Yamaha YBR125 Custom, Service Manual, Page: 97 / 218

ENG
Check and repair
3.Measure:
Inner diameter of piston pin hole b
Exceeding limitation → Replacement
2.Measure:
Push the piston ring a into cylinder(at point 5mm to top
Inner diameter of piston pin hole:
15.002 15.013 mm
Using limitation:
15.043 mm
Piston ring
1. Measure:
Side clearance
Exceeding specified value range → Replacing the whole
set of piston and piston ring.
Note:
Before measuring side clearance,get rid of carbon
deposit in piston ring groove and each ring.
Side clearance:
1 ring:0.03 0.07 mm
Using limitation:0.12 mm
2 ring:0.02 0.06 mm
Using limitation:0.12 mm
Note:
Eject and push piston ring with piston to make the
ring vertical to cylinder surrounding.
4 - 28