Board index Flathead Power-Technical Questions, Answers, and Suggestions Big Twin Flatties UL valve covers

UL valve covers

Post Sat Nov 12, 2005 3:08 pm
don User avatar

Posts: 575
Location: Spokane WA USA
Here is some archived talk on tappets. ... pet+blocks


Post Sun Nov 13, 2005 2:49 am

Posts: 630
Location: belgium
I'm a little shocked about the silence on this subject.
It's a 1950's factory mod to WL's and G's and continues in the K models I think.
It greatly improves lubrication to the tappets by oil forced thru the holes by the flywheel centrifugal force and it helps again with the breathing off the crankcase as excess pressure gets away.
No worry when your gaskets are o.k. as there is no excess oil cause there is a moment off suction(fluttervalve!)when the pistons go up.
I do this to all 4cam Harley's and it helps quieting them down and last longer and hey it's a cheap and easy progress.

Post Sun Nov 13, 2005 3:48 am

Posts: 369
Location: Bergen, Norway
When doing this mod. do you also install some kind of stem to guide seal?
Do you have experience with the valves getting to much oil with this modification (assuming the clearance is within spec.) or won’t this be a problem?

Last edited by GuS on Sun Nov 13, 2005 1:12 pm, edited 1 time in total.

Post Sun Nov 13, 2005 6:36 am

Posts: 54
Location: Portland, oregon. USA
Hey Thanks Steph:
Your apparently right on the K model lifter guides being drilled...The NOS set I have are done at the factory..
Anyway appreciate the input....


Post Mon Nov 14, 2005 3:47 am

Posts: 630
Location: belgium
Never had an overoiling problem with this mod, usually all these bikes have very little lube on those parts(the tappets) and it's them that take a lot off the friction and sliding between cams and valves...but it's true when using NOS guides(army stock)in "45's the valves are very loose in my opinion, so I use aftermarket undersized guides and ream till wanted specs.That way they last a little longer and are quiet, the oil helps there also.

Post Wed Nov 16, 2005 7:02 pm

Posts: 919
Location: RENO,NV. U.S.A.
I own a set of '47 WL cases that had the oil holes drilled,this happened at least as early as '47. BREWSKI


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