1. Check:
- Piston pin
Blue discoloration/grooves → Replace the piston pin and then check the lubrication system.
2. Measure:
- Piston pin outside diameter «a». Out of specification → Replace the piston pin.
Piston pin bore outside diameter: 16.991-17.000 mm (0.6689-0.6693 in)
Limit: 16.971 mm (0.6682 in)
![](https://motoinstruction.ru/img/yamaha/3/111959.jpg)
3. Measure:
- Piston pin bore inside diameter «b». Out of specification → Replace the piston.
Piston pin bore inside diameter: 17.002-17.013 mm (0.6694-0.6698 in)
Limit: 17.043 mm (0.6710 in)
![](https://motoinstruction.ru/img/yamaha/3/111960.jpg)
4. Calculate:
- Piston-pin-to-position clearance
Out of specification → Replace the position pin and piston as a set.
Piston-pin-to-piston clearance = Piston pin bore size - Piston pin outside diameter
Piston-pin-to-piston clearance 0.002-0.022 mm (0.0001-0.009 in)
Limit: 0.072 mm (0.0028 in)