Yamaha YZ125 2009, Owner'S Service Manual

Page: 33 / 234

2-3
MAINTENANCE SPECIFICATIONS
MAINTENANCE SPECIFICATIONS
ENGINE
Item Standard Limit
Cylinder head:
Combustion chamber capacity 8.4 cm
3
(0.296 Imp oz, 0.284 US oz) ----
Warp limit ---- 0.03 mm
(0.0012 in)
Cylinder:
Bore size 54.000–54.014 mm (2.1260–2.1265 in) 54.1 mm
(2.130 in)
Taper limit ---- 0.05 mm
(0.0020 in)
Out of round limit ---- 0.01 mm
(0.0004 in)
Piston:
Piston size/ 53.957–53.972 mm (2.1243–2.1249 in) ----
Measuring point "H" 17.5 mm (0.69 in) ----
Piston clearance 0.040–0.045 mmm (0.0016–0.0018 in) 0.1 mm
(0.004 in)
Piston offset 0.5 mm (0.019 in)/EX-side ----
Piston pin:
Piston pin outside diameter 14.995–15.000 mm (0.5904–0.5906 in) 14.975 mm
(0.5896 in)
Piston ring:
Sectional sketch Plain ----
B=1.0 mm (0.039 in) ----
T=2.35 mm (0.093 in) ----
End gap (installed) 0.5–0.7 mm (0.020–0.028 in) 1.2 mm
(0.047 in)
Side clearance (installed) 0.035–0.070 mm (0.0014~0.0028 in) 0.1 mm
(0.004 in)