The following change in cam case breathers is recommended
on all model 638 motors to reduce breather losses to a
- Remove oil pump and cam case cover.
- Tap out center hole between crankcase and cam case
with 1/4″ pipe tap. Plug hole with VF2285 plug.
Stake plug in. (See Fig. 2).
- Drill out and tap 7/16″ – 24 the breather hole in
cam case cover. (See Fig. 2).
- Screw in and lock tight with nut, breather inlet
- After tapping cam case cover, be sure there are no
burrs on the outside face which would prevent proper
operation of the breather disc.
- Replace cam case cover and oil pump.
- Change breather tube to 41497.
Parts required are as follows:
1 – 40718 Breather inlet nipple.
1 – 24B17 Lock nut.
1 – VF2285 Plug
1 – 41497 Breather tube.
The necessary parts to make this installation on all Indian
Sport Scouts that have been shipped to date, will be mailed
you without charge.