- Piston ring side clearance
Out of specification → Replace the piston and piston rings as a set.
Before measuring the piston ring side clearance, eliminate any carbon deposits from the piston ring grooves and piston rings.
Piston ring side clearance:
- Top ring 0.030-0.065 mm (0.0012-0.0026 in).
- Limit 0.115 mm (0.0045 in)
- 2nd ring 0.020-0.055 mm (0.0008-0.0022 in).
- Limit 0.115 mm (0.0045 in).
![](https://motoinstruction.ru/img/yamaha/20/126754.jpg)
2. Install:
- Piston ring (into the cylinder)
Level the piston ring into the cylinder with the piston crown.
![](https://motoinstruction.ru/img/yamaha/20/126755.jpg)
a. 10 mm (0.4 in)
3. Measure:
- Piston ring end gap
Out of specification → Replace the piston ring.
The oil ring expander spacer's end gap cannot be measured. If the oil ring rail's gap is excessive, replace all three piston rings.
Piston ring end gap:
- Top ring 0.15-0.25 mm (0.0059-0.0098 in).
- Limit 0.50 mm (0.0197 in).
- 2nd ring 0.30-0.45 mm (0.0118-0.0177 in).
- Limit 0.80 mm (0.0315 in).
- Oil ring 0.10-0.40 mm (0.0039-0.0157 in).