Thumpers, all of your help in the past has been proven accurate and comes greatly appreciated. For this, I give you my latest problem. 2001 426. Most of my MXing is at approximately 3000 ft. The bike was fouling factory specified plugs on a regular basis - one plug per one hour of riding. In graduated increments, I ran the pilot screw in 1 turn, raised the needle clip position 2 notches (1 below the top), added a hotter than factory plug and changed the main jet to the smaller of the two additional jets packaged with the new bike. Fouling is less frequent - bike runs better now - but I know things could be better. A hard day of riding still ruins a plug. I long for that 'honey brown' properly fired plug. Any suggestions or comments would be appreciated. Thanks in advance.