No oil leaks..

Hmm, ok so a reed valve seeems the best way to go. The Dorman item doesn't seem to be available in the UK, although it looks like similar things are. I'll have to do some research, thanks for the pointers!

i just installed the cnw breather on my 72 today
going to ride tommorow then check for leaks. previous owner did the timing case mod but was still leaking allover. put the hose from that onto new breather and blocked off the timing side .hope it solves the leaks.combat engine.

COMNOZ (Jim Comstock) still makes and sells his sump plug reed valve. I put it on my '74 Commando and instantly all oil leaks stopped. Additionally it quickly forces any oil in the crankcase (due to wet sumping) back to the oil tank.

There are a lot of reed valve options and I've tried several including the two below. On the left is a reed from a Chinese scooter that was recommended to me years ago. The right is from the BMW boxer twin. They work equally well but the adapted two stroke reed uses more screws, more gaskets and is bulky compared to the neat little BMW version that was designed for twin motorcycles from the beginning.





Another I tried from Mike. Not sure where it originated. It worked well but some on this forum have said that it can get gooey/sticky when cold because its not directly connected to the motor and doesn't get enough heat.

wow that chinese scooter valve looks just like the cnw one. i just installed the real one. whats up with that

the other one is the yamaha xs 650 reed valve i believe

i still have the leak on the front fins after the cnw breather install, must be from the5/16 studs ,no leaks elswhere. timing side was done by previous owner, old britt mod he said,whats next?

jseng1 said:

Another I tried from Mike. Not sure where it originated. It worked well but some on this forum have said that it can get gooey/sticky when cold because its not directly connected to the motor and doesn't get enough heat.

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That reed valve looks similar to the one I've ordered from Holland Norton Works, which sits at the top of the line, right by the oil tank – if it gets gooey I'll share, but HNW specify a much longer breather hose than standard, for my bike anyway, routed under and up behind the battery. Whether that keeps anything liquid from getting as far as the valve, we'll see ...!

thegip said:

wow that chinese scooter valve looks just like the cnw one. i just installed the real one. whats up with that

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You'll have to ask Matt at cnw about which parts and machine work come from China.

Yes - one of the breathers shown above is a Mikes XS breather. Its changed over the years.

To fix your oil leak at the head gasket - use the sealer and wire method described here (use the sealer on all 4 surfaces):
http://jsmotorsport.com/technical_compression.asp

thanks for that info, i took my wrenches out and snugged up everything up top. no more leak at the fins. musta been the inlet rocker cover wasnt tight at all, only 130 miles on rebuild that previous owner had done.