ET: Engine (Twin) Oil Leak

vibrac

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If youb fit a D cap I always found you should pop a plug in the original breather and fit a small PCV valve in the up pipe from the cap
 

Cyborg

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Personally I wouldn’t fit a D cap on the front head and block off the timed breather until I knew for sure what the front head looked like. Without removing the front exhaust rocker, you don’t know what sort of restriction is between the head and rocker bearing. It’s a bit of a convoluted path for pressure to get from the crankcase to the inspection cap to start with, so could make things worse without some minor surgery.
 

Bill Thomas

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Just fit it to the front tappet adjuster cap, With an oil separater, Job done.
 

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Bill Thomas

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You have lost me again Cy',
Who the hell is Hugh Latimer,
I have this on both my Twins for years, Some don't like the look but I have always done things different.
 

Cyborg

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He was burned at the stake for wandering off the beaten path... similar to you and your modifications. If the rivet counters do burn you at the stake... being the owner of a Vincent powered Honda, they probably use me and my blasphemous abomination as kindling.
 

Cyborg

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I was there... probably commented on the mad Englishman at you as you rode by. Although didn’t a least one leave the factory in blue?
 

oexing

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Compliments, Norman, for remembering my idea, I drilled from chain case into the gearbox filler tube, just to ventilate the primary case via the gearbox vent. It should do I hope, without filling up the gearbox with primary oil, maybe I fit sort of shield around that drilling, but I will try without this first. Certainly you´d have to get the engine breathing right before thinking about that idea of chain case venting. For this I packed a real seal between the drive side main bearings, no scroll any more. A steel ball type one way valve seems too massive to me for engine breather, better get a reed type valve - but check it for minimal contacts around the reed else it will stick a lot with any oil film in there. I did some with a feeler gauge blade and placed at the end of a hose high up like under the seat. So any minmal oil up there will drain down before exiting to free air through the breather - worked on a few bikes like this without oil mess and catch canister. The last idea was to do a phenolic paper one way valve screwed onto a valve spring cap to breathe into the oil tank (UFM ) . As said, you´d look for an engine without lots of air leaks so there is not a lot of air that has to exit via the breather, just a bit from blow-by from pistons.

Vic
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Reed/disc valve onto valve spring cap:
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hose end reed valve:
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