I am fiddling with an 03 wr450f with stock pipe and 48pilot jet with plastic intake insert removed from directly under seat. I have been trying all sorts of pilot jets and turns on the screw. The bike just keeps stuttering. I read the threads about removing the TPS and blocking off the ACV. Anyways, I got frustrated with not being able to get rid of that annoying stutter and then unplugged the TPS. What a difference. My questions are these. First, is the TPS bad or did yamaha screw up bad? Second, when running these things wot on the straight trails in the upper penninsula am I risking engine damage due to altered timing? Is the default map better than the TPS can provide? These things are a pain in the butt. The flywheel already sheared the key as well so I lapped the flywheel back in and tightened the nut to 47ft/lbs as the dealer suggested. Help?