We had a 90 KDX 200 a few years back. I inadvertently used weedeater gas in it, and it made about 10 miles before bogging down and choking to a halt. We pulled the KIPS cover off, and it was coated with old carbon and new syrupy crap from the bad premix. I got out the trusty Berryman's B-12, and sprayed it religiously. The crap washed away, the valve started moving again, we filled up with good gas and rode away. I redid the whole cleaning process again, and it ran great from then on.