It has come to my attention that JS has copied my sump plug breather and now has it available on his website. My original sump plug breather is available on the NYC website.
He had posted this in an attempt to justify copying my design, and then he took it down.
I spoke to Leo at length about the breather he used on his drag racer. It was an exhaust extractor and was connected to the Combat case through the fitting on the rear . [There is no sump plug on a Combat case.] He only built one for use on his drag bike and never sold it. He also used check a check valve that went to the manifold to boost the extractor at low rpm. There were no reed valves in his breather. It was only applicable to use on a drag bike.
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What Jim Comstock is saying about my system is correct.
I did not use reed valves, I used check valves.
I was doing this in an attempt to eliminate pumping losses within the crankcase, and control oil migration into the combustion chamber while using low piston ring tensions.
I hand multiple check valves in the exhaust, and inlet manifolds.
In lower rpm, lower throttle opening conditions, where there was a degree of inlet manifold vacuum, I was using that to create vacuum in the crankcase, as exhaust velocity was not enough to create a suitable vacuum.
Under wide open throttle conditions, (no inlet manifold vacuum) the check valves closed to the inlet manifold connectors, and the exhaust manifold extraction vacuum provided the crankcase evacuation.
Closed throttle, high rpm conditions (end of track throttle roll offs) created high vacuum in the inlet manifolds, and served to help oil piston ring/cylinder sealing oil control.
I never had any plans on marketing this.
And, I can’t take any claims to being the originator of this.
It’s been used on various engines for a while.
Moroso sells a exhaust extraction kit for auto engines, which is very similar to what I was doing, less the inlet manifold circuit.
Many engines used a timed breather for pressure/vacuum control as well. (Norton, HD, Triumph and several others have cam driven/timed breathers)
The Comstock reed valve breathers work very well, and I use them on all of the engines I build.
I use the ones he sells through CMW, which attach to the crankcase, and the ones he designed for sump plug use, sold through Kenny At NYC Norton.
I personally lay no claim to originating this particular design/idea of crankcase evacuation.
I just expanded it somewhat with putting the inlet manifold vacuum into the circuit.
What I was doing, in my opinion, would not be very suitable for a street bike.
Comstock’s two systems are, however, highly advantageous for street, or racing engines.
Haven’t seen or tried the JS Engineering sump plug ones, but in the pictures I’ve seen, they appear to mimic the ones Jim Comstock designed, engineered, and produced.
It has come to my attention that JS has copied my sump plug breather and now has it available on his website. My original sump plug breather is available on the NYC website.
He had posted this in an attempt to justify copying my design, and then he took it down.
I spoke to Leo at length about the breather he used on his drag racer. It was an exhaust extractor and was connected to the Combat case through the fitting on the rear . [There is no sump plug on a Combat case.] He only built one for use on his drag bike and never sold it. He also used check a check valve that went to the manifold to boost the extractor at low rpm. There were no reed valves in his breather. It was only applicable to use on a drag bike.
View attachment 94455