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Thread: 1982 European R100RS

  1. #1

    1982 European R100RS

    Does anyone know for sure what the compression ratio is on the European version of the 1981-1984 BMW R100RS ?

    USA is 8.2 and am thinking Euro may be 9.5? or 9?

    If you own one, do they have any special problems beyond the valve seats?

    Thanks.................................George

  2. #2
    Registered User lkchris's Avatar
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    It's 9.5. Needle jet position is one click higher than on USA models, otherwise same carbs. Rest of engine is identical save for head ports for the air injection. No air injection means a little less heat around exhaust valve, but otherwise same materials.
    Kent Christensen
    21482
    '12 R1200RT, '02 R1100S, '84 R80G/S

  3. #3
    Hello Kent,

    Thank You, now I know for sure it is the 9.5...............George

  4. #4
    B Reams brook.reams's Avatar
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    Minor Typo ??

    Quote Originally Posted by lkchris View Post
    It's 9.5. Needle jet position is one click higher than on USA models, otherwise same carbs. Rest of engine is identical save for head ports for the air injection. No air injection means a little less heat around exhaust valve, but otherwise same materials.
    Just a minor nit, but I think you meant the "jet needle position ..." as the needle jet is kinda fixed in place

    Best.
    Brook Reams
    Brook Reams - Arvada, CO
    Endeavor to Persevere
    Various Two-wheeled Vices, All BMW
    2004 R1150-RS||2002 F650-GS||1983 R100RS||1977 R100RS||1975 R75/6||1973 R75/5

  5. #5
    Do these have 38mm or 40mm exhaust ports?

    Should it have a kick starter, or was that optional?

  6. #6
    Sir Darby Darryl Cainey's Avatar
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    The exhaust on my European 1984 R100RS was 38mm and it came with a kick start.
    Ambassador BMW MOA Ontario Canada
    President Niagara BMW Riders #298
    Knights of the Roundel #333
    1977 R100RS, (Retired) 1993 R100GS (just getting started)

  7. #7
    Registered User lkchris's Avatar
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    Quote Originally Posted by ghlubik View Post
    Do these have 38mm or 40mm exhaust ports?

    Should it have a kick starter, or was that optional?
    40 mm exhausts were only on the earliest R100s. The dual crossovers on the Nikasil engines made that redundant.
    Kent Christensen
    21482
    '12 R1200RT, '02 R1100S, '84 R80G/S

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