help with 03 400ex smoke...

[nowukno]

Recently bought an 2003 400ex with a 440 kit in it. Quad is very strong & runs great. But it smokes (white) on startup , then eventually just full throttle. After a little more time it fully goes away...is this valve seals?

[CJM]

Valve seals would smoke on start up, then go away. Bad topend will smoke almost all the time and be grayish white. Black smoke is too rich.

[400]

sounds like its time for new piston and rings