my 450 done it at first, but it does not do it anymore.

 

its just the nature of the beast, the whole redness thing and glowing is only because its raw metal, not coated with any heat sheilding. while riding at Dumont at night, take a few passes up comp with the stock pipe and u can light fireworks off of it for about 10 minutes, hehe.

 

Every 4-stroke with a raw, un-painted header will glow at an idle. If you notice as you rev the motor hard the redness dims slightly(because the exhaust flowing through it is cooling the pipe a little) Your quads ARE NOT LEAN!!!!!!! My brother-in-law stripped the paint off of his 400EX headers..& sure enough..they glow red at an idle.

 

It's normal in some cases with the different pipe metals and thickness to glow red sometimes, but I always would put your EGT meter on to jet it in perfectly. Don't own an ATV without an EGT meter !