Glowing red exhaust pipe headers


Information and questions on GL1100 Goldwings (1980-1983)
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sambuck
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Glowing red exhaust pipe headers

Postby sambuck » Tue Sep 10, 2013 10:59 pm



Just overhauled my carbs. Bike running really good. But, as it was getting dark and I was test running my bike for five minutes, I noticed my exhaust headers were glowing red hot for about six or eight inches from the exhaust manifold back. I'd never noticed this before but I almost never ride at night. When the pipes are cool they seem normal, i.e., silver thermal paint from the pipe flange back. Anyone got an opinion? Is this normal? My pipes are Cobra straight six with one baffle in each pipe. I did have some bluing from a while back when I had a lean mix, but the newly serviced carbs are not running lean nor rich. Berdoobuck thanks you.


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WingAdmin
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Re: Glowing red exhaust pipe headers

Postby WingAdmin » Wed Sep 11, 2013 10:28 am

They should absolutely not be glowing. Two things can cause glowing headers: late ignition timing, or lean mixture. You would know if the ignition is off, as the bike will not be starting/running well - it means the ignition is happening too late in the cycle, so that the mixture is still burning when it exits the cylinder. So basically you're down to an overly lean mixture. Try enriching the mixture and see if the problem goes away.

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virgilmobile
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Re: Glowing red exhaust pipe headers

Postby virgilmobile » Wed Sep 11, 2013 11:05 am

Also,altering the exhaust will have an affect on the back pressure (scavange cycle),you may need to either increase the overall fuel mixture or increase the back pressure to compensate.
Continuing to "just run it" will most likely burn the exhaust valves.

Just my opinion.

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sambuck
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Re: Glowing red exhaust pipe headers

Postby sambuck » Wed Sep 11, 2013 12:30 pm

Thanks for the feedback, guys. You both are in the same barn dance as me. I had one person say that if my fuel contained ethanol, and the gas had sat for some time, that the fuel would separate into three layers, the bottom-most being the ethanol, and as an alcohol the ethanol burns hotter than well-mixed fuel, creating an over hot exhaust. I can put another set of baffles in the pipes (been thinking of doing that anyway since my Fat Lady makes more exhaust rumble than I like). Can anyone recommend exhaust packing? If I were to adjust the carbs for a richer mix, what should I do? Back out the adjustment screws half a turn? I have the service manual, it doesn't address the exact procedure, though, for modifying fuel mixture. Maybe fresh, ethanol-free gas and an ounce or two of Sea Foam will resolve things.
Thanks, Virgil -- appreciate the comment. You too, WingDoc BTW that 7 volt regulator I got from you works just fine after my buddy wired it -- went right in and now I can read my fuel level and engine temp again. Sambuck
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virgilmobile
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Re: Glowing red exhaust pipe headers

Postby virgilmobile » Wed Sep 11, 2013 1:49 pm

I will always continue to say....If you want it to run like the factory made it....keep it factory...
Obviously you had to change the exhaust because of rust or looks.
This is most likley the heart of your problem..
***Im guessing here***
If everything else is spot on,then the only other variable is the "new" pipes.
Rather than trying to compensate for the larger exhaust flow(louder pipes) by shoving more fuel down its throat,boosting the air flow,changing the timing,it would be indeed easier to refit your new exhaust with the necessary restrictions.

Sorry...I do have an opinion about everything...Not necessarly a good one but none the less.

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suvcw04
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Re: Glowing red exhaust pipe headers

Postby suvcw04 » Wed Sep 11, 2013 3:00 pm

If GW carbs are like most motorcycle carbs, backing the screws out only adjusts the starting circuit in the carbs.
You need bigger jets, or smaller needles to change the running mixture. The change in back pressure is letting too
much hot exhaust out too soon.
The days of putting on bigger open pipes to get more power are long gone. You MIGHT get a couple of new ponies, but the old ponies will burn to death in the heat. Go back to factory pipes, or pay someone who knows what they are doing to redo the whole system from air cleaner to exhaust tip. Mother Honda knows FAR MORE about their products than the after market guys.

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Re: Glowing red exhaust pipe headers

Postby WingAdmin » Wed Sep 11, 2013 3:35 pm

virgilmobile wrote:Also,altering the exhaust will have an affect on the back pressure (scavange cycle),you may need to either increase the overall fuel mixture or increase the back pressure to compensate.
Continuing to "just run it" will most likely burn the exhaust valves.

Just my opinion.


Right, I meant to mention that as well. Anything that is going to cause the burned/burning mixture to exit before it is meant to can cause the problem.




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