Why?

[Lucky]

anyone have any theorys as to why the scavenger hoses (the ones that go from the airbox to the valve covers) are such radicly different sizes? ?has anyone noticed what a big difference there is between the two fittings?

the only thing i could think of is that one cylinder (the rear)might have a certain amount of blowby built in because it would get less cooler air and thus more expantion...??

just a thought, and either i have too much time on my hands, (not likley) or there really is something to this that should be considered when doing a rebuild...

by the way, i once kinked the hose to the rear cylinder when i threw the airbox on quick for a test ride after doing some work, and got a nasty surprise 30 feet out of the driveway when one of the half round plugs in the valve cover gasket blew out and oil sprayed EVERYWHERE.  i just poped it back in wiped off the oil and straightened out the hose, all was well, but something i will not forget again!

--Lucky

[ArrrGeee]

well, first of all I've never noticed that there was a difference
in sizes. Just a thought, it's probably for some type of scavenger effect. Where regular engines these day's have
a PCV valve and a breather to scavenge and recycle blowby gases, if you apply a certain amount of vacuum to to ports
of different sizes you would probably get a one directional
flow. I'm no engineer but the official way to test a PCV system
according to the good folks at General Motors ( many moons ago) was to put a piece of paper over the breather side of
the valve cover and see if it would stay held in place by vacuum.
 
So, having 2 different sized openings on the valve cover seems logical to me.

ymmv

-Ron