I posted this in the TTR forum but someone told me to post here because I would get more replies. --- My dad was riding my ttr and I was riding my xr one day but later on in the day the ttr started running bad. It runs fine if you keep it under 1/5th throttle but once you start getting the rpm's up it dies. We thought it might have been the plug so we put a new one in. Didn't help. Any suggestions on what the problem could be?