I've started blowing smoke on decel. After some advice from others, I chacked the breather and it seems clear. Last weekend I replaced the plugs (very wet and black). After only a 5 min. ride, the new plugs look the same.

Where should I start? And the big question....how much is it going to cost me?

 

On decel it is usually a carburetor problem.
Float too high or needle too high or too big of an main jet.
You need to review and let us know what is your carb basics set at.

 

If its a thumper it could be bad valve stem seals.

 

It looks and smells like oil smoke as opposed to rich mix smoke.

 

So its a 2 stroke?

 

???? No. it's the 650.

I was having problems with the jetting and it smoked until I backed the air screw out. By mix, I mean air/fuel mix.

 

I'm not sure but wouldnt backing out the screw richen the mixture seeing as how the screw if after the carb? if it was on the other side of the carb (intake side) backing out the screw would lean the mixture out, maybe I have dont know what I am talking about, just my .02, how many turns you have the screw from the lightly seated position? mine is like 3 turns out and runs awesome