Red glowing S-header

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Today I tested my charging system too look for lost energyon my 1970 Commando S type.
After a night ride with mostly high-beam on the battery was flat.

After charching the battery I had the bike running on it´s mainstand and revved it up to 3000 -4000 rpm after warming up.
A test ride was not possible because of a dropback to winterly conditions here in Germany.

Test was fine so far but I stopped it because the right hand header was glowing red!
It was discoloured before. The left header shows only minor discolouration.

Normal because of the narower curve of the S-exhaust sytem or something wrong with carb adjustment?
Bike runs fine and has a good idle at 1000 rpm. Boyer-Ignition is timed correctly. 2 Amal 930 carbs.
Any thoughts, gentlemen?
 
The first time I got my commando running it sounded good but in less than a minute one pipe was glowing. I had to remove the press in plugs on bottom of carb bodies to clean a bunch of debris in pilot jet cavity. Drilled small hole, small screw to pull cap, epoxy cap in. Try spraying carb cleaner after cleaning pilot jet and see if it comes out the progression hole.
 
Low battery charge and a Boyer equals a ton of ignition advance.
I once had the battery on my '73 fail while riding and as the bike started to miss fire, I looked down to see one of my headers cherry red. A new battery resolved all problems.
 
Glowing exhaust usually means lean mixture or retarded timing.

If one side only, then lean mixture on that side is the likely culprit

lean mixture can be caused by too little gas (plugged jet, dropped needle or clogged filter) or too much air (vacuum leak or unbalanced throttle cables)
 
Yes the danger if driven is a burnt/seized valve or piston damage on that side. Likely pilot jet or needle clip popped off. Also a gentleman does not ride after dark !
 
BillT said:
Glowing exhaust usually means lean mixture or retarded timing.

If one side only, then lean mixture on that side is the likely culprit

lean mixture can be caused by too little gas (plugged jet, dropped needle or clogged filter) or too much air (vacuum leak or unbalanced throttle cables)

+1

Slick
 
gripper said:
Will not a over advanced spark give red exhausts too?

Yes it could, but would be a bear to start an over-advanced engine - you would keep getting kick-back.
 
gripper said:
Will not a over advanced spark give red exhausts too?

I have to disagree with others on this .... over advanced spark will make the internal (inside the cylinder) temperature higher than normal, but the exhaust temperature may be less than, normal, or higher than normal.


The reason overly retarded timing affects exhaust gas temperature is because fuel takes a finite time to burn. With overly retarded timing, fuel is still vigorously burning as it passes into the exhaust ports and headers, raising the exhaust gas temperature, but the internal cylinder temperature is lower than normal, since less fuel was burned in the cylinder as compared to normal timing.

With overly advanced timing, virtually all the fuel burns in the cylinder. This causes a slight increase in cylinder temperature as compared to normal, because a small amount of burning fuel leaves the cylinder with normal timing. However, a larger temperature change occurs in the cylinder with overly advance timing because the first fuel to burn is working against the crankshaft rotation. In effect, the other cylinders must put work into the cylinder to turn the crank past TDC. This additional work input raises the cylinder temperature higher than normal. The exhaust gas temperature is not so predictable.

In short, with late timing the header pipes run very hot because fuel is burning get in the headers. With very advanced timing, the exhaust temperature is reflecting the events inside the cylinder.

Slick
 
Air cooled MC such as our Nortons...
A glowing pipe at night is normal and IMO desired and an indicator your bike is running good or great.
The problem is most people, based on the responses here, don't know what really is normal.
A night time very dull dim red is acceptable but a bright red seen in the daylight is no doubt a precursor to a melt down.
No color at all... ever... is a very rich cold running engine (sub 900deg f EGT ) and is way down on power and crappy gas mileage.
Your engine if running well, the pipes will blue... but chrome that stays pure chrome is cold.
If you dyno an air cooled engine, only use a brake dyno :!:

Bikes like my liquid cooled Ducati can use a inertia dyno, but on my brake dyno, the pipe is a much brighter red then the norton can stand.
 
I guess it is a carb adjustment problem. Here are the plugs:
The left plug in the pic is from the right cylinder and vice versa.

Red glowing S-header
 
Left plug too rich, right plug looks ok to me but difficult to tell in picture, maybe lean.
 
Late combustion causes a rise in EGT.

Late combustion can be a result of late ignition timing,

Or slow combustion from a weak or rich mixture or low compression or - even a weak spark.

I don't know that I have ever seen a rise in EGT from overly advanced timing unless it was way over-advanced.
Maybe 20 degrees to fast which is also going to cause other problems very quickly. [severe piston overheating]

But, as Dyno dave says. A glowing exhaust is normal in a good running motor particularly if there is no air motion to help cool it.
I can normally look down at my exhausts at night after a little in town traffic and see them glowing slightly.
 
peter12 said:
Left plug too rich, right plug looks ok to me but difficult to tell in picture, maybe lean.

One plug is too rich and the other is good.
Why?
What we must do to to have less rich?.
Adjust the float level?
A better pilot clean?
Thanks.
Piero
 
xbacksideslider said:
Agreed, dull, almost invisible, dark cherry/purple glow seen at night is normal/why the pipes blue.

+1.
And I'm sure I've seen glowing headers on films of WW2 Rolls Royce Merlin engines.

Now, to the pics of the spark plugs: the sooty looking plug is the one from the right hand cylinder, which is the one with the glowing header.
That would tie in with what Comnoz said about a rich mixture causing slow combustion, whereas I and others immediately thought "lean mixture".
So if the mixture is corrected on that cylinder, it may stop the header from glowing, but that may not necessarily be a good thing.

My head is hurting now :D
 
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