Yamaha JT1 Series Service Manual page 38

2) Remove the valve and valve collar.
3)Remove the valve knock pin. Take care not to
damage the surfaces of the crankcase.
See Appendices for proper valve timing during in~
stallotion.
8. Checking the Rotary-valve.
1) Install the valve collar
in
the valve and check for
looseness. If 1t 1s foun·d too loose, replace it.
If
the
collar is found to have step wear due to locating
pin friction,
1t
should be replaced.
2)The 0-ring
1s
subJect to stretch. flatten mg or
hardening after a long period of use. Any stretched
or aged 0-ring may fail to snugly fit in the groove.
If it
1s
found defective,
1t
Slould be replaced with
a new one. When installing
it
grease
it.
Fig 3-13-2
Fig 3-13-3
Fig 3-13-4
Fig. 3-13-5
- 3 2 -
ENGINE
-Rotary Valve