smoke pouring out

[proudy29]

hi guys i have a yz450f 2006 and it has around 75 hours on it,it had new piston and rings put in it not long before i brought it.my problem is that i went for a ride and when i turned back around i noticed heaps of smoke pouring out of the exhaust on closer inspection i noticed the oil was coming out of the over flow hoses from under the bike and it covered the back tyre and sprocket in oil.would anyone no what went wrong with the bike.thanks in advance

[grayracer513]

Sounds like damage to the rings/cylinder/piston. Have a leak down test done to verify that.

[proudy29]

so what does a leak down test involve.and thank you

[dgcars]

Have you overfilled the engine with oil......check it

[Blackwoodz]

Also check for a pinched vent hose. If the vent hose pinches off it will build crank pressure and make it push oil out.

[grayracer513]

A leak down test uses compressed air to test the sealing of the rings and valves.

Wouldn't hurt to review the oil change/fill procedure either:

https://www.thumpertalk.com/forum/showthread.php?t=852961

[proudy29]

thanks guys for all your advice.the guy that i got the bike of was very up to date with hes services and oil changes.

[grayracer513]

It's not your oil change schedule that's in question, it's the procedure. You can overfill an '06 by almost double and it won't show that on the dip stick because there's no room in the oil reservoir for the excess. If you did not drain from both drain plugs, and/or if you used more than 1 liter of oil, it's overfilled. A simple thing, worth looking into.

[yz250cranker]

i say complete rebuild one more time to make it right open it up fix it and assemble it again:thumbsup:

[dgcars]

i say complete rebuild one more time to make it right open it up fix it and assemble it again:thumbsup:

But why........

[proudy29]

hi guys i forgot to say that ive only done about 3 hours of riding on this 450 before the smoke started pouring out of the exhaust.the guy that owned it before me loved the bike that much that he sent me a text 2 weeks after i got the bike of him to let me no that it would need an oil change at a certain ammount of hours.the reasons why i got the bike was that it was a one owner bike from knew and that geoff ballard was the guy who serviced the bike when it needed to be serviced.any1 no who he was back in the day.the bike will be getting pulled down sometime this week so i will keep you guys posted