Yingang YG125-25, Maintenance Manual

Page: 51 / 144

YG125-25 Maintenance Manual Cylinder Head, Cylinder and Piston
Roundness / 0.003
Cylindricity / 0.004
Top planeness / 0.05
Piston and piston
pin
Piston external
diameter
φ
52.37
～φ
52.39mm mm
φ
52.37mm
Fit clearance with
cylinder
0.01mm
～
0.04mm 0.04mm
Piston pin external
diameter
φ
12.995mm
～φ
13mm
φ
12.995mm
Piston pin hole
inside diameter
φ
13.002mm
～φ
13.008mm
φ
13.008mm
Fit clearance 0.002mm
～
0.013mm 0.013mm
Connecting rod
small end
Internal diameter
φ
13.013mm
～φ
13.028mm
φ
13.028mm
Clearance with
piston pin
0.013mm
～
0.033mm 0.033mm
Piston ring
First ring gap
clearance
0.015mm
～
0.05mm 0.05mm
Second ring gap
clearance
0.015mm
～
0.05mm 0.05mm
First ring side
clearance
0.002mm
～
0.013mm 0.013mm
Second ring side
clearance
0.002mm
～
0.013mm 0.013mm
Oil ring side
clearance
0.002mm
～
0.013mm 0.013mm
Key torque values
Cylinder head cover connecting bolt 8-12 N.m
Cylinder bolt 40-50 N.m
Timing driven sprocket bolt 8-12 N.m
Spark plug 18-25 N.m
Pensioner plate fastening bolt 8-12 N.m
51