Lost Thread on Crankcase Pressure

[WZ507]

Might somebody with either better recall than me and/or superior searching skills help me locate some information on the forum that I can longer find. More specifically, I am seeking information on crankcase pressure with a variety of one-way breather valves. The specific thread I am seeking involved a Comnoz Commando engine fit with a crankcase MAP sensor, the MAP sensor output was fed to an oscilloscope, and the crankshaft was fit with an angular encoder. With the motorcycle running on a dyno at a variety of speeds, this test rig allowed the capture of oscilloscope images showing the actual pressures in the crankcase as a function of crankshaft angle. Comnoz had posted several oscilloscope screen captures at different engine speeds and with different one-way crankcase breather valves. So, this is the information I was hoping to review and reacquaint myself with. Thanks in advance for any assistance you might be able to offer.

 

[L.A.B.]

This?

crankcase reed breather

Here is why I use a reed breather directly to the crankcase. Here is a picture of a fitting I stuck on my bike, The hose runs to a water manometer. Here is a video of a full throttle pull. You can see the crankcase maintains vacuum right up to just before the rev limiter kicks in at 7500...

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[WZ507]

LAB, thank you for your contribution, and that is all interesting, even more so if the links were still alive, but no this is not the thread I had in mind. But I'm sure this is the experiment that led to the results I am after. The one I'm seeking was a more refined undertaking where the engine set-up had an electronic MAP sensor on the crankcase, in turn tied to an oscilloscope and also included an angular encoder for crankshaft angle. Comnoz posted several screen captures from the oscilloscope that showed the pressure as a function of crankshaft angle.

 

[Time Warp]

A google (picture) search showed this thread below that you posted in with a Photobucket image of a oscilloscope pic but it is not in the thread itself so perhaps lost.
If the thread / link is not gone entirely, maybe it can be found with that storage 'thing that holds gone things (Like Vintage Brake when it vanished for a bit.
I forget what it is called and a long shot (besides contacting JC)

Product release - new style one way case breather

I’ve been interested in one way breathers ever since the 1980s when Leo Goff used them on his world championship dragster. I tried them but was never happy with the fit until now. This new one way breather fits inside the timing cover so you don’t have to drill holes in the exterior of your...

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[gortnipper]

Might somebody with either better recall than me and/or superior searching skills help me locate some information on the forum that I can longer find. More specifically, I am seeking information on crankcase pressure with a variety of one-way breather valves. The specific thread I am seeking involved a Comnoz Commando engine fit with a crankcase MAP sensor, the MAP sensor output was fed to an oscilloscope, and the crankshaft was fit with an angular encoder. With the motorcycle running on a dyno at a variety of speeds, this test rig allowed the capture of oscilloscope images showing the actual pressures in the crankcase as a function of crankshaft angle. Comnoz had posted several oscilloscope screen captures at different engine speeds and with different one-way crankcase breather valves. So, this is the information I was hoping to review and reacquaint myself with. Thanks in advance for any assistance you might be able to offer.

Here you go.

Head Gasket Leak Near Left Exh

I bought mine new. The dealer was supposed to do it at the first service at 500 miles. Then it started leaking after getting some miles (5000) on it and it was time to replace the head gasket. Last time, I retorqued mine at 5, 50, 100, 250, 500, 1000 and 2000 miles. A little nutty maybe. :)...

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[Time Warp]

Legend.
I saw 'head gasket leak near left exhaust' in one of my google picture search link addresses (the one with the oscilloscope pic) and dismissed it but now see the thread topic diverged (a surprise)