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#267404 - 07/29/09 8:47 am Need some help understanding glowing red exhaust pipe  
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btour Online content
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The bike has been running tip top. And the start of the journey was no exception, but a sort of overall lack luster set in steadily. The right side has seemed a little draggy sometimes lately.

Anyway, I am going up a hill, doing about 3500k in 2nd, and I happen to look down and the right pipe is glowing. I increase rpm's to get it up more on the needle, (problem starts about 1/8 on throttle) rpms up to 4500. No change. Still red. It gets bigger and smaller but it remains. The only thing that stops it seems to be snapping the throttle closed. The left one does the same thing but only briefly and stops, and not again. Just the right.

When I got home, I try turning the idle air out a bit at a time, and keep testing. I get about 5 hours on the clock out and it is smaller but still there.

I am thinking it is the atmosphere. I am hoping it is. And the bike is running rich. I am thinking I can not correct it all with idle air, but would have to have a bigger cutaway on the slide to handle this.

When I started the trip the humidity was 75% Temp about 75. The bike was running OK then. When I got home I checked and humidity was 100%, temp about 70 degrees. The average weather so far this season has been damp but much cooler. So I am thinking the warmer air is holding more water (than the cooler air) and there is less oxygen to burn, so I have unburned gas in the pipe and that is what is glowing.

Else I just got unlucky and got some real bum gas. But the left side seems to be handling it Ok, if not great.

Or I have a torn o-ring in the idle air, or idle speed screws?

But would that make it run rich, and cause that glow?

Any ideas?

Last edited by btour; 07/29/09 7:27 pm.

Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
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#267409 - 07/29/09 9:14 am Re: Need some help understanding glowing red exhaust pipe [Re: btour]  
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norton bob Offline
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Weak carb or bad timming, check the easy things first,needle position too low in slide,air leaks,low fuel level, cuttaway too big, fuel flow. check with strobe timming same on both cylinders.try swapping carbs over, clean filters.Need to fix before bike siezes.Also check for tight Ex valve clearance is compression equal when hot?

Last edited by norton bob; 07/29/09 9:20 am.
#267414 - 07/29/09 10:11 am Re: Need some help understanding glowing red exhaust pipe [Re: norton bob]  
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Ger B Offline
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When I still had my electronic touching element thermometer I measured the outside of the exhaust bends just after the cylinder head once, directly after stopping the motor.
The temperature was 240 degr C (460 F for the non believers).
Red hot means your pipe has been over 500 degr C (930 F).
This is not caused by a carburettor issue, but by a flame of burning gasses. It could be your ignition is way to late, but in that case both pipes would show the same symptoms.

I think one exhaust valve:
- does not close due to inadequate tappet clearence, or
- is damaged allready because of inadequate tappet clearence, or
- siezes in the guide.

Don't wait to long.


Ger B

#267416 - 07/29/09 10:30 am Re: Need some help understanding glowing red exhaust pipe [Re: Ger B]  
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Are you running points? If so my money is on a retarded ignition timing due to the points gap opening up.

Bob


Phatt Bob
'95 Daytona 1200
'98 Daytona 1200 dragbike
ex-850 T140 Caff Racer, 850 Triton, Morgo T120, Starfire and Pretend Daytona 500 owner
#267427 - 07/29/09 12:01 pm Re: Need some help understanding glowing red exhaust pipe [Re: Phatt Bob]  
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dave jones Offline
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I agree on the retarded ignition but Phatt Bob means that when the points close up the ignition becomes retarded. Retarded ignition will also give darker plugs as though you are running rich. Check the timing and tappets and then the carb.


Last edited by dave jones; 07/29/09 12:03 pm.
#267434 - 07/29/09 12:16 pm Re: Need some help understanding glowing red exhaust pipe [Re: dave jones]  
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I agree with Ger, check your exhaust valves.

