Oil pump

[cwilli]

I want to replace check ball and spring in oil pump on 48 Chief. Any tips on removing distributor and putting
it back in the same position? Or any tips on ball and spring?

[tfburke3]

Mark the lower clamp to pump body with a pencil and loosen lower clamp and remove whole assembly,put back same.
The check ball relieves any back pressure thru the pinion .What is the issue?
The ball valve to prevent wet sumping from sitting is in my opinion more problematic and I leave it out.
I would rather deal with some wet sumping than have the motor starved for oil because the ball valve ,for
whatever reason,doesn't open.
Lots of anecdotes of how they work and factory service shots recommending removal.
Tom

[tomfiii]

Do not leave ball out, check seat closely for damage. Balls were only left out on NYPD bikes due to problems in winter.

[tfburke3]

The ball valve does nothing when the bike is running except to reduce suction pressure,flow, equal to the spring pressure required to open.
. NYPD bikes were no different than than any other 48-53,but did have a large motor pool to document issues.
If I had confidence of a repro spring being exact pressure etc,(which I don't),I would still leave it out.
Tom

[DEEBS47Chief1991]

I have read that it is common to leave the ball out for safety. I would give Mike Tomas from Kiwi a call and run the question by him. He rebuilds these pumps all the time. This is from his web site. Clear as a bell.


oil pump.jpg

[cwilli]

The issue is wet sumping after a couple weeks without running. As far as the exploded view, it looks to me like there is two balls and springs. Number 8 and 9 are still there.

[Skirted]

For many years I've been running without the ball identified in red box shown in illustration Deebs posted above.
You can replace ball and spring but chances are the fragile aluminum seat for ball 8 may need attention. Different schools of thought on method used. Its easy to make it worse if not careful and calculated. I am of philosophy that you want a thin narrow seat which increases the force of ball onto a smaller area.
My 48 never sumped in 11 years but just started a little after 2-3 weeks at end of last year. Visually the seat looked OK. I replaced ball and spring and just very "lightly" gave the ball a "love" tap while on seat to correct any minor non-conformity. So far so good but it has not sat more than 3 weeks so far this season.

[DEEBS47Chief1991]

They all drip down a little. When my 47 Chief sits for a while I open the high level NPT sump screw and drain off any excess before starting. It's easy and safe for the motor and takes 5 minutes. I have been doing this for 33 years. However, I have seen guys put a shut-off petcock on the pump feed line. Very dangerous for the forgetful.

P.S. #8&9 are still being used in the diagram. #18 was to be removed.

[Skirted]

However, I have seen guys put a shut-off petcock on the pump feed line. Very dangerous for the forgetful.

Antique guys expected to perform 100% memory efficiency by remembering to turn on the blood flow before starting. I can't even remember to turn the gas on with a crowd of spectators.

[PaulCDF]

Mike Tomas has a Tech Video on "Oil Pump Timing" at Kiwi Indian.