Topic: header temperature

[Deltarider]

Nobody said anything about fine tuning, just an indicator of a lean condition.

Kelly, may I invite you to make a video - a few seconds will do - in which is demonstrated that a leaner condition results in a higher header temperature measured by your infrared gun? Depending on the bike model you own, you can turn the airscrew to arrive at a rich and a lean condition respectively. Thanks in advance.

Why do you always want to argue about stuff? I just like the resurrect old dead bikes and ride them. Not argue about it. You take the fun out of it.

Kelly, you misunderstood me. I want to learn how to do it, because I didn't succeed. I have two infrared guns and I didn't manage to make sense of it.

[Kelly E]

I don't have a infrared temperature gun. I was talking about pipe discoloration like this.
 On both the 77' KZ 1000 and the 80' GS 1100E we richened up the cylinders a little bit and the discoloration stopped getting darker.
Both bikes have the Delkevic exhaust system with Mikuni RS 34 on the KZ and RS 36 carbs on the GS. You have to wing it a little bit to get them sorted out. Both bikes run great now and will keep up with modern bikes.

[Deltarider]

Thanks for explaining, Kelly. I just wondered what I could learn, because I was never succesful in diagnosing by using an infrared gun and I have no knowledge of a professional workshop that uses it as a tool for diagnosing by aiming it at the headers.
For electrical misfires I don't need a tool. I can diagnose that by listening and check for arcing either between plugcap/HT wire and the head or at the breakerpoints. When in doubt I connect a strobe to the suspect plugwire/cap.
For irregularities due to carburation, a look at the plugnoses will tell me. But I do this check only at midrange.
For irregularities due to carburation at idle, I can check by turning the airscrew - one at the time! - fully closed and then say three turns out. If rpm does not change, there's something wrong in that particular idle circuit.
In the meanwhile the invitation is still standing: if anyone is able to shoot a video that demonstrates how turning the airscrew say a quarter of a turn in or out resp. resulting in a change of the corresponding header's temperature, it would be a great attribution to this forum.

[dave500]

once your moving and riding properly over 4 grand where the motor should be the idle screw does #$%* all!

[Deltarider]

once your moving and riding properly over 4 grand where the motor should be the idle screw does #$%* all!

Sorry to contradict you. A Honda mec who owned an CB500 with the 649A carbs himself, has told me the slow circuit is still of some influence higher up. He didn't explain how, but it runs parallel with the testing I have done in the past. K2-K6 in the UK forum once gave an explanation for the how* which is plausible to explain the findings I had in practice. It's for this reason, I think the scheme in fig.7 gives a better representation over others.
Not that I use the airscrews for adjusting the mixture for over 4000rpm, but for up to that, I certainly do, to arrive at a good driveability. Other models like the CB500K3 with their PD carbs may be different in this respect though.
*I'll see if I can find it.

[newday777]

once your moving and riding properly over 4 grand where the motor should be the idle screw does #$%* all!

Sorry to contradict you. A Honda mec who owned an CB500 with the 649A carbs himself, has told me the slow circuit is still of some influence higher up. He didn't explain how, but it runs parallel with the testing I have done in the past. K2-K6 in the UK forum once gave an explanation for the how* which is plausible to explain the findings I had in practice. It's for this reason, I think the scheme in fig.7 gives a better representation over others.
Not that I use the airscrews for adjusting the mixture for over 4000rpm, but for up to that, I certainly do, to arrive at a good driveability. Other models like the CB500K3 with their PD carbs may be different in this respect though.
*I'll see if I can find it.

Finally, you have explained yourself here and giving the attached link on carb 101 helps(maybe you have attached it before and like this time, we haven't seen it to open the attached in the small print below you text body). I gleaned all this in the mid 70s while taking time in the shop from the techs out back when I took breaks away from the parts counter. That carbs 101 attachment was a good refresher.
Each time you haven't gone this far in the past year makes your drum a clanging cymbal that grates against the brain like scraping fingernails on glass or a chalkboard. I, like Kelly, would cringe each time you have posted the same beating without fully explaining through it.
Part of the confusion comes into play when you mention your bike never needing carb servicing as you have kept it running properly all these years you have owned it when most of the posts were about clogged carbs from bikes that sat unused for many years, especially if the bikes were left setting with the old gas in them containing the old junk additives that the fuel was laced with here in the states during the 90s-2000s years and the reaction those chemical reactions had on carbs that sat for these many years abandoned and are now being brought back to life by many unschooled in carbs 101 and how to properly clean the brass and carb circuits to get them to run good.
Thanks for Finally taking the effort to explain yourself Deltarider.

