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Thread: Hot exhaust headers on RT

  1. #16
    Benchwrenching PGlaves's Avatar
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    Quote Originally Posted by Manhattan Rider View Post
    The ECU is not adjustable, so it can't accidently run rich or lean unless he's running a Techlusion. Valve adjustments and throttle body adjustments have nothing to do with the amount of time fuel injectors stay open or closed.

    I
    I'll quibble a little bit. The system does not measure air flow. It assumes air flow based on the position of the single TPS on the left throttle body. The ECU assumptions about air flow depend on the TPS idle value and range, the proper adjustment of the valves, and the proper synchronization of both throttle bodies. The O2 sensor reads the exhaust stream and makes some correction some of the time.

    If valves are set out of spec, or if there are deposits on valve heads then air can be constricted but the ECU doesn't know it. If the two throttle bodies are not synchronized then one can be rich while the other is lean. And if there are gums or crud partially obstructing a fuel injector that cylinder will get less fuel even though the injector is staying open the right number of milliseconds.

    So there are all sorts of variables that can effect mixture without a Techlusion or any other aftermarket add-on. Most of them are dealt with with a complete proper "tune-up">
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://www.bigbend.net/users/glaves

  2. #17
    Manhattan Rider
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    Quote Originally Posted by PGlaves View Post
    I'll quibble a little bit. The system does not measure air flow. It assumes air flow based on the position of the single TPS on the left throttle body. The ECU assumptions about air flow depend on the TPS idle value and range, the proper adjustment of the valves, and the proper synchronization of both throttle bodies. The O2 sensor reads the exhaust stream and makes some correction some of the time.

    If valves are set out of spec, or if there are deposits on valve heads then air can be constricted but the ECU doesn't know it. If the two throttle bodies are not synchronized then one can be rich while the other is lean. And if there are gums or crud partially obstructing a fuel injector that cylinder will get less fuel even though the injector is staying open the right number of milliseconds.

    So there are all sorts of variables that can effect mixture without a Techlusion or any other aftermarket add-on. Most of them are dealt with with a complete proper "tune-up">
    Have you ever seen any of these variable you discribe above result in blistered side panels on an RT? I've seen side panels too many times to count on well-tuned RT blister at only 3 bars at idle by leaving the choke on. However, I've never seen an RT blister side panels even out of tune at 9 bars in standstill traffic in Washington D.C. Been there, done that for a full year on my RT with 133,000 miles and the side panels are not blistered.

    Again, the only logical reason for this problem is self evident in the owners own statement stating he idled the bike in his garage. Although he doesn't say it, the only way to get the headers to glow as desribed is by engaging the choke at idle.

  3. #18
    Benchwrenching PGlaves's Avatar
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    Quote Originally Posted by Manhattan Rider View Post
    Have you ever seen any of these variable you discribe above result in blistered side panels on an RT? I've seen side panels too many times to count on well-tuned RT blister at only 3 bars at idle by leaving the choke on. However, I've never seen an RT blister side panels even out of tune at 9 bars in standstill traffic in Washington D.C. Been there, done that for a full year on my RT with 133,000 miles and the side panels are not blistered.

    Again, the only logical reason for this problem is self evident in the owners own statement stating he idled the bike in his garage. Although he doesn't say it, the only way to get the headers to glow as desribed is by engaging the choke at idle.
    I'm not arguing that point at all. See my original post. These bikes should never be allowed to sit at idle very long, and certainly not at fast idle. But he also originally posted that the pipes glowed going down the road and I have seen glowing pipes from lean mixtures, not at highway speeds but at neighborhood speeds. The identified cause was throttle body imbalance with one side rich and the other lean.

    Related, but as an aside, the basis for BMW discontinuing the R1100RSL in the US before they did so in Europe is not urban legend. An owner started his bike, went in the house, answered the telephone, had a long conversation, and came back out to find the bike, then the garage, and soon the house on fire. The size of the print of the warning in the manuals got bigger after that I am told.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://www.bigbend.net/users/glaves

  4. #19
    Manhattan Rider
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    Schuk...is the blistering on your side panels on one side or both?

    Here's an interesting fact. Last winter, I was adjusting the throttle bodies on my R1100RT (side panels off). While warming the motor to five bars, I decided to see just how hot the header actually get with the choke full on. At three bars with the choke full on and the pipes glowing, my IR Thermometer registered 500 degrees. It could have actually been hotter, since my IR gun range is -4 to 500 degrees. With the choke off at five bars, both headers were around 300 degrees. Both throttle bodies were very close to being in synch. It would be a good experiment to intentionally adjust the throttle bodies out of synch and record the difference.
    Last edited by Manhattan Rider; 08-03-2011 at 12:14 AM.

  5. #20
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    Unhappy I'm having this same problem with a hot header blistering my paint

    Quote Originally Posted by PGlaves View Post
    I'm not arguing that point at all. See my original post. These bikes should never be allowed to sit at idle very long, and certainly not at fast idle. But he also originally posted that the pipes glowed going down the road and I have seen glowing pipes from lean mixtures, not at highway speeds but at neighborhood speeds. The identified cause was throttle body imbalance with one side rich and the other lean.

    Related, but as an aside, the basis for BMW discontinuing the R1100RSL in the US before they did so in Europe is not urban legend. An owner started his bike, went in the house, answered the telephone, had a long conversation, and came back out to find the bike, then the garage, and soon the house on fire. The size of the print of the warning in the manuals got bigger after that I am told.
    I know this thread is almost two years old but I'm having this same problem. I took my side panels off, sanded and repainted my crispy shark fins, and I also wrapped my headers. Got her all back together today I went on a 10mile mixed speed typical ride. The right side (if I'm sitting on the bike) seems to be the issue. I did not let it sit and idle, my oil temp was never above 5 bars, and it seemed to be running great. I got back home directly in the garage and shut her right off. Got off the bike and too that same side and the fin and the fairing next to the header was so hot I couldn't hardly put my hand on it. WTF is going on. I just had the valves and injectors done last fall. I replaced the plugs when I first got the bike. Went from Bosh R6 787 to NGK BKR7EKC-N. could that have anything to do with it? This is driving me nutz! I love this bike and I just want her fixed...

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