Need to know...
0. Stock engine, or using a sled engine?
1. What plug are you running (and fouling) -- NGK BR8ES or BR9ES (Autolite 4063 & 4062, resp)? What Hoodlum said...what does the business-end of the plug look like?
2. Location (climate & altitude)
3. Stock carb? What main jet you running? What is your air screw at (# of turns out)?
4. Mods on your engine, or stock? Tuned pipe? Port work? Water-cooled? Etc?
5. What fuel/oil mix? Fuel octane? What oil?
6. Have you ever done an air-leak test? Compression test? Plug-chop?
7. Made any recent changes or adds to your setup?
8. It just start fouling plugs recently, or is this a new-to-you buggy? New to two-strokes?
(I feel like the BMV person right now, ha)
Most likely your carb / fuel setup.
-Dan
