4 wheeler exhaust red hot

bobs330 · 03-04-2011, 04:55 PM

why does being lean cause that much heat???

SlammedRanger · 03-04-2011, 05:00 PM

I don't suspect he is reving it or the choke is causing it. Ky brother starts his up and holds the throttle to keep it idling. As do I because 400s are cold blooded and a pain to keep running when its cold. I would say your lean on the pilot. Step up to a 42 and it will start easier and won't make the header glow red. I have to hold throttle to mine the same way to keep it running until it warms up. Not reving the &%$# out of it just steady throttle till it warms up then it will idle. Get a 42 its a god send for winter or cold starts.

Redracer · 03-04-2011, 05:09 PM

Quote:

Originally Posted by bobs330

why does being lean cause that much heat???

The air/fuel ratio has too much air and not enough fuel. The fuel is what cools the cylinder down. The result of too much fuel is a wet/saturated spark plug, aka fouled plug.

bobs330 · 03-04-2011, 06:31 PM

duh, that makes sense.

Redracer · 03-04-2011, 06:40 PM

Quote:

Originally Posted by bobs330

duh, that makes sense.

No reason for the Duh... I learned the same way you are. Kudos for asking

my5sons · 03-04-2011, 07:39 PM

I'm not arguing with you guys about it, so don't take this the wrong way. I am certainly not saying that I am right, but with cars (ok don't kill me, but I did compare this to a car), I have had the experience of having too much fuel dump into the engine and the headers will glow red because it continues to burn inside the hot exhaust gas. Also, I have seen this with plugged up catalytic converters. Obviously, there are no cats on these things, but is it possible that it sat long enough that there is a nest or something packed inside the spark arrestor?

and timing too! But with an 08, probably not likely! Thanks for everyone's patience. I'm still learning here!

Helmut · 03-04-2011, 07:43 PM

Quote:

Originally Posted by my5sons

I'm not arguing with you guys about it, so don't take this the wrong way. I am certainly not saying that I am right, but with cars (ok don't kill me, but I did compare this to a car), I have had the experience of having too much fuel dump into the engine and the headers will glow red because it continues to burn inside the hot exhaust gas. Also, I have seen this with plugged up catalytic converters. Obviously, there are no cats on these things, but is it possible that it sat long enough that there is a nest or something packed inside the spark arrestor?

and timing too! But with an 08, probably not likely! Thanks for everyone's patience. I'm still learning here!

I've seen automobiles do this too.

my5sons · 03-04-2011, 07:47 PM

good! So I'm not imagining, so now I just have to get this air cooled thing with the lean condition down. I understand it makes the engine hot, but still trying to figure out how it makes the headers glow red!

My thoughts are too much fuel is dumping in, spark doesn't burn it all, excess fuel ends up in the header, exhaust gases are extremely hot, and the gas ignites the unburnt fuel and gets fanned by the exhaust gas. Am I that far off on my theory here?

and, let me add another theory, that it's possible the exhaust is partially plugged not releasing all the gas, which makes it worse? No?

Helmut · 03-04-2011, 08:00 PM

Quote:

Originally Posted by my5sons

good! So I'm not imagining, so now I just have to get this air cooled thing with the lean condition down. I understand it makes the engine hot, but still trying to figure out how it makes the headers glow red!

My thoughts are too much fuel is dumping in, spark doesn't burn it all, excess fuel ends up in the header, exhaust gases are extremely hot, and the gas ignites the unburnt fuel and gets fanned by the exhaust gas. Am I that far off on my theory here?

On an ATV, running lean does make the pipe glow, but I don't know if getting too much fuel would cause it to do that or not. The automobiles that I've seen do that have been fuel injected and the pressurized fuel kept going into the exhaust.

I don't really know why a lean engine heats the pipe up that hot, unless it's because the pipe is so thin. Could also be the extra hot exhaust gasses coming out of the head and hitting air (oxygen) in the pipe, causing an effect similar to the way acetylene torches get hotter when oxygen is introduced into the flame. Just a guess.

General_Lee · 03-17-2011, 11:26 PM

if i hold mine off idle about 1/4 to half it will glow in about 3 to 5 min let it bakc down will clear right up of get going and it will stop glowing and yes i know this is a old thread but thought i would add to it incase somone was looking for a answer to there problem