07 Blowing oil

[Junior Boom]

My 07 is blowing oil out both its breather pipes. This is then resulting in the air box being filled up with engine oil, IT filled a good part of the bottom of the air box with about 4 hours riding. Today we changed the oil in the bike and with in Half an hour it had filled half the airbox with oil. Any advice would be appreciated as i am racing the bike this weekend and need it fixed.

[daddio]

Exactly how much oil are we talking about? If you filled your airbox half way, you lost about a quart of oil and you have some serious blow by, and need a new piston and rings.

But......... You have probably just passed the life of the breather box. Most YFZ race bikes ditch the black box and just vent the tubes to the bottom of the quad.

[WarBirdMech]

over serviced?

r u checking your oil level correctly?

[zzsa02]

My 05 did the same thing. It just started to do it one day. Cylinder was egg shape. Got the cylinder redone and new piston and rings fixed now!

[Junior Boom]

Thanks for the help guys. When we opended my motor we appeared to have the same problem zzsa02. We had the cylinder fixed, put a new piston and rings and the problem seems to be fixed.

[mxpimp2000]

mine was doing this also really bad after every moto my swingarm would be covered in oil from coming out of the air box and ruining my air filter in motor oil,

i took the black box off and ran the hose from the crank case down in front of the rear shock and the hose from the head down in front of the motor between the radiator.

i thought that would solve my problem but by just letting it go and not fixing it cost me "BIG MONEY" the rings were wore and was causing blow by which it blew the oil from my case out into the black box and air box, about 4-5 races later my motor was rattling and i took it to the shop and the piston had so much slack on the rings and it wore my cylinder coating off, i was out 250 for cylinder and another 500 for piston rings gaskets labor etc so i ended up spending 725 when i couldve changed rings for 150 and saved 600 in the long run