Topic: Rebuilt engine TWICE, effing thing still leaks oil.Just about done with this bik

[stueveone]

congrats!

[kghost]

I Pm'd the details on the PCV valve.

I just routed it to the stock airbox.

[coolcat2002]

I think the moral of this story is clear:  Get a Bmw R90/6.

[MRieck]

I think the moral of this story is clear:  Get a Bmw R90/6.

What....the 100 series suck?

[dramsell]

What is a gordon frame kit?

Dave R

[Sweep]

I Pm'd the details on the PCV valve.

I just routed it to the stock airbox.

For those of us that aren't using the airbox (like me with stacks) I have a harley building trick I'm planning on employing.  I'll drill the holds in the tappet covers and install a Harley shovelhead oil crossover fitting and connect a hose to that, which will be capped off by a small breather.  The only problem here is that sometimes oil can leak from the breather so if there's room I'll put the breather in a coffee can or hopefully something smaller if I can find a place to hide it all.  Every once in a while just drain the can, it's worth a shot eh?

[Wheelhorse77]

For those with the 4-1; has anyone ever tried to scavange the crank pressure by routing the breather into the collector of the 4-1 for those who have that set up?

Use the venturi to pull the vapors from the crankcase and increase hp.

[edbikerii]

Yes, I've read about that in an old auto racing exhaust design book.  In order to maximize the venturi effect, the tap would have to be welded in at the narrowest point in the exhaust, which I think would usually be the collector on 4-1s on most bikes.

I would be concerned about backfires in the exhaust pressurizing the crankcase, and possibly blowing out oil seals, etc.  Perhaps a check-valve would prevent this.

[dusterdude]

thats why you use an air pump check valve off an old chevy.

[Wheelhorse77]

That's why they invented the PCV valve for the pcv system---to stop pressure going back in for one and to prevent just what you have described above...fire in the hole...

I have seen this happen, where students have installed the pcv in the wrong direction and have blown all of the gaskets due to a backfire; not good!

In 600 hp applications, where cars have converted to exhaust driven ventilation, I have seen a quick 20-40 hp picked up depending on whose dyno and the individual application.

It would be interesting to see if anything is gained on the upper RPM band for an 836 kit.

[edbikerii]

Yes, I've heard that the increased vacuum helps the rings seal better, thus improving horsepower.

[Wheelhorse77]

Thought and proven process is that the pistons don't have to also compress air on the way down on the Intake & Power stroke. The vacuum, in a sense, aids in drawing the pistons down.