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Crank Case Oil Leak

Puddle jumper

Well Known and Active Forum Website User
Non-VOC Member
Hi Guys,
Hope some can help me, my HRD chop is suffering from an oil leak, that appears to be coming from the crankshaft oil seal, is a problem for because my bike runs an open belt primary and clutch, so the oil drips onto the belt and flies all over place.
The lip seal is a direct fit into the crank case (no adaptor ring) and runs on a well made spacer (concentric and the correct size) I can stop or at least slow the leak down by running with an Elephant trunk style breather, but I am still concerned that this solution is only borderline and will fail after a long run at higher speeds.
My oil pump is a new double lead pump from Vinparts which seems to work well.
The return oil goes straight back to the oil tank and the rockers are feed from the pressure side of the pump, tapped of PO39/PO40 via a restrictor jet. So I don’t think that the oil level is getting to high in crank cases. If its possible to do so?
Any thoughts!!!
DSCF9222.jpg
Picture shows the rocker oil feed

Cheers
 

Howard

Well Known and Active Forum Website User
VOC Member
Ok. Perhaps it's not passing the seal. Could it be passing through the bore of the spacer? Not very likely, but from what you describe, the seal shouldn't be the problem.

How about a non-return valve in the elephant's trunk to keep the crankcase pressure low?

H
 

Puddle jumper

Well Known and Active Forum Website User
Non-VOC Member
The spacer is sealed to the shaft with gasket glue, as for the non-return valve, I have not tried that with the elephants trunk, so it's worth a shot.
But it seems a bit extreme, as if some thing else is the problem, any idea what the oil level should be at in the engine whilst running?
 

Howard

Well Known and Active Forum Website User
VOC Member
Oil level in engine (as I understand) should be very low, the system is essentially a dry sump, the only oil in there should be in transit back to the oil tank. The return pump should pump considerably more than the feed pump (2:1 I think) so there should be virtually no oil in there. You may have run back from the tank to the sump when it's standing, I've heard of it happening, but never had that problem, I understand some people will put a valve in the oilline to stop it, but I don't like any obstructions to the flow of "life blood".

H
 

Puddle jumper

Well Known and Active Forum Website User
Non-VOC Member
Cheers Bill,
The engine has only done 600 miles on new rings and bores, not to sure how long they take to bed in?,
must admit I did wonder if that might have some thing to do with the problem.
 

Albervin

Well Known and Active Forum Website User
VOC Member
Depending on the type of pistons/rings & the initial clearances in the bore, it can take up to a thousand miles to bed everything in. My Rapide was still bedding in & getting faster after 3 thousand miles. Besides the elephant's trunk do you have another breather attached? What sort of breather did you have before the elephant's trunk? I thought elephant's trunks had a valve incorporated into them but I could be mistaken. There has been a lot of talk about 2 start oil pumps & their usefulness on street machines. Tom Gaynor has written several worthy pieces on the subject & you would be well served by searching for them in the archives. After the bike has been standing for a couple of days place a pan under it & check the amount of oil that comes out of the sump. It shouldn't be very much at all, maybe 100 ml (4 ozs) to 200ml max.
Do you have the "joggle" wires fitted to the rocker bolts? Because you are feeding oil from the pressure side the oil level in the sump may be at higher levels than normal......
 
Last edited:

Bill Thomas

Well Known and Active Forum Website User
VOC Member
Hello Paul, I think the book says 2000 mls, But they are big old pistons and Vins rev so slow it could take longer, I am in the same boat and I now live in a very slow part of U.K. Plus I have 9 to 1 pistons with race gaps, It could take Forever !! Good luck, Bill.
 
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