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  1. #1
    Bon Vivant
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    What Happens?

    I have a 2002 R1150RS that I absolutely love. I have a question regarding the battery and I can't find an answer through the Search tool. My manual says that if the battery is disconnected, the bike will undergo a memory loss and not function correctly. Really? Does it have to be reset or will it self-correct? Thanks for your thoughts. - Murfee

  2. #2
    Registered User SeabeckS's Avatar
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    Quote Originally Posted by Murfee View Post
    I have a 2002 R1150RS that I absolutely love. I have a question regarding the battery and I can't find an answer through the Search tool. My manual says that if the battery is disconnected, the bike will undergo a memory loss and not function correctly. Really? Does it have to be reset or will it self-correct? Thanks for your thoughts. - Murfee
    The Motronic will lose it's memory I think. To reset, once the battery is reconnected, turn the ignition key to ON, but do NOT start the bike. With the key on, rotate the throttle to full open and close a couple of times. Turn the key off, and voila the throttle sensor is reset. Now you can start the bike....
    Bill Johnston

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    Left Coast Rider
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    Quote Originally Posted by SeabeckS View Post
    The Motronic will lose it's memory I think. To reset, once the battery is reconnected, turn the ignition key to ON, but do NOT start the bike. With the key on, rotate the throttle to full open and close a couple of times. Turn the key off, and voila the throttle sensor is reset. Now you can start the bike....
    Really? I replaced the battery on my S a couple of years ago and didn't experience any issues.

    Edit: After doing a little googling it appears SeabeckS may be onto something here.
    Last edited by BC1100S; 06-13-2013 at 04:21 PM.

  4. #4
    Registered User lkchris's Avatar
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    Quote Originally Posted by BC1100S View Post
    Edit: After doing a little googling it appears SeabeckS may be onto something here.
    Googling? Try looking in BMW service literature.
    Kent Christensen
    21482
    '12 R1200RT, '02 R1100S, '84 R80G/S

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    Registered User SeabeckS's Avatar
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    Well, since I just replaced the battery in the S last weekend....

    Though I wasn't entirely sure this advice would be relevant for an RS, they're such strange beasts.
    Bill Johnston

  6. #6
    Left Coast Rider
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    Quote Originally Posted by lkchris View Post
    Googling? Try looking in BMW service literature.
    That's not nearly as much fun as sifting through mountains of misinformation, opinions, and old wive's tales before finally happening upon that kernel of wisdom which leads to a bona fide answer.

    Here's a question: When I replaced my battery I didn't do the open-the-throttle-a-couple-of-times procedure. Bike seems to run fine and dandy (and much better than those schoolbus yellow/lead pencil grey models). Should I disconnect the battery and run through this procedure or might I be delving into "if it ain't broke - fix it 'til it is" territory?

  7. #7
    Registered User SeabeckS's Avatar
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    It ain't broke IMHO...

    Though it could use a paint job to cover up that pathetic blue color!
    Bill Johnston

  8. #8
    Registered User roger 04 rt's Avatar
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    Quote Originally Posted by Murfee View Post
    I have a 2002 R1150RS that I absolutely love. I have a question regarding the battery and I can't find an answer through the Search tool. My manual says that if the battery is disconnected, the bike will undergo a memory loss and not function correctly. Really? Does it have to be reset or will it self-correct? Thanks for your thoughts. - Murfee
    On the R1150 series of motorcycles (and the R1200s and the R1100S with Motronic MA 2.4), my tests and the service literature are very specific. When you disconnect the battery (or remove Fuse 5 which powers the Motronic) you will lose "Adaptation Values" (see quote from Service Manual below) and the TPS "registration". You lose them because they are stored in memory powered by the 12V main battery.

    Losing these values does no harm, and causes no permanent effect (and can be helpful at times). The TPS is reregistered (whatever "reregistered" means) after a battery disconnection by turning the Key to ON but not starting the motorcycle and turning the throttle twice from fully open to fully closed (fast idle lever fully down); then turning the Key OFF, then starting as normal.

    The Adaptation Values are relearned after the motorcycle is fully warmed up and you ride it for a while (1/4 tank of gas gets a lot of the relearning done but not all).

    These Adaptation Values are learned when the Motronic compares two calculations that it makes: 1) how much fuel the O2 sensor says is needed (Closed Loop) to hit an AFR of 14.7:1 and 2) how much fuel is needed when it uses fuel table plus air sensor plus barometer plus battery voltgage (Open Loop). The Adaptation Values are applied to Open Loop fueling: Cold Start, Acceleration, Deceleration, throttle open more than 50/60 degrees.

    VERY SIMPLY, say you are riding steadily at 8 degrees throttle and 3000 rpm, if the Closed Loop fuel pulse to hit 14.7:1 is 2.575 milliseconds but the Open Loop calculation says it should take 2.500 milliseconds, the Motronic "learns" that it takes 3% more fuel to hit 14.7:1 than the fuel tables and sensors say. Because the O2 sensor is very accurate, the Motronic remembers an Adaptation Value and saves it in the temporary memory. The next time it has to calculate fuel without the help of the O2 sensor, it applies that 3% learned number.

    That process also happens at many RPMs and TPS levels, including IDLE. Therefore after you ride for a while, after a battery disconnect, the starting and idle get better.

    So disconnect without fear, just reregister the TPS and ride for a while.
    RB

    PS. Although I haven't measured it myself, the Motronic MA 2.2 on the R1100 surely stores some Adaptation Values. It's pretty hard to make an FI computer work without at least some learning. More later after I get an LC-1 on an R1100. The Bosch engineers designed the software to do this 15 years before any Oilhead was produced.

    Quote from BMW Service Manual

    Note:
    Disconnecting the battery means that the entries in
    the fault memory of the Motronic MA2.4 control unit
    are deleted and the adaptation values are reset.
    This can temporarily impair the operating characteristics
    when the engine is restarted.

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