I think I've been having the same problems with my engine running rich. All the plugs, especially the rear ones, we're covered in soot, I get what I believe is a cough through my air filter and I can't tell you an exact number but I think my fuel consumption is awful.
I'm not as mechanically inclined as most of the participants in this thread but I would like to try and fix this myself. After reading all the messages, I have a lot of questions!!!
How do I know what carb I have??
Is the accelerator adjuster screw accessible without removing major components?
How do you know how far out the PMS is?
Thanks everyone! Hopefully I can fix this myself, with the price of gas here in Toronto, Ontario, Canada, I need all the help I can get!!!! Today's price, $1.30 a liter.... That's almost $5/gal
Most likely, you're bike has the stock carb, you can tell by looking on top of it. If there's a black plastic dome, it's stock.
You'll need to remove the air cleaner to get to the accelerator pump screw.
Only way to know how far out the PMS is, is to tighten the screw until it's barely snug, and count the number of turns as you go.
Best thing to do is check the tech section of this site under carburetors and read up all you can. Lots of good info there.