YZF 450 Air Flow Through Camshaft Breather Pipe ?

Hi everyone, 

 

Im going abit mad, I was at my local track on Saturday and for the first time ever I noticed that there was a considerable flow of air out of the breather pipe coming from the camshaft cover (about as hard as you could blow through the pipe if you tried only continuous)

 

so my question is, is this normal?? I've never noticed anything like this before.

 

My mind is torn between the optimistic dont worry the camshafts are spinning that must be the cause....

 

and terrible thoughts of cracked heads and leaking valves (seals?)

 

 

 

other notable points:

 

the air is not smokey, or particularly warm or hot

 

another breather is present that goes to the frame - this is also pressurised the same

 

 

 

Can anyone with a similar bike check this for me??

or anyone with similar experiences?

 

Thanks in advance for the help I dont have anyone i can ask locally

 

edit: The bike is a 2003 yzf 450 - No mods

Edited by mla2k4mla2k4
Hi everyone, 

 

Im going abit mad, I was at my local track on Saturday and for the first time ever I noticed that there was a considerable flow of air out of the breather pipe coming from the camshaft cover (about as hard as you could blow through the pipe if you tried only continuous)

 

so my question is, is this normal?? I've never noticed anything like this before.

 

My mind is torn between the optimistic dont worry the camshafts are spinning that must be the cause....

 

and terrible thoughts of cracked heads and leaking valves (seals?)

 

 

 

other notable points:

 

the air is not smokey, or particularly warm or hot

 

another breather is present that goes to the frame - this is also pressurised the same

 

 

 

Can anyone with a similar bike check this for me??

or anyone with similar experiences?

 

Thanks in advance for the help I dont have anyone i can ask locally

 

edit: The bike is a 2003 yzf 450 - No mods

If you can wait till 7 ill let you know!

it's called the crankcase breather.  It normalizes pressure when the piston moves up and down (changing volume inside the crankcase just like it does in the cylinder).  A lot of people route this into the airbox so it stays clean, preferably on the filtered side.

 

and YES, that much air movement is normal.

Edited by bikedude987

It's normal you've just never noticed it before.

Ya it's normal Like bikedude987 stated it's for relieving crankcase pressure when the piston goes up/down

if theres alot it could be whats called BLOWBY

which is an indication you need new rings.

Thanks for the reply's guys, after looking some more i could find one thread that said 'all is fine' as well. So now I can relax a little :)

 

I'm happy with that because I've had plenty of trouble with it already so paranoia is setting in.

 

 

 

 

What I don't understand with all the answers is the reasoning why though?:

 

I'm obviously missing something, but how is the camshaft cavity connected to the crankcase cavity? there are no breather pipes linking the two so how can piston movement/blow by be the cause of air movement up there?

Ah what a moron....... where the camchain runs

 

wish I thought of that last weekend.

 

 

Thanks again.

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