[Deltarider]

Newday, you're right. I always make the mistake to assume everyone's bike here, is or has been a daily runner. Mine isn't btw, but it runs regularly enough to stay healthy. Nine out of ten issues I may have had, had to do with... standing and not with riding. Just the other day I've sent a copy of that 1994 article to friends. Its an interview with an owner who had bought his CB500 new in 1974, never did any maintenance himself, but had it done by his dealer and thanks to using his bike as a daily rider, had, the day when he was interviewed 220.000km on the odometer and the engine had not been 'opened' yet for anything but adjusting the valves. Mind you, he was not the only one in those years who easily covered over 100.000 miles without needing an overhaul. That's how utterly robust these engines were. The AA man, who was in the garage some years ago to assist my neighbour with his @#$!@ Smart, knew from daily practice how sturdy Honda engines in general are. He mentioned 'Honda Joe' an American who has made the press when his Accord had clocked 1.000.000 miles, that's 1.600.000km!
Looking at the issues I see so often coming by in this forum, I sometimes cannot believe it's about the same bike I have.
Without question, when carbs have been left unattended, you can expect a mess inside and they will need to be cleaned. Guess what, I've 'cleaned' my carbs when I had opened them out of curiosity... but, did they needed it? Mwah, hardly. It seems mine were kept clean by the passing gasoline. Yes, a few O-rings, especially those tiny ones around the main jets needed replacement, but that's it. All the brassware is still the same Keihin put in there, in 1975.
But, again, it's good you pointed me at this. I'll try to remember it. What really worries me though, is that he, who can sum up the most ''shortcomings", is automatically regarded here as an expert. But hey, that does not reflect reality. In my archives I have several rider reports to prove it. Two of these riders reports are about the CB500 and in the last one, respondents had distanced a combined total of 40 times around the world. Has also to do with that - in contrast of the US where a bike usually was an extra - lots of folks here had a motorcycle instead of a car.
What I also see here is - I suspect - cognitive dissonance.
The fact that a manual describes any possible repair, does not automatically imply you have to do all this. Most of what is in these pages, has been copy pasted from other manuals anyway. It's hardly ever commented on by mechanics that have serviced these bikes. Haynes comments occasionally.
My best source has always been the mechanics in the workshops. I had made it my strategy to, whenever I needed something like a filter or sparksplugs, I would visit the dealer, when they were sat having lunch. Then they had time to answer a question I had, or assure me. that something which maybe was a frequent issue with other bikes, they had never seen occur on my model. In those years they were not trying - again in contrast with the US - to sell you things, the thing they wanted above all, was to invest in a good relationship with you. A confession: when I had opened my topend myself (at around 80.000) to save costs and from there have the judgement and reassembly done by a professional mec in a Honda workshop, the first thing he asked me was, why I had opened it up. Red in my face I stumbled that I thought it was about time. He smiled whilst nodding his head. He had seen many that had done twice the distance.
The mere fact that there are Keyster carb sets in the market, does not automatically imply the same parts on yours wear fast. It's a conclusion some simply draw, because of the mere existence of these sets in the market. And ofcourse, they can't wait to do 'maintenance'. Ofcourse, anything better than having to assist in the household, right? Here again: very well cognitive dissonance is at play here. Therefore I cannot repeat enough: this forum is about our bikes and it is about us. Sorry for this lengthy answer.

[Mark K]

I checked my header pipes again yesterday out of curiosity (while trying to synchronize the carbs). While I thought I fixed the cylinder 4 low temp issue with replacing a clogged slow speed jet, the problem of different temps on cylinder 4 remains, at least 40* lower than cylinders 1,2&3. The engine runs okay, still not able to get it on the street due to me being a sloth when it comes to needing to clean the fuel tank, I'm not worried about the different temps for now.

[jjc]

I'll give you an idea.
I went to a guage compy that makes airplane guages & they put a motorcycle face on a guage and I had a duel temp head temp guage for my HD motor.
Now if you get a head temp guage from a shop & install one, you guys with your headers wrapped will find out something interesting.
If you guess correctly I'll tell you but otherwise, you'll have to contrast your findings with a buddy that did not wrap there exhaust.

[Schnell]

On my journey to get my bike, bought this summer, running and running well, a funny thing happened.

Bike was running great when suddenly on a ride it lost power and sounded like it was running on 3 cylinders. I nursed it home and took header temp readings to see which cylinder was affected. Luckily it was #1 so easy to access. I dropped the float bowl and there in the bottom was the slow speed jet. Vibrations had caused it to unscrew itself.

This was the jet I removed to check the size number. It was the same as on my spare carb rack from my parts bike, so I just screwed it back in finger tight, still with the carbs mounted on the bike. Obviously not tight enough.

This time I found a piece of metal that would fit in the jet's slot and offered my fingers a purchase to apply more torque. Hasn't fallen out since.