Yamaha WaveRunner VXR VX1800A, Service Manual

Page: 144 / 318

5-53
Valve and valve spring
• If the valve seat contact area is too narrow
and situated near the bottom edge of the
valve face, cut the bottom edge of the valve
seat using a 60° cutter to center the area,
and then set its width using a 45° cutter.
7. After refacing the valve seat to the speci-
fied contact width, apply a thin, even layer
of lapping compound onto the valve seat,
and then lap the valve using the special
service tool “1”.
Do not get the lapping compound on the
valve stem and valve guide.
8. Recheck the valve seat contact area of the
valve. See “Valve seat check” (5-50).
Cylinder head assembly
1. Install a new valve seal.
2. Install the valve “1”, valve spring seat “2”,
valve spring “3”, and valve spring retainer
“4” in this order, and then install the special
service tools “5” and “6”.
TIP:
• When installing a new valve, always replace
the valve guide with a new one.
• Install the valve spring “3” with the larger
pitch “a” toward the camshaft and the smaller
pitch “b” toward the combustion chamber.
• The upper end “c” of the valve spring “3” with
the larger pitch “a” is painted red.
a. Previous contact width
Valve lapper “1”
90890-04101
Valve lapping tool “1”
YM-A8998
60
a
1
Valve spring compressor “5”
90890-04019
Valve spring compressor “5”
YM-04019
Valve spring compressor attachment “6”
90890-04114
Compressor adapter “6”
YM-04114
1
2
6
5
4
3
a
b
c
3