Installing The Valves And Valve Springs - Yamaha MX250 Service Manual

VALVE
5
a
2.
Clean off all of the lapping compound from the valve
face and valve seat. Apply fine lapping compound on
the valve face and lap the valve as described in step
1.
3.
Once the contacting surface of the valve face is pol-
ished and becomes shiny, apply mechanic's blue lay-
out fluid to make sure that there are traces of even
contact in the center of the valve face.
NOTICE
Do not let the lapping compound enter the gap
between the valve stem and the valve guide.
TIP
After every lapping procedure, clean off the compound
from the valve face and valve seat.

INSTALLING THE VALVES AND VALVE SPRINGS

The following procedure applies to all of the valves, valve
springs and related components.
1.
Install:
• Valve stem seal
4
• Valve "1"
3
• Valve spring "2"
2
• Valve spring retainer "3"
M
• Valve cotter "4"
1
Use the valve spring compressor "5" to install the
E
parts.
Valve spring compressor:
NOTICE
• Do not compress the spring more than necessary.
• Surface "a" with the rounded edges of the valve cot-
ter must face downward (to the valve spring retainer
side) when installing it on top of the valve spring
b
retainer. If surface "b" of the opposite side is facing
downward when the valve cotter is installed, it could
result in the premature wear of the valve cotter.
3-31
(Intake side only)
New
New
90890-01253
1
2
3
4
5
6
7
8
9
10