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Discussion Starter #1
I have been building a Triumph chop for the last 5 months and getting to the stage that I need help.

The engine runs but spits oil out through the crank cas breather pipe located near the front sprocket.

An Ideas as to why. Where should this be piped to or just left open.

Thanks In advance.

So far
 

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I think, and it has been 45 years since i looked, butthere ought to be a very short bit of pipe to directthe oil onto teh gearbox sprocket ( to oil the chain). aslo Just check that the return oil is being returned to the tank, and you havent changed the outlet hole into the tank. either in size or height from teh original. It will affect the oiling of the top end.
 

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Discussion Starter #3
The oil is returning to the tank.

I have an aftermarket tank.

The oil to the rockers is through a regulator at the moment.

Can too much oil to the rockers cause the crank to overflow ?
 

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These are dry sump engines, so the oil flow rates are much less than is usually found on wet sump engines. Normally only a small amount of oil is directed to the top end. It is often wise when starting after a rebuild to put your finger over the return hole to boost the initial supply of oil to the top end. This oil is pumped by the scavenge side of the pump. If all of the scavenge oil was returned to the sump, it would fill as the pressure fed side feed the rod bearings then drains into the sump. So the oil fed to the top end has to be a small portion of the oil scavenged.
 

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Discussion Starter #5
I was wondering if too much oil to the top end was causing it.

How much damage can be caused by under oiling the top end?
 

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I was wondering if too much oil to the top end was causing it.

How much damage can be caused by under oiling the top end?
a valve might stick open ( bad) less likely a rocker stick ( also bad)

but now you have two parallel posts running :)

GP's suggestion is very valid. What oil are you using? it ought to be 20/50 (SG preferably )
 

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Case breather

Maybe a silly thing but it happens...
on the end of the inlet cam should be a timed disc and a spring. This opens and closes the breather through the cam to the case.
Is the spring/disc in there?
 
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