00' YZ250 makin weird noise

[Sankeneyii]

I was just curious if anyone could help me out with this or had any idea of what the problem is. I have a 2000 YZ250 and when i slow down and come to a stop the engine revs from high to low repeatedly for a while. Someone told me that it could be the crank seal. If anyone could verify this or just help me out with this I would appreciate it.

Thanks, Sam

[kawaboy22]

air leak somewhere?

[VAL]

Definite textbook lean condition. Could be an air leak, main seal or intake manifold or it could be a stuck float.

[AV8R]

A little lean on the pilot circuit maybe. Try screwing the air screw in a little, unless it is already out less than 1/2 turn then you will need a larger pilot jet.
check for air leaks around reed valve to case mating surfaces. Or in the boot between the carb and reed valve.