450F 03 YZF 450 Air Flow Through Camshaft Breather Pipe ???

M

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
 
SRAD97750

SRAD97750

Moderator
Staff member
mla2k4mla2k4:
... 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??
Click to expand...
Quite normal. Even if it blows a bit of oil.
It's a breather hose. The pressures from the piston rising up and down in the engine need to be evacuated or the cases would burst, blowing the gaskets out of the flanges.
Which happens on my WR in about 2 minutes if the transmission breather hose plugs with sand. The right hand clutch cover gasket blows out.
-BIG DAN:thumb:
 
snowflake

snowflake

its blow by, all engines have it to some extent, on a car this is managed by a pcv valve, on your bike its just straight flow.

If you believe it to be excessive, a fresh set of rings and valve seals wouldn't hurt.
 
cleonard

cleonard

There are two components. Every time the piston goes up it sucks 450cc of air and then blows it back out on the down stroke.

Blowby is the second component and it biases the flow to more out than in.
 
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