I had a similar problem where I bent exhaust valves through over revving. I'm not suggesting you've done this but valves may not be seating for some other reason. Motor would still run, with slightly less power, but headers glowed red under load.

#267480 - 07/29/09 4:05 pm Re: Need some help understanding glowing red exhaust pipe [Re: dave jones]  
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Originally Posted By: dave jones
I agree on the retarded ignition but Phatt Bob means that when the points close up the ignition becomes retarded. Retarded ignition will also give darker plugs as though you are running rich. Check the timing and tappets and then the carb.



Originally Posted By: Phatt Bob
Are you running points? If so my money is on a retarded ignition timing due to the points gap opening up.

Bob


Hi Guys,

No points. I have a Sparx ignition. One would assume it would not change. No one has been in there. The issue did seem to happen fairly rapidly. Although both pipes have been blue. The right side since the get go of the rebuild. So the glowing pipe, may have been going on and I just never happened to look down to see it. The right pipe has been barking. And that side seemed punkier. But I have been warned about my subjective judgements so I just, chose to try to ignore it.

Last time, the ignition timing was found to be too advanced. I assumed it was caused by me not revving it high enough, when it was set. Has anyone heard of Sparx, changing their advance all by themselves? This has been a concern in the back of my mind for some time now.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#267481 - 07/29/09 4:06 pm Re: Need some help understanding glowing red exhaust pipe [Re: bobsbrotherbob]  
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Hi Everybody,

And thank you for all the comments so far.

B'sbrobob ( You gotta post another moniker, that one is too long to type :), and Ger, I had a glowing pipe same side in aother incarnation of the engine. Checking and setting valves seemed to make it go away. But that is the side that blew the piston, too. Weather was similar in high humidity, but those other times it was COLD temp, and this time was fairly hot. I can hear the valves, clacking. In fact they are rather loud right now, but I just chalked that up to my aging senses, snd the way sound carries in humidity. There is a whirring sound in rockers, too. So I think the gaps are not too tight. I will check for sure. Even though I have been doing my utmost to follow the "prime directive" and just ride the bike and not fool with it, lest I damage it. Last time I did the valves, was about 1500 miles ago.

Valves may be sticking the guides. I wonder how atmosphere would effect that? The guides were done on the tight side of tolerances.

Before I check valves, I am tempted to go fill up tank with some gas from a different station. But that is probably not the issue.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#267483 - 07/29/09 4:19 pm Re: Need some help understanding glowing red exhaust pipe [Re: norton bob]  
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Originally Posted By: norton bob
Weak carb or bad timming, check the easy things first,needle position too low in slide,air leaks,low fuel level, cuttaway too big, fuel flow. check with strobe timming same on both cylinders.try swapping carbs over, clean filters.Need to fix before bike siezes.Also check for tight Ex valve clearance is compression equal when hot?


Bob,

You think the mixture is too lean? I was thinking it would be the opposite problem, too rich, if it a carb problem. With too much gas and not enough air to burn it, so it burns in the pipes. Leaning the idle air, did seem to reduce the glow. Can you tell me why, too lean would cause the pipe to glow? I want to understand this phenom.

Air Filters are new, only like 2k ago at most. Stock air box setup.

Needle in middle position with #3 cutaways. manual calls for needle in #! and #3 cutaway, so that would be even leaner. Could be off in both, needle and idle air ( and cutaway). Like I said. started doing this in 1/8 throttle, and increasing did not make it go away. Tune was set on hot and dry days. This was really humid and fairly hot, so it may be off. But I am thinking needs to go leaner, with 3.5 slide. So this is important for me to understand. Please explain.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#267490 - 07/29/09 5:19 pm Re: Need some help understanding glowing red exhaust pipe [Re: btour]  
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I still say check the timing first- it's dead easy. If you say it came on suddenly maybe it slipped.

