4-stroke smoke

[yz280f]

When I started my bike yesterday it smoking like a 2-stroke. Once it warmed up it was gone, and was fine for the rest of the day. The guys I was with were as confused as I was, so Im looking for some help in diagnosing this issue. Thanks

[Dancryzf]

What colour smoke? Blue? White? How are your levels? coolant, oil?

[yz280f]

all levels are good and just changed oil and coolant. Smoke was white

[BC3]

Not for sure, but it sounds like it sumped up and had a FULL crankcase and when it pumped the oil back into the frame it stopped smoking.....Might be a bad check valve in the oil pump feed line?

[BC3]

How long did it sit between the time you ran it last and the SMOKE happening?

[yz280f]

it had only been a few days since it had last run

[BC3]

Might want to check the oil level before starting it for a few days and see how low it goes between rides.....My TT 500 used to do that for the longest time and I changed the check valve and it stopped it......Not sure how the new Yamaha's are set up but there must be a check valve somewhere.....All it takes is a hair across the ball and it will seep into the motor....

[yz280f]

thanks I'll look into that

[Dancryzf]

White smoke usually indicates water being burnt, and a lot of the time a headgasket failure, might be worth keeping an eye on your coolant and see if it drops at all?

[BC3]

You can smell coolant when it gets in the exhaust...Kinda sweet smell