400ex smokes out of Breather on valve cover

[afa913]

anyone knowwhati need to look at if my 400ex is smoking out of the breather on the valve cover.  I just put a new top end in and it runs great other than that. Too much oil?   Is the breather suppose to have a hose on it? Mine doesnt

Edited December 22, 2018 by afa913

[Frank Angerano]

Did you check the oil level ? 

[skidooer_3]

If you put new rigs in and if you broke one you may be getting blow by causing too much crank case pressure. Most valve covers with a tune in it should have a hose on it and probably feeds back to the breather box. Check out parts schematics on line and see if there is a hose. If it does then you'll need it.

[afa913]

ok, thanks guys. I havent checked the oil yet because i had been riding it and wasnt sure if it would be accurate. The manual says to let it idle without throttle for 10 minutes before checking
 

[Dnawilli2]

Blow by time for top overhaul

[afa913]

Hope it doesnt need a top overhual since thats what i just did.   I did more research and there is a tube that comes off the valve cover and goes into the top of the oil tank.  I explained it as smoke but i guess a better way to describe it would be steam

[afa913]

Well, i found the breather tube that i tucked away up in the front of the plastic when i did the top end, i guess i just forgot about it,  Hooked it up and ran great with no smoke. Oil level was perfect and oil was nice and clean.  Also after the break in process had to adjust the valves again. They were loud as hell after about an hour of run time. Seems like everything is working as it should now..... Thanks everyone for the tips

[Frank Angerano]

Simple fix! 

Safe riding brother!