Author Topic: crankcase breather  (Read 2804 times)

Offline trevinoz

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Re: crankcase breather
« Reply #15 on: 16.04. 2014 22:10 »
Strange that it didn't work, Brian. That is exactly how the breather system works on the Norton twin engine.


Online Brian

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Re: crankcase breather
« Reply #16 on: 16.04. 2014 23:39 »
I did a similar thing to a plunger and it did seem to work ok. On the plunger I put a metal tube up through the bottom of the oil tank so it went almost to the top of the tank and then connected the breather to that.

On the s/arm model I put the fitting in the top of the oil tank but it didnt work. Could be the s/arm model had a lot further and higher to push the oil compared to the plunger.

The s/arm one breathed into the tank ok but it must have increased the crankcase pressure enough to start oil leaks.

It was never a big problem but occasionaly if I pulled up on someones nice clean driveway it would drop one or two drops of oil from the breather and I wanted to try and stop that.

Online muskrat

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Re: crankcase breather
« Reply #17 on: 17.04. 2014 07:55 »
I use a Bunn breather on the cafe. The motor breaths in yia the rocker box and out via the crank case hole to the oil tank then to atmosphere. A one way valve if fitted at each end. No gasses stay in the motor and it revs quicker. I have disabled the timed breather by cutting it off at the holes so gas can escape at any time.
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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