Red hot

[staq50]

Started the bike up today since it hasn't run for two weeks after lockdown, just ran it on the stand till temp reached 102 C got a bit of smoke rising and looked at the down at the pipes...oops little too hot here.....didn't think they'd get that hot that quick...

 

[Sierra1]

Somebody else around here did that too. Same result, from the same action. . . . for the same reason IIRC. Apparently, she does NOT like idling in place. I'm not worried about her being parked for a while. Last time I rode her, I put some STA-BIL 360 in, and topped off the tank. The ride home mixed the treatment, and got it into the entire system.

 

[Don in Lodi]

Idle or reved?

 

[Nikolajsen]

Yes, it was me.
Also not a problem for me or my S10
(mine wont get that red, when just idling, but no high revs needed, only once in a while up to about 3-4000, you know...just "wrooom, wroom" )

 

[jeckyll]

Wow, would not have expected that. Wonder how lean it is running...

 

[WJBertrand]

I suspect this is a cold start phenomenon? Extra fuel continuing to burn in the exhaust system.

 

[Nikolajsen]

I suspect this is a cold start phenomenon? Extra fuel continuing to burn in the exhaust system.

No, I truely don't think so..
Mine would also do this, after it had been running with the fan...
It was in the winter garden, with no "moving" air, but it was winter time (not very cold, I guess around 10 celsius.

 

[jeckyll]

I suspect this is a cold start phenomenon? Extra fuel continuing to burn in the exhaust system.

Extra fuel would mean rich, and lower EGT's. This is clearly very high Exhaust Gas Temps.

Why do we have increased exhaust gas temperatures at lean mixture settings?

Answer (1 of 6): You have to remember that in an engine the mixture is within a fairly small range of equivalence ratios (oxygen to fuel) of 0.8 to 1. This chart is helpful: Peak combustion temperature is at slightly leaner than 1, around 10% excess air. This is because the excess air helps the...

www.quora.com

 

[Nikolajsen]

This is mine
(it is evening, and almost dark outside).

 

[tallpaul]

Are they stock downpipes? I wonder if a system with no cat would do the same?

 

[Sierra1]

Are the stock pipes single wall? Could that be the reason? (not that it makes the engine run different, only that with a single wall, you can see it)

 

[Nikolajsen]

Yes to stock pipe, and single wall

 

[WJBertrand]

No, I truely don't think so..
Mine would also do this, after it had been running with the fan...
It was in the winter garden, with no "moving" air, but it was winter time (not very cold, I guess around 10 celsius.

The reason I said what I said about the mixture being rich is because the only other time I saw an exhaust glowing like that (other than being run hard on a dyno) was a on a car with a misfiring engine. The misfire was allowing unburned fuel to flow into the exhaust system where it later burned. For sure the exhaust as it exited the combustion chamber was lower than normal temperature through.