Checking The Timing Chain; Checking The Crankshaft Sprocket; Checking The Timing Chain Guide; Installing The Plunger Seal - Yamaha 2009 YFM25RY Service Manual

4. Check:
• Crankshaft sprocket
Damage/wear → Replace the crankshaft.
• Bearing
Cracks/damage/wear → Replace the
crankshaft.
5. Check:
• Crankshaft journal
Scratches/wear → Replace the crank-
shaft.
• Crankshaft journal oil passage
Obstruction → Blow out with compressed
air.
EAS4D3F022

CHECKING THE TIMING CHAIN

1. Check:
• Timing chain
Damage/stiffness → Replace the timing
chain and camshaft sprocket and crank-
shaft sprocket as a set.
EAS4D3F023

CHECKING THE CRANKSHAFT SPROCKET

1. Check:
• Crankshaft sprocket
More than 1/4 tooth wear "a" → Replace
the timing chain and camshaft sprocket
and crankshaft sprocket as a set.
CRANKSHAFT ASSEMBLY
a. 1/4 tooth
b. Correct
1. Timing chain roller
2. Crankshaft sprocket
EAS4D3F024

CHECKING THE TIMING CHAIN GUIDE

1. Check:
• Timing chain guide (intake side)
Damage/wear → Replace the timing
chain guide (intake side)
EAS4D3F025

INSTALLING THE PLUNGER SEAL

1. Install:
• Compression spring "1"
• Plunger seal "2"
• Dowel pin "3"
Check the plunger seal smooth operation
pushing the plunger seal by your finger.
EAS26210
INSTALLING THE CRANKSHAFT ASSEM-
BLY
1. Install:
• Crankshaft assembly "1"
• Balancer weight
5-59