400ex bored .080,(426)je 13/1 piston, dmc pipe, wb race cam, ported and polished,FCR carb(air box lid off and kn filter) wb rev box. Race gas motor 110 octane. now have 175 main, was running 165 but plug wasnt coloring at all! Is plug coloring even possible with four stroke on race gas? now plug is turning cardboard but almost seems to have hurt response a little and mid range. This thing is a brute! I am running a 16 tooth front and 36 rear and it is pulling it! we are doing a lot of dirt drag racing is why the gearing has to be so high. Anyone know the best tires for 2 inches of dirt or sand? now running the stock 501s which everyone claims to be the best. thanks for your help.