400ex red head pipes

[Schultz#508#]

i got a 400ex bored to a 407 with a stock cam the piston is 11:1 COMP ported head with no airbox UNI filter and hmf slip on. when im out riding it hard like normal the head pipes glow red for about 3 inches, i took the plug out n it was tan,could someone please tell me why its running hot and why the pipes are red.

[Scro]

It's normal for the first couple of inches to glow red, especially at night when you can see it. This is because of the walls of the pipe are thin on most pipes (stock header being the thinnest)

Now if it was glowing red, all the way back to the silencer, you would have problems. But three inches is normal.

[Schultz#508#]

alright then i wont worry bout it thanks

you rejetted it correct?

[Schultz#508#]

ya stocks a 148 i got a 165 in it now

[440exnacsracer]

a glowing headpipe is not normal, did you increase the size of the pilot jet as well? with the plug coming out tan, sounds like the main jet is probably correct, but your pilot jet is too lean, your air/fuel mixture screw is not adjusted properly, or a combination of both

[Beaudacious]

dont listen to him /\ /\ /\ glowing head pipe is perfectly normal they all do it wen they are tuned right every stock bike does it and nothing goes wrong she is making power wen the pipes are red

[440exnacsracer]

dont know what kind of tuning your doing, but its not right

[scuzz]

If it's at night it's normal.

[Beaudacious]

well let me tell you I do my own tuning with an egt guage and it is right where it needs to be i know because there is a number starring me in the face and my pipe is red from start to finish at night wen i race it

[alberto]

Ok, here is my 2 cents. When I had a stock pipe and rode hard the header never turned red. Now I have a full YOSH pipe, KN, 165 main and the header glows. I changed the plug a few weeks ago and there were little tan spots and black ashy stuff on the plug. I thought it was running rich so I took the plug to a local guy and he confirmed that I was rich. He told me to go down to a 158 main or smaller. I did and the glowing stopped. Like I said my 2 cents!!!

[Beaudacious]

that might be 2 centsbut it doesnt make any sense Red pipes are from lean running engines not rich so wen you dropped your jet size the pipe got redder

[440exnacsracer]

at NIGHT, and after REALLY hard riding, yes, a little bit of glowing is ok. and an aftermarket headpipe with perhaps thinner wall tubing may be apt to glowing a little more, but with schultz having a heavier wall stock header, in now way should it be red, and just as you said....red pipes are from lean running engines. i dont need a computer to tell me when my engines are running properly. either way, schultz, i hope you get your bike running right

[rt20ps]

With no airbox you need at least a 42 pilot. Chances are you're running lean.

[Eviltanker]

Originally posted by rt20ps
With no airbox you need at least a 42 pilot. Chances are you're running lean.

Not neccessarily true. I am running an open aluminum airbox and a 40 pilot. All is good.

[Schultz#508#]

i will put a larger jet in it and see where that gets me thanks you all 4 replying

[Schultz#508#]

when i hold it off the rev limiter theres a little bit of black smoke so it cant b runnin lean, can it?

[400exMO]

Originally posted by Schultz#508#
when i hold it off the rev limiter theres a little bit of black smoke so it cant b runnin lean, can it?
Burning oil? Bad rings or valves.

[Jessem24]

mine glows a night about 3 inches and its a bone stock motor and pipe

[Young_Gun1]

the red pipe i suppose might be from burning fuel there right after the engine

[Beaudacious]

wen you hold it on therev limiter the spark gets interupted letting unburnt fuel out the tail pipe thats why burning oil is causes blue smoke

[Schultz#508#]

the smoke is black