[sueshamen]

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Hi everyone, I was refered to this site my my local HOC.

We have an 81 GL1100 which we are hoping to get on the road as soon as possible but it has a problem with the exhaust.

Within 15-20 seconds of firing up one exhaust glows bright red and is very very hot.

The exhaust sysem is brand new so is the fuel.....any help would be greatly appreciated.

 

[corneo]

imported post

Need a little more inf. on where it's glowing red.
Inside the pipe, the tail pipe itself, the bend at the exhaust connection?
New exhaust, is it chrome, painted black?

I really doubt it is the fuel.... unless you are using some special type of fuel.

 

[sueshamen]

imported post

Brand new stainless steel exhaust (genuine honda ones)
Engine recently been rebuilt, big ends, pistons, general internal workings.
Exhaust glowing at port end of number 4 cylinder
Fuel just ordinary unleaded

 

[FitzAl]

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The Honda exhaust isn't stainless but normal steel. Motad do make a stainless set (or at least they did once apon a time). Are the carbs set up correctly? Too lean a mixture will lead to hot pipes (normal blueing), you will need to examine the spark plug from that cylinder and compare it to the others to get a clue.

BTW, what's your "local HOC" mean?

 

[sueshamen]

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Have checked the plugs and all are set up ok.

HOC means Honda Owners Club

 

[Jason]

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Glowing exhausts has to be either waaaay too weak a mixture or possibly valve timing off. If the valve timing is off you would notice it in the performance and it would also affect the other cylinder on the same side. I'd be inclined to look at the mixture adjustment again.

 

[Guest]

imported post

FitzAl wrote:

BTW, what's your "local HOC" mean?



I thought it might of meant "harley owners club" :gunhead:Hey Sueshamen, welcome to the forum. :clapper:These guys will soon sort out your problem. :waving:

:santawaving: :18red: :santawaving:

 

[Eamonn1200]

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Whats the possibility of one of the pipes being thinner than the others and getting hot quiicker?

 

[corneo]

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I had a 750 that had a really hot pipe and the heat was at the engine. (where the pipesconnect) What was the problem was # 2 cylinder wasn't firing and putting extra work on the # 1 and # 3 cylinders. (inline 4 cylinder)

The reason it wasn't firing was a carb problem, # 2 wasn't getting any gas. I fixed the carbs and the problem went away.

I would say, check the temperature of the other pipes. (however you want to do it.) and see if # 3 is colder than the other pipes.
Make sure # 3 is working. (I don't mean has a spark) You said the engine was rebuilt, I don't know how much was rebuilt but it sounds like a cylinder isn't working. The problem could be from the carbs to the rods, values, a piece of garbage somewhere.

I've seena engine that was rebuilt and the wrong size rods were put in and the values never closed. Needless to say it had no fire.

So taking baby steps first, let check temperatures and go from there.

 

[Shooter]

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I want to say to take a close look at the exhaust valve for that cylinder. Sure sounds like you're getting combustion through a partialy opened valve. Ran into the same problem on a small block Chevy, after a head swap. Timing doesn't have to be off very far to let an exhaust valve open a few thousandths early.

Also, a belated welcome to the BEST GOLDWING forum going...

 

[exavid]

imported post

I'd also take a good look at the intake side of things, a vacuum leak on the hot cylinder can easily bring up the temperature due to a leaning out of the mixture. It's a common problem on high performance 2 strokes getting Exhaust Gas Temps matched on all the cylinders and operating below maximum allowable temps. You might want to be careful until you figure this one out, it's also not uncommon to pull a plug on a hot cylinder and find aluminum from the piston sintered onto the plug. It's almost always a mixture problem. You can tell the temperature of an exhaust pipe by the color it glows per below.





Colourings

[align=center]Celsius[/align]

[align=center]Fahrenheit[/align]


[align=center]Lowest visible red[/align]

[align=center]475° C[/align]

[align=center]525° F[/align]


[align=center]Lowest visible red to dark red[/align]

[align=center]475-650° C[/align]

[align=center]525-1202° F[/align]


[align=center]Dark red to cherry red[/align]

[align=center]650-750° C[/align]

[align=center]1202-1382° F[/align]


[align=center]Cherry red to bright cherry red[/align]

[align=center]750-800° C[/align]

[align=center]1382-1472° F[/align]


[align=center]Bright cherry red to orange[/align]

[align=center]800-900° C[/align]

[align=center]1472-1652° F[/align]


[align=center]Orange to yellow[/align]

[align=center]900-1100° C[/align]

[align=center]1652-2012° F[/align]


[align=center]Yellow to light yellow[/align]

[align=center]1100-1300° C[/align]

[align=center]2012-2372° F[/align]


[align=center]Light yellow to white[/align]

[align=center]1300-1550° C[/align]

[align=center]2372-2822° F [/align]













As you can see, once the pipe begins to glow at all it's getting dangerously hot. To allow it very long can burn a hole through the piston top, especially if the engine is under any load. Check this out and cure it before riding.

 

[exavid]

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Sorry about the stretched out table, it looked okay before I sent it:gunhead:

 

[englishted]

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A leak at the manifold is a good point Paul. I would have thought you might have a missing cylinder though if you had a leak. I suppose if its a slight leak the cylinder will still fire anyway.

 

[sueshamen]

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Thanks guys will check all the above over the weekend

 

[Goldwinger1984]

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Good luck on finding the problem, lots of decent suggestions stated above.

I wonder what happens if you simply unplug the spark plug wire to the cylinder that's glowing? I'd be interested in hearing what happens then.

Vic