bike smoking

[paper racer]

I have a 91 YZ250 with a new piston .30 over and new reeds, I also had my power valve fixed recently. After about 10-15 minutes of riding the bike starts smoking and has no power. I let it sit for awhile, started it up and it ran the same. Revved it out a bit while still smoking then rode it hard and it cleared up. This has happened both times I've been riding since I got the new piston.

 

[Studboy]

My 2 cents. Either your jetting is rich (pilot or main). Or you have a crank seal leaking letting gear oil reach the combustion chamber. Check the seal, check your gearbox oil level as well (watch to see if it changes).

 

[The Honda Pilot]

Maybe one of the seals on the head is letting radiator fluid in ? being that it was a new top end that gasket could have been messed up.

 

[paper racer]

I bought new gaskets for it. Today when I rode it and it it started to lose power I just pinned it and it ran fine once it hit the powerband and it cleared up. The pilot air screw was only turned out 1 and should be turned out 1 3/4, I will try this on Sat.

 

[IrishEKU]

Jetting.

Phillip

 

[kev_rm]

Jetting.

 

[Stew312]

Jetting