2003 XR-400R Why is it smoking?

I just purchased a 2003 XR-400 and it's smoking. I got it for a great price, but the oil was a bit low. The previous kept it outside and did no maintenence. The bike runs well, starts on the 3rd or 4th kick, no valve train noise whatsoever, idles great and has great power.

I'm thinking rings or valve guides, but leaning more towards rings. The air filter was dry. When I cleaned the backfire screen, there was fine dirt in the bottom of the bucket.

What do you guys think? Thanks, Steve.

Rich,

The bike smokes warm or cold. At idle or if just putting around from idle to 1/4 throttle it doesn't smoke. But it smokes if I ride it hard or blip the throttle. I may have over filled it a little, just a hair above the full mark. Should I run it towards the low side of the mark?

I just drained and changed the oil, 1.9 quarts. I will check valve clearences tomorrow too.


Thanks, Steve.