Model U valve covers

Oil seal leak

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tomo256
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Model U valve covers

#1

Post by tomo256 »

Evening Gents (well it is in the U.K.)
I took my flatty out for a run the other day and on arrival home I noticed that oil was leaking from the rear exhaust valve cover. The oil was coming out where the red pencil is pointing to in the photograph. I am hoping someone can advise me as to whether I have to remove the cylinder or not to replace the oil seal between the sliding upper and lower valve covers. Would be grateful for any advise as to the easiest way forward. I am well capable of removing the cylinder, but I am looking for the easiest route.
Thanks
Martin
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Mark44
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Re: Model U valve covers

#2

Post by Mark44 »

To the best of my knowledge and after having put together my '45 UL recently, I believe that you'll need to remove the cylinders to get at those seals.
I'm hopeful that if there's a way to do this that I don't know about, someone more knowledgeable will come in and correct me.
Little Stan
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Re: Model U valve covers

#3

Post by Little Stan »

Unscrew the cover, get some brake-clean and clean it real good. Then try something like 3M Super77 spray adhesive which might slow it down if not stop it entirely. Good news your getting oil to those guides!

-little stan
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Re: Model U valve covers

#4

Post by RUBONE »

Be sure your breather system is working well. The first place over-pressurization shows up is...there.
tomo256
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Re: Model U valve covers

#5

Post by tomo256 »

Morning Gents.
Thanks for the replies and assistance it is greatly appreciated. I have managed to get a quick look at the problem and have found that the crankcase breather on the left hand side seems to be blanked off, in saying that, it is there but does not seem to be "breathing", I am running a belt primary drive which was on the bike when I got it, the only thing that I have done is replace the "custom" aftermarket oil tank with a repo genuine style one. I started the bike up and covered the exit end of the hose attached to the crank case breather with a little saliva (yeah I know but we all do it) and there was no movement of air at all. Rubone you kindly suggested that the breather could be the issue, I am thinking that maybe the oil tank that I removed may have been vented. Could the blanking off of the crank case breather and no oil tank vent be the cause ? Or have I simply got an oil leak ?

Thanks again
Martin
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Re: Model U valve covers

#6

Post by flatboy1950 »

That little pipe on the left side supplies a drip feed of oil to the primary chain , controlled by a tapered screw in the top of the timing cover.
Usually plugged when you run a belt primary.
The scavenge pump incorporates a timed rotary breather & is part of a very sophisticated oiling system & breathing system that Indian totally ignored.
As the pistons go down the bore they cause a bit of crankcase compression , the rotary breather then opens & the oil scraped off the flywheels & air flow , pushes a lot of oil up through the mesh screen & up the hollow tube of the scav. pump , flooding the timing gears with oil & then gravitating through the mesh filter to the gear part of the scav. pump & is returned to the oil tank.
The oil supply to the crank pin is also timed so that as the pistons rise up the bore , oil is sucked through the drillings in the cam cover & t/side main shaft to feed the big end bearing. If you remove the oil pump & press a short tube into the feed hole in the cam cover & attach a yard long plastic pipe to this short tube , OIL WILL FLOW To The Pin because of the pressure difference !!!.
The side drilling of the timing side main shaft is part of the timed oil system as is the feed pump !!!
If you muck about by grooving the oil feed bush in the cam cover , you may wind up with LESS oil being fed to the crank pin !!
So , if your scavenge pump is not correctly timed , you may wind up with a permanently pressurized motor & diminished oil feed to the crank pin : In other words : A primitive Indian style set up !!!!
Flatboy.
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Re: Model U valve covers

#7

Post by RooDog »

I never imagined the breather system, and crank case vacuum, would have anything to do with feeding the crank pin. But your explanation does make perfect sense.
I do not believe this concept carries over to the later Pans,Shovels, nor Evos, however, no?
....RooDog....
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