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crankcase breather

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motobroker
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crankcase breather

Post by motobroker » Sun Jul 17, 2011 7:00 pm

Does the CL77 have any crankcase breathing outlets besides the one at the top of the engine?
It seems kind of small. Are there any mods to help with better breathing?

LOUD MOUSE
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Re: crankcase breather

Post by LOUD MOUSE » Sun Jul 17, 2011 8:12 pm

That is it and it worked for 1,000's of them. ............lm

motobroker wrote:Does the CL77 have any crankcase breathing outlets besides the one at the top of the engine?
It seems kind of small. Are there any mods to help with better breathing?

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G-Man
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Post by G-Man » Mon Jul 18, 2011 2:20 am

Motobroker

The CL77 is a 180 degree crank engine so piston pumping is cancelled out, unlike big british twins which generate a lot of pressure pulses in the crankcase (both pistons moving together). The small breather at the top of the engine is sufficient for these engines in normal use.

Earlier versions of the C72 and C77 had a breather tower at the back of the top crankcase cover which breathed out onto the final drive sprocket but this was deleted around 1962, in favor of the later arrangement even for the 360 crank engines.

G
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1960 C72 motor with breather tower
1960 C72 motor with breather tower
'60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160
'66 Matchless 350 '67 CL77
'67 S90 '77 CB400F

mrken305
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Location: Sacramento, California

Crankcase breather

Post by mrken305 » Mon Jul 18, 2011 9:18 am

There's a picture of an aftermarket racing crankcase breather in the Forum if you search for the keywords 'Whistling Wanker'. They were made by Webco back in the 60s. Since they are rare and somewhat odd looking, this info may not help you much.

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