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Question about oil through the crank vent on a 72 Triumph?

1K views 7 replies 4 participants last post by  tgb3040 
#1 ·
Hello,
I just bought a 72 Triumph Bonneville 650 engine. It has an open crank ventilation; open into the transmission that is. I am not used to this since I only wrenched 69 and earlier before. I mounted a new alternator stator. I wanted to make sure everything was alright so I ran the engine without the transmission cover for about 5 minutes. During this, almost a pint of engine oil came through and out on the ground. This seems a little excessive to me, but I don’t know what to expect. Do I need to tear the motor apart in search of a fault, or might this be considered normal?

Best
 
#4 ·
It's normal. There's no seal on the crank on the later models, there are also a few small breather/oil return holes (I believe).

The primary and engine share the same oil.
 
#7 ·
Yes, I am starting to think: oil pump.
Now I can't get the motor started to check the return flow. I have a spark and I have fuel, so this indicates to me oil in the crank case.
I have good oil pressure, but the non return valve in the return piston might be leaking... That would give me these symptoms.
Hmmm, now, of to work.
 
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