. #2)
![](https://motoinstruction.ru/img/yamaha/16/122175.jpg)
- Vacuum gauge: 90890-03094
- Engine tachometer: 90890-03113
6. Start the engine and let it warm up for several minutes.
7. Check: engine idling speed
Out of specification → Adjust. Refer to "Adjusting the engine idling speed".
- Engine idling speed: 950-1050 r/min
8. Adjust: Carburetor synchronization
a. Synchronize carburetor #1 to carburetor #2 by turning the synchronizing screw (1) in either direction until both gauges read the same.
b. Rev the engine two or three times, each time for less than a second, and check the synchronization again.
![](https://motoinstruction.ru/img/yamaha/16/122176.jpg)
- Vacuum pressure at idle speed: 34.7-37.3 kPa (260-280 mmHg)
Note: The difference between the two carburetors should not exceed 1.33 kPa (10 mmHg).
9. Check: engine idling speed
Out of specification → Adjust.
10. Stop the engine and remove the measuring equipment.
11. Adjust: throttle cable free play. Refer to "Adjusting the throttle cable free play".
Throttle cable free play (at the flange of the throttle grip): 4-6 mm
12. Install:
- vacuum plugs
- air duct
- fuel tank
- seat