1901-1953 Indian Motorcycle – Parts – Accessories – Service

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Vertical Oil Pump Modification

By Pete Sink

The oil pump needs to be sealed at two locations. The first location is the
center partition between feed and return. The hole where the drive shaft
passes through needs an “O” ring or seal. My machinist cut a ring groove
and fitted an 013 “O” ring. You can also fit a seal here. The second location
is the hole in the pump cover where the Drive Gear fits inside the oil pump
outer cover. My machinist fit an 015 “O” ring. You can also fit a seal here.
With these two locations sealed the pump can now be assembled to the
timing case cover. You are now ready to test the work. Assemble a hose
and funnel to the feed oil tube. This is the tube closest to the bottom. I
attach the cover in Soft Jaws in my vise. Fill the funnel with oil and when the
oil gravity feeds to the pump, turn the pump over by hand until oil shows at
the pinion seal. Let it sit overnight and check the timing case sump pick up
hole for oil. This is the hole that mates to the crankcase to return oil from the
sump. Then check the drive gear to cover for oil appearing. If you do not
find oil at either location you have successfully sealed the pump. All of the
above is shown in the pictures provided.
Please see the photos of the “o” ring application to the oil pump. After you
assemble the oil pump to the timing cover, attach the hose and funnel. Fill
funnel with oil. Turn the pump over by hand until you get oil to the pinion
seal. Let stand in the soft jaws of vise over night. If it is sealed there will be
no oil at the sump pickup hole on the timing cover as well as no oil dripping
from the drive gear through the pump cover.
I think that any machine shop could modify the oil pump for the
installation of two (2) “O” rings. Jim Preussner at Southwest Vintage Cycle
can do it. I purchased Vitron 013 and 015 “O” rings for my job. I can supply
the “O” rings.
There are actually 2 modifications done to the pump.
One is for sealing up the inside wall of the pump, the other is sealing upthe
shaft hole in the pump cover. He has a Harley seal that he uses inside the
pump instead of an o ring. He feels that it seals better. Also the ends of the
check valves will need to be cleaned up and re-seated. New springs might
be needed on the check valves as well.

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