WD- 40 will work ok according to Brush Research. 10% less is the best. The top of the cylinder is critical,l desire to keep the pressure constant at that point. Run it in and out at a slow rate bathing in WD-40. Be sure to run out the top and back in while rotating. EG recommends Aluminum Oxide but Silicon Oxide at 320 grit works good also, a little cheaper. Travers has them on sell this month. I clean with Simple Green. If you don't have Gordon Jennings book- Two Stroke Tuning, get it will make you a better motor person. Available via Ebay every once and awhile.
JC