what is this thing?

[vtcl0917]

hey guys hows it goin. i was lookin at my bike today and i noticed this little thing on it. i cant seem to find out what it is, it also looks like it should have a rubber cap on it or something? while the engines running it puffs out air, haha... sorry if this is a noob question, im just curious. thanks!

 

[Flugtechnik]

It is the crankcase breather. Do not plug it.

It originally had a tube running back to the stock airbox. If you dont have that any more just put a filter on it or have a hose that runs down away from the engine.


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[vtcl0917]

alright sounds good. thanks for the advice man.

 

[AlphaDogChoppers]

DO NOT cap it! That air that it puffs out, must be allowed to puff.
It is the engine's breather, and like was said, used to go to the air box so that any gasses or oil vapor emitted from it would go into the engine and be burned. When you run an engine hard, there can be a little oil mist come out of it. Some will route the hose so that any oil coming out of it goes to the chain.

 

[crazypj]

Plug it up and watch the oil leaks start. ;D
As crankcase pressure builds up it will leak from kickstart, gearchange and output shaft and maybe even a few gaskets if you get real lucky :

Seriously though, go to local autoparts store and get a breather filter for about $10.00