2003 yz450f smoke

my yz450f is putting out only alittle bit of blue smoke, but when its warm it stops, it only does this when its cold. Other than that there is none. and its not running funny or anything, just like any other 450 motor wise, just blue smoke when its cold, help me out here guys, cause i REALLY hope i dont have to rebuild it.

my yz450f is putting out only alittle bit of blue smoke, but when its warm it stops, it only does this when its cold. Other than that there is none. and its not running funny or anything, just like any other 450 motor wise, just blue smoke when its cold, help me out here guys, cause i REALLY hope i dont have to rebuild it.

Blue smoke mean oil burning. Could be valve guides, but most likely rings. When was your last re-build?

When you warm up your bike, just let it idle. Don't blip the throttle until it's warm.

Wringing out the throttle when it's cold will just cause pre-mature wear.

not sure, i just bought the bike about a month ago. so still figuring things out about it.

A single puff or very brief exhaust of oil smoke on a cold start (sitting for 30 minutes or longer, roughly) is usually an indication of leaking valve guide seals. Oil drools down the stems while it sits, and then burns off on start up, after which it looks pretty normal. VG seals can also cause a single puff of smoke when you come back on the throttle after deceleration. Ring usually lead to smoke under a load.

Oil smoke has a smell that is noticeably different from coolant steam, and steam vanishes into the air, while smoke has to drift away and dissipate.

yes, it is ONLY when its cold, but when its warm, not any type of smoke at all. i got my brother to follow me yesterday on it and he said there is nothing at all cause its warm and hot by that point.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now