Oil leak out of breather tube!

I have a 2009 yz450, fresh rebuilt about 10 hours ago. Did some hard riding last night and laid it down pretty good and sat there for about a minute while running. Went home after and Parked it, all was running fine just like normal. When I parked it like 4 drops of oil came out of breather tube, is this normal or should I be worried. It's never done this before.

I had the exact same experience verbatim with my 16 yz450f this weekend. I don't think it's a big deal.

Entirely normal

It's normal.....usually due to being over filled with oil. Both the yz250f and yz450f seem to be sensitive in regards to the correct oil level.Over fill them even alittle and they leak. Our 2016 yz450f doesn't leak to much but or 2016 yz250f does it all the time...our 2014 yz250f leaked too.

You don't need to overfill to get this behavior, although that will exaggerate it.  All that's required is to ride it hard. 

Thanks guys! Appreciate it! Thought Maybe blew a piston ring or something.

You don't need to overfill to get this behavior, although that will exaggerate it. All that's required is to ride it hard.

You're probably right but I will say this...on my kids 250f if I keep the oil level right in the middle of the sight glass we don't get too much dripping out the breather compared to if its at the top of the sight glass. On my 450f I hardly ever get any drops coming out the breather tube but then I'm old, slow, and don't ride to hard anymore!!!

Edited by Edge316

Oil is slingin everywhere in the case when u ride a little bit will come out sooner or later

I have a 426 2001 that blowing oil out the pcv valve. I'll ride 20-30 min. and I'll be down 1/2 a quart. It there anything under the valve cover that needs to be looked at? And does the engine have to be pulled to get the valve cover off to take a look? This bike is new to me. I know it's not burning oil. Any Ideas Fellow Thumper Riders?

I have a 426 2001 that blowing oil out the pcv valve. I'll ride 20-30 min. and I'll be down 1/2 a quart. It there anything under the valve cover that needs to be looked at? And does the engine have to be pulled to get the valve cover off to take a look? This bike is new to me. I know it's not burning oil. Any Ideas Fellow Thumper Riders?

Head or base gasket could be blown, as far as taking the engine off i try to do as little as possible you should be able to get in there without removing the engine

Overfilling is the most common cause of this.  Be sure you check the oil level only after the bike has been run for at least a minute, and within 5 minutes of shut down.  The breather is a simple 12mm hose, no valve of any kind, and very little baffling.  Nothing to really inspect. 

 

You can completely disassemble the entire top end in the bike. 

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