Hey i have a trx 400 with a Big gun exaust system and it also has a Big rev box and a K&n filter. I went to glamis for halloween and when i went up competition hill i saw that where the header started turning red like on the top where it connects with the motor. Do u think i need to jet, was i forcing it to much do i need to put air whole on the air box what should i do or is it normal

this was at night? is normal about 6 inches.now if its poping or backfiring then you may have a problem.

Yea it was at night. The bike ran good better performance than before i had the exaust that was the first time i was trying out the system, i was just scared that i was messing up my bike. Thanks for the reply