hey i got a pretty much stock 400ex... i got nerfs and new tires... i want some more power... is venting the airbox lid worth the time.. and do i need to rejet if i vent it?

 

Another question... Last night i fouled a plug out... ( i was quick revving the motor... got a new plug and it started right up... i was sittin in my drive way at about 1/8 throttle recharging the battery... i noticed my head pipe was glowing bright orange... is this bad or.... normal? it went back to normal when i let off the gas for about 10 seconds)

 

you should NEVER let an air cooled quad idle for an exended period of time, theres no air blowing through tha fins which means NO COOLING, so no cooling equals MORE HEAT which means hot metal (exhaust) which turns red when hot

 

you could try to turn the fuel skrew out 1/2 turn or so to make your bike idle at a richer setting. this won't make it as hot, but you still never want to let your bike idle for more than a minute or two after being warmed up.