Service manual
Table Of Contents
- Inroduction
- Yamaha Motor Corporation, USA YZ/WR Motorcycle Limited Warranty
- How to use this Manual
- Index
- Contents
- Chapter 1 General Information
- Chapter 2 Specifications
- Chapter 3 Regular Inspection and Adjustments
- Chapter 4 Engine
- Seat, Fuel Tank and Side Covers
- Exhaust Pipe and Silencer
- Radiator
- Carburetor and Reed Valve
- Cylinder Head, Cylinder and Piston
- Clutch and Primary Driven Gear
- Kick Axle, Shift Shaft and Primary Drive Gear
- YPVS Govenor
- Water Pump
- CDI Magneto
- Engine Removal
- Crankcase and Crankshaft
- Transmission, Shift Cam and Shift Fork
- Chapter 5 Chassis
- Chapter 6 Electrical
- Chapter 7 Tuning
4-22
ENG
CYLINDER HEAD, CYLINDER AND PISTON
EC474402
Piston pin and small end bearing
1. Inspect:
9
Piston pin
9
Small end bearing
Signs of heat discoloration → Replace.
2. Measure:
9
Piston pin outside diameter
Use micrometer 1.
Out of limit → Replace.
3. Check:
9
Free play (when the piston pin 1 is in
place in the piston 2)
There should be no noticeable for the play.
Free play exists → Replace piston pin
and/or piston.
4. Install:
9
Small end bearing
9
Piston pin
Into the small end of connecting rod.
5. Check:
9
Free play
There should be no noticeable free play.
Free play exists → Inspect the connecting
rod for wear/Replace the pin and/or con-
necting rod as required.
Piston pin outside diameter:
Standard <Limit>
14.995~15.000 mm 14.975 mm
(0.5904~0.5906 in) (0.5896 in)
1C3-28199-10 111 04.5.17, 9:22:13 PM