Snakeoil wrote:So it is a form of positive crankcase ventilation since the head area is linked to the crankcase via the oil return galleries. It is a good idea. I wonder if it lead to premature carbon build up in the combustion chambers?
regards,
Rob
CL72 or 77
It has nothing to do with case venting as it draws clean air from the right side air cleaner up the intake valve stem (not much for sure) then when the valve opens the QUICK vacuum is supposed to suck any moisture into the combustion chamber. ........lm
Yes, you did say moisture, didn't you. So the idea was to pull the water vapor that could collect in the sump out thru the guides when the engine was up to temp. Certainly sounds like overthinking on the part of Honda to me. Guess I'll go peruse the CB77 manual to see if they provide any additional info on this. It's just a curiosity thing at this point.
Appreciate the info. Learn something new every day. That's what makes this stuff fun. regards, Rob
More likely intake air rather than case air. .......lm
Seriously guys, all they do is to allow some air to be drawn into the guide rather than have oil sucked down the guide. That's all. A simple technique rather than using stem seals.
in the end Honda deleted the breather tubes on 72/77s and on the 160/175/200 they went through the same thing and fitted a series of different seals until they got it right.
Thanks teazer.
Probably one of those MYTHS as to what HONDA did back then. BTW HONDA didn't delete them for the 72 as production had already been terminated. Ya think one could say "not all engines require seals at the valve guide"?. ............lm
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