HER CHEE ATV-320 S Service Manual page 30

Chapter 1 Engine, Transmission & Gear
Cylinder/Piston/Crankshaft Service Information
GENERAL
。It is recommended to remove the engine from frame body for cylinder and piston service.
。If the crankshaft bearing, oil pump drive sprocket or timing sprocket need to replacement, the
crankshaft assembly must be replaced.
SPECIFICAIONS
ITEM
I.D.
Warpage
Cylinder
Taper
Out-of-round
Ring-to-groove
clearance
Piston,
Ring end gap
Piston
ring
Piston O.D.
Piston-to-cylinder clearance
Piston pin bore
Piston pin O.D.
Piston-to-piston ring clearance
Connecting rod small end I.D.
Connecting rod big end side clearance
Connecting rod big end radial clearance
Crankshaft runout
TORQUE VALUES
Cam chain adjuster base bolt
Cylinder stud bolt
Troubleshooting
Low compression or uneven compression
◦ Worn cylinder or piston rings
Excessive smoke
◦ Worn cylinder, piston or piston rings
◦ Improperly installed piston rings
◦ Damaged piston or cylinder
STANDARD mm (in)
76.000-76.010 (2.9921-2.9925)
Top
0.015-0.050 (0.0006-0.0020)
Second
0.015-0.050 (0.0006-0.0020)
Top
0.15-0.35 (0.006-0.014)
Second
0.15-0.35 (0.006-0.014)
Oil (Side rail)
0.2-0.7 (0.01-0.03)
75.985-76.000 (2.9915-2.9921)
0.010-0.040 (0.0004-0.0016)
17.002-17.008 (0.6694-0.6696)
16.994-17.000 (0.6691-0.6693)
0.002-0.014 (0.0001-0.0006)
17.016-17.034 (0.6699-0.6706)
0.05-0.4 (0.002-0.016)
0-0.008 (0-0.0004)
8 – 12 N.m (6 – 9 ft.lb)
7 – 11 N.m (5 – 8 ft.lb)
I-21
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Overheating
◦ Excessive carbon build-up on piston
◦ Blocked or restricted flow of coolant
◦ Sticking thermostat
Knocking or abnormal noise
◦ Worn piston and cylinder
◦ Excessive carbon build-up on piston head
SERVICE LIMIT mm (in)
76.10 (2.9960)
0.05 (0.002)
0.05 (0.002)
0.05 (0.002)
0.09 (0.004)
0.09 (0.004)
0.05 (0.002)
0.05 (0.002)
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75.90 (2.9882)
0.10 (0.004)
17.04 (0.671)
16.96 (0.668)
0.02 (0.001)
17.06 (0.672)
0.6 (0.02)
0.05 (0.002)
0.10 (0.004)