Last edited by dave jones; 07/29/09 5:22 pm.
#267497 - 07/29/09 5:34 pm Re: Need some help understanding glowing red exhaust pipe [Re: btour]  
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If you would like to read more about this Triumph adventure it is here:

Triumph adventure of the glowing exhaust pipes, in the hot NoHo Night.

I guess I have my summer memory now.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#267498 - 07/29/09 5:35 pm Re: Need some help understanding glowing red exhaust pipe [Re: btour]  
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Originally Posted By: btour

Or I have a torn o-ring in the idle air, or idle speed screws?


Hi Bob,

AIUI, the o-rings are not there to seal air out or in. They are there to keep the screws from moving with the vibes.....

A torn o-ring should not affect carburration.....(unless the screw moves from it)

Steve


'77 T140J
"Vintage Bike". What's in your garage?

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
#267501 - 07/29/09 5:38 pm Re: Need some help understanding glowing red exhaust pipe [Re: btour]  
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Hi Dave,

I was not aware an EI can slip.

Sure it is easy, but first I gotta find a huge fan. Then I have to collect a buddy to hold the rpm's up. Then I gotta figure out how to set timing. I have never done an EI. And I have no idea what rpms is full advance for a Sparx.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#267530 - 07/29/09 7:21 pm Re: Need some help understanding glowing red exhaust pipe [Re: JubeePrince]  
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Originally Posted By: JubeePrince
Originally Posted By: btour

Or I have a torn o-ring in the idle air, or idle speed screws?


Hi Bob,

AIUI, the o-rings are not there to seal air out or in. They are there to keep the screws from moving with the vibes.....

A torn o-ring should not affect carburration.....(unless the screw moves from it)

Steve



Thank you, Steve, I will toss that out as a possible cause then. Screws are not moving by themselves. I got 'em memorized.

Finally got the rocker box cover gaskets to stop leaking so badly I have to clean the head before each ride. I think they healed themselves over time, with burned oil.

Now I am going to have to break the gasket. frown


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#267540 - 07/29/09 8:01 pm Re: Need some help understanding glowing red exhaust pipe [Re: btour]  
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I've got the eebee jeebees thinking of your 'buddy' twisting the throttle to check the timing, you can just give the motor big blips as you will see where the advancing stops without screaming it at 5k for 10 seconds while you peer at the disc.

Works for me.

Blapper redwine

PS use two big fans flat out, up close and pointing right at the engine.

#267544 - 07/29/09 8:07 pm Re: Need some help understanding glowing red exhaust pipe [Re: Blapper]  
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btour, isn't the stopping of rockerbox oil leaks the primary sign of no oil getting to them?

#267545 - 07/29/09 8:07 pm Re: Need some help understanding glowing red exhaust pipe [Re: btour]  
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One thing that puzzles me, is how the red comes and goes, with rythm of a living thing. Starting, stopping, growing, shrinking, like those creatures in Star Trek that fed on hate. The evil eye of Mordor.

One would think if it were, valves, timing, or mixture, it would remain fairly consistant.

Could it be just the pockets of humidity I was passing through? Although, even if that, I have to figure how to adjust for such high humdity, or stay home when it gets that way. Drat.

Maybe, this is why I switched from #3's to 3.5, and raised the needle to middle, long ago. High humidity and riding in the hill towns. I think it was Dave Moore from Conn. who recommended it. I cannot remember.

Bike was tuned at sea level in the dry and hot. It would not run with 3.5's with needle in middle position, I was told. I do not know if #1 postion was tried, but I assume so.

Last edited by btour; 07/29/09 8:11 pm.

Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#267548 - 07/29/09 8:16 pm Re: Need some help understanding glowing red exhaust pipe [Re: btour]  
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Hi Blapper,

How the heck do you manage that. Rotor is on lower left, and throttle is upper right. What are you, the stretch?

I got two middle size window fans so close to the engine, on each side, I am afraid the plastic one will melt.

I do not think they are enough for such high rpm's.

