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Thread: /6 cylinder temp

  1. #1
    Registered User skotlyc's Avatar
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    /6 cylinder temp

    Hello all. After spending all winter completely rebuilding my 75 r60/6, I'm finally getting a chance to get it out and ride it with the nice weather. I am noticing however my right cylinder is running just a tad hotter than you left. According to my IR gun,by 10 degrees. Is this OK? My spark plug isn't white and other than a little bluing on the right header, I wouldn't know the difference. Both header pipes are discoloring, the right slightly darker... they are cheap MAC aftermarket. Whatdya think?

  2. #2
    Airmarshal-IL James.A's Avatar
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    My wild guess would be that the right cylinder is running leaner than the left. I've seen this before on a 600 with type 53 Bing carbs. The best answer would be to send them to Bing for a re-build. You could get a kit and try it yourself as well. Y'know, soak 'em and blow out every passage with Gumout and/or compressed air. Be careful, there is a tiny accelerator pump built into the main jet stack. The other guy I knew who had this issue installed the Mikuni conversion. His bike had set for 30 years with rotten fuel in the system, so those carbs were hopelessly blocked up internally.
    1973 R75/5

  3. #3
    Registered User skotlyc's Avatar
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    I completely rebuilt the carbs myself after soaking them for a week each in Berrymans.

  4. #4
    Liaison 20774's Avatar
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    I'm not sure 10 degrees is much to be concerned about. Might just be that the new "toy" is providing you something to worry about. Be sure the carbs are balanced by the best method you know of and that should be about as far as you need to go. I wouldn't worry about something so minor.
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

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    Registered User skotlyc's Avatar
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    I didn't think it was a huge deal... it runs way to well for me to be concerned too much.

  6. #6
    I am not sure anything to worry about. Get some hundreds (thousands?) of miles on it, carefully watching things as you go. Be sure carbs are correctly adjusted. If you did a rebuild, rings, ect., it simply could be break in that is a little tighter on right side.

    If is sounds OK and rides OK with no visible issues, ride!!!

    Be sure to re-adjust everything (valves, carbs, etc.) after a few hundred miles.
    "The difference between death and taxes is that death doesn't change every time congress meets." - Will Rogers

  7. #7
    Airmarshal-IL James.A's Avatar
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    Quote Originally Posted by skotlyc View Post
    I didn't think it was a huge deal... it runs way to well for me to be concerned too much.
    Well then, why post?
    One pipe blueing more than the other always indicates an issue, which is one cylinder running hotter than the other. Plain and simple.
    1973 R75/5

  8. #8
    Quote Originally Posted by James.A View Post
    Well then, why post?
    One pipe blueing more than the other always indicates an issue, which is one cylinder running hotter than the other. Plain and simple.
    Not necessarily true. There are a lot of factors that affect the "blueing" of the exhaust pipes.

    Not saying that there isn't a problem, but to me, highly unlikely. There needs to be some break-in done to let all the wear surfaces to smooth out and seat with each other.
    "The difference between death and taxes is that death doesn't change every time congress meets." - Will Rogers

  9. #9
    Registered User Rod Sheridan's Avatar
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    Quote Originally Posted by skotlyc View Post
    I didn't think it was a huge deal... it runs way to well for me to be concerned too much.
    10 degrees F isn't anything I would worry about as a temperature differential.............Rod.
    Work is the curse of the riding class

  10. #10
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    I have also messed around with an IR gun with the bikes . With the R80 the temperature difference between cylinders has been close to 10 degrees , sometimes a little less ; usually right around 300 degrees by the time I get the bike into the back yard , and get the gun . Can't remember which side was hotter , because I did not find the difference meaningful . Which way the wind is blowing or if you are aiming at exactly the same spot are variables too difficult to resolve . Aimed right above the exhaust nuts , between fins . Would be even more difficult while in motion .

  11. #11
    Liaison 20774's Avatar
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    Hmmm...EGT or exhaust gas temperature probes?? Has that been done on an Airhead before?

    Now back your regularly scheduled thread...
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  12. #12
    Registered User godfather's Avatar
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    Quote Originally Posted by James.A View Post
    Well then, why post?
    One pipe blueing more than the other always indicates an issue, which is one cylinder running hotter than the other. Plain and simple.
    With aftermarket products, (say made in China) is it possible the quality of plating may vary enough to cause the difference in bluing at the same temp.
    Attitude is everything!

    08' V-Strom 650 great light weight tourer

  13. #13
    Airmarshal-IL James.A's Avatar
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    Quote Originally Posted by godfather View Post
    With aftermarket products, (say made in China) is it possible the quality of plating may vary enough to cause the difference in bluing at the same temp.
    The bluing of the header is what we might call a "heat affected zone". The quality of the plating would more likely affect the appearance of the heat affected zone. Example: the heat zone on the header of my 1988RS is a light brown rusty color all the way from where it starts to bend leaving the head to the crossover pipe. On my /5, it is a deep blue in the same area. For what ever reason, the 1000 cc motor has cooked the plating down to nothing. Both are original headers and both have considerable miles on them.

    With respect to the original post, the spark plug coloring will ultimately tell. I'm not sure I would give it much worry if the motor runs well otherwise. The type 53 mechanical Bing carburetors can be pretty fussy and inconsistent in my experience.
    1973 R75/5

  14. #14
    Smoooooth at 430 gch71's Avatar
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    I wouldn't worry about it to much to be honest.... I've got a 74" R60/6 that's been in the family since new and it always had the right side discolor quicker then the left, one thing to keep in mind is where the crank case vent goes.... but a difference of ten degrees is not an issue. I was actually thinking about placing an EGT probe temp system on my bike (like they use on GA aircraft for quality). But decided against it as I want to keep it original and I didn't want to start worrying about 'false imagined problems", I might do it on my 75/5 project though.
    Glenn
    ...driving to work on my airhead
    '73 R75/5, '74 R60/6, '75 R60/6, '80R65

  15. #15
    10F is not significant overall. if it was 40F or above, there may be a reason. i put an old military aircraft dual CHT gauge in the vent hole on my 81 R100RT just for fun (and it looks way cool to match the large oil pressure gauge on the other side). i was running 40F or greater on one side. turned out that side had the choke cable end sitting on top of the choke ferrule making that side RICHER! yes, richer equating to hotter. once i slipped the cable back down, the cylinder temps evened out.

    for the most part, they run the same but i notice that a sidewind will cause the downwind side to run hotter. also noticed that idling 5-10 minutes doesn't really overheat the cylinder as there seems to be enough dissipation to keep things in stasis. yes, you can FEEL heat rising off the cylinders but the actual temp doesn't rise that much over running down the road.

    -dan

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