Yamaha WR450F, Owner'S Service Manual

Page: 396 / 794

4 - 38
ENG
VALVES AND VALVE SPRINGS
REMOVAL POINTS
Valve lifter and valve cotter
1. Remove:
• Valve lifters
1
• Pads
2
NOTE:
Identify each lifter
1
and pad
2
position very
carefully so that they can be reinstalled in their
original place.
2. Check:
• Valve sealing
Leakage at the valve seat
→
Inspect the
valve face, valve seat and valve seat
width.
Checking steps:
• Pour a clean solvent
1
into the intake and
exhaust ports.
• Check that the valve seals properly.
There should be no leakage at the valve
seat
2
.
3. Remove:
• Valve cotters
NOTE:
Attach a valve spring compressor
1
between
the valve spring retainer and the cylinder head
to remove the valve cotters.
Valve spring compressor:
YM-4019/90890-04019