I got the heebie Jeebies too. Especially since my buddy has what is called they give children riddlin for, and I of course have early onset, Alzihiemers.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#267549 - 07/29/09 8:20 pm Re: Need some help understanding glowing red exhaust pipe [Re: btour]  
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Terry,

every time I check there is oil getting there. Still enough of leaking and weeping to confirm it.

IMHO, the bolts that hold the later style cover gaskets in place should be replaced with studs and locking nuts. That way thread sealer could be added, since it is not a blind hole. And it would making hanging the cover and gasket, even easier.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#267570 - 07/29/09 10:44 pm Re: Need some help understanding glowing red exhaust pipe [Re: btour]  
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Hell---what is all this about the effect of humidity?
These engines were designed to cope with everything from minus temperatures to hot temperatures with all sorts of humidity levels.
IME humidity wont make the difference between red hot exhausts and not red hot. If you have red hot exhausts then you have carb or timing problems unless you have what I came across in the UK in the 1960s which was new pattern exhaust pipes which were so thin they went red hot.
Look for something more basic to explain the problem---humidity is not the culprit.
Think of England where these bikes were designed and originally tested. Humidity is 100% for approaching 95% of the time!----just like the North East at the moment!

#267573 - 07/29/09 11:02 pm Re: Need some help understanding glowing red exhaust pipe [Re: Tridentman]  
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i was thinking the same tridentman, here in scotland we got almost 100% humidty all the bloody time lol.
btour, i had a t140 years ago that showed the same symptoms. it was a weak mixture that was causing it, the bike had the god awful bing carbs on it. you say you changed from a #3 cutaway to a #3.5?
that will be weakening your mixture straight away.
you asked for an explanation as to wjy weak mixture would cause the pipes to get hotter than a rich mixture, well quite simply more oxygen will make a flame more intense, look what happens when you light a oxy acetylene torch then turn the oxygen on!

#267577 - 07/29/09 11:19 pm Re: Need some help understanding glowing red exhaust pipe [Re: mick2]  
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Mick2,

Thank you but please read my posts more carefully. You got it backwards. And I did not do the switching. But please read my posts.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#267578 - 07/29/09 11:25 pm Re: Need some help understanding glowing red exhaust pipe [Re: btour]  
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Hi Tridentman,

Thank you, but I am little sick of the attitude that I am blaming the bike or the design of the bike. Is there anywhere I said it could not be tuned?

Respectfully, I and I mean that. Would you tune the bike the same way for England as you would say for Arizona? Same slides? Or for say, the shore, as for say top of the rockies.

The only variable here between great running and pee poor is the change in heat and humidity. And a fill up at a gas station.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#267580 - 07/29/09 11:34 pm Re: Need some help understanding glowing red exhaust pipe [Re: btour]  
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Sorry Mick,

That was a bit curt.

The manual says #3 slides and 1st postion. Sometime 25 plus years ago, I had, emphasis on had, long time ago, changed to 3.5 slides and middle postion. It remainded that way until rebuild.

At that time it was determined that bike would "not run" with a 3.5. So a #3 was chosen. That tuning decision was made a couple of months ago. I have not changed anything since. Nothing. Not one thing,


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#267583 - 07/29/09 11:41 pm Re: Need some help understanding glowing red exhaust pipe [Re: btour]  
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You've got it bassacwards, too lean runs HOTTER, can melt pistons and burn valves. Too rich is cooler, fouls plugs but will not cause a melt down. It's called a pilot AIR screw, screwing it in cuts off the air and it runs RICHER, screwing it out lets in more air and it runs LEANER. Too lean = red hot or even white hot and death. I think you should put the needle back in the center clip position also. The 3 1/2 cutaway also makes it LEANER,and that kicks in at about 1/8 throttle, go back to a 3 if you can.
Forget the weather, altitude maybe, but not till you get over 5,500 feet or so.
While I was writing this three more posts hit but some of it still applies. Good luck.

Last edited by desco; 07/29/09 11:44 pm.

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