Cylinder oil return hole

Lubrication System (oil feed pump and scavenger pump, reservoir, filter, and lines)
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bieb
Member
Posts: 18
Joined: Thu Sep 30, 2004 1:21 am

Cylinder oil return hole

#1

Post by bieb »

I have a 61 pan that I am currently rebuilding. Upon removal of the cylinders I notice the previous "mechanic" installed the wrong base gaskets. Both oil passages were covered. Not sure how long this was ran in this condition because I just purchased it in the fall and didn't ride it much. Now since I have the cylinders that have the oil return hole inside the cylinder, does the return hole in the base remain open?
krazyloop

Re: Cylinder oil return

#2

Post by krazyloop »

This depends on exactly which pan barrels you have. Later barrels have small holes drilled near the bottom INSIDE the piston area. The return oil thus drains down on the flywheels. Early models returned oil through the barrels into corresponding holes in the cases and don't drain the return oil onto the flywheels.

Match your new gaskets to the bottom of your barrels. See if your gaskets line up with the return holes. Then remove the gaskets and correctly position them on the cases without the barrels. See if the return holes in the gaskets line up with holes or slots in the barrel mating surfaces on your engine cases. If they do you are in business. If they don't but you have inside oil returns then you are still OK.

If you don't have flywheel draining barrels and no holes in your cases for return oil, consult the manual. It shows how and where to drill return holes in your barrels to return the oil onto the flywheels. No matter what combination you have, drilling your barrels for these holes won't cause any problems.
bieb
Member
Posts: 18
Joined: Thu Sep 30, 2004 1:21 am

Re: Cylinder oil return

#3

Post by bieb »

ok crazyloop, I thought thats the way it was. When I get the jugs back from being bored and fitted I will check. They do have the hole inside the cylinder wall so thats is where the oil should return. Just wasn't sure if the oil would return there or in the case or both.
Thanks for your help
Bieb
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