1981 R80 TIC Carb jetting

Discussion in 'Airheads' started by The Chimney Sweep, Apr 30, 2013.

  1. The Chimney Sweep

    The Chimney Sweep Adventurer

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    I recently acquired what I believed was a '1982 R80 RT'. As a matter of course, I replaced the worn jets in the carbs as per the motobins website and the [American?] information from the Clymers manual. Bike hasn't been run a lot, but seems to be running hot...

    Recently I entered my VIN into www.realoem.com, which says that my model is actually '06/1981 2477 R 80 TIC Europe'. The little literature I can find for the TIC either does not list jetting info for the bike, or gives conflicting information- unfortunately I'm not a wizard who can work these things out for himself...

    The camshaft on the bike right now is the 308 degree affair- part no. 11311 338 302 (I'm fairly sure the camshaft has been replaced at some point so this may not be standard for the model).

    Has anyone got any idea what the recommended jetting should be for this setup? and does the fact that the bike is running on unleaded petrol now affect any of BMWs reccomended values?

    Thanks for reading...
    #1
  2. chasbmw

    chasbmw Long timer

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    I'm pretty sure that TIC means ex police, I would jet the same as any euro R80 of that era. I don't believe that unleaded has any effect on jetting
    #2
  3. 190e

    190e Long timer

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    Standard cam was a 308.

    I also think TIC means ex police and that the jetting would be the same as a any other Euro R80 although there might be a small issue with that. I've read some anecdotal evidence to say that all R80's were not quite as economical on fuel as they should have been and that the reason for this was they adopted the jetting preferred by the police which was on the rich side for ease of starting and running without choke.

    My understanding of unleaded fuel is that if it has any percentage of ethanol in it then it will weaker than the original fuel as the calorific value of ethanol is approx. 30 % less than gasoline. In practice with E5 or E10 that just means the mixture is a few percent weaker which is probably moving in the right direction compared to the factory setup.
    #3
  4. 190e

    190e Long timer

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  5. boxerboy81

    boxerboy81 Stay Horizontal

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    r80 64/32/349-350.
    MAIN JET 150. NEEDLE JET 2.66. JET NEEDLE 241. atomizer 591. idle jet 40. needle 3rd position

    r80 64/32/353-354.
    main jet 135. NEEDLE JET 2.68. JET NEEDLE 251. atomizer 591. idle jet 45. needle 3rd position
    #5
  6. The Chimney Sweep

    The Chimney Sweep Adventurer

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    Many thanks to all- that's exactly what the doctor ordered... carb numbers!
    It's difficult to find parts by model and production year alone when the bikes were specced to order and have then had 30 years worth of tinkering and parts swapping!
    #6