1. Measure:
- Valve spring free length «a»
Out of specification → Replace the valve spring.
Valve spring free length:
- Intake valve spring: 40.5 mm (1.60 in)
- Limit: 38.5 mm (1.47 in)
- Exhaust valve spring: 40.5 mm (1.60 in)
- Limit: 38.5 mm (1.47 in)
![](https://motoinstruction.ru/img/yamaha/3/111843.jpg)
2. Measure:
- Compressed valve spring force «a»
Out of specification → Replace the valve spring.
Compressed valve spring force (installed):
- Intake valve spring: 127.4-144.6 N (12.99-14.74 kg, 28.64-32.51 lb) at 32.65 mm (1.285 in)
- Exhaust valve spring: 133.0-153.0 N (13.56-15.60 kg, 29.90-34.39 lb) at 32.82 mm (1.292 in)
![](https://motoinstruction.ru/img/yamaha/3/111844.jpg)
b. Installed length
3. Measure:
- Valve spring tilt «a»
Out of specification → Replace the valve spring.
Spring tilt limit:
- Intake valve spring: 1.8 mm (0.07 in)
- Exhaust valve spring: 1.8 mm (0.07 in)
![](https://motoinstruction.ru/img/yamaha/3/111845.jpg)