Preferred motor sourcing (replace) for Airheads?

Discussion in 'Old's Cool' started by Skylar, Sep 4, 2011.

  1. Skylar

    Skylar Tryin' not to die

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    Jul 31, 2007
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    67
    Location:
    Ann Arbor, Michigan
    I'm looking specifically for a solid R90S motor to build off of. I don't know many bikers or Airheads for that matter.

    Anybody here have decent luck sourcing just motors? I have everything else.

    Thanks for your time.
    #1
  2. JamesOn2Wheels

    JamesOn2Wheels Banned

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    dammit..back in the states
    there's a rebuilt r90 at IBMWR right now - complete rebuild, 0 miles
    #2
  3. Skylar

    Skylar Tryin' not to die

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    I see it. I (believe it or not) wasn't really aware of that place but it looks like a great resource- thanks so much.
    #3
  4. bmwrench

    bmwrench Long timer

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    Why an R90S?
    #4
  5. Skylar

    Skylar Tryin' not to die

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    He wants a 90S motor for it.

    We thought about a 100, but he's less concerned with top end, wants a mill that's faster off the line.
    #5
  6. wirewrkr

    wirewrkr the thread-killer

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    As far as the actual motor is concerned, the only difference between the actual S motor and a regular R90, is the slightly higher compression pistons and the intake spigots for the Delorto carbs. the rest is the same (except for black painted/coated cylinders)
    #6
  7. Skylar

    Skylar Tryin' not to die

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    An S motor will be rarer & likely more expensive than a 90 motor, so I guess he'll pull the trigger on whichever one comes in the right condition & price. Thanks for the info.
    #7
  8. Boxer Metal

    Boxer Metal Mad Scientist

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    f the bike is a 76 you might as well still a 1000cc in it. The bottom end would be the same as a 900.
    #8
  9. ducsingle

    ducsingle Been here awhile

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    Then he should opt for an R100 engine. Or find a bottom end and install a 1070 kit. Larger displacement = more torque = faster acceleration.
    #9
  10. DoktorT

    DoktorT BigBrowedNeandereer

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    and = less reliable, needs custom tuning, and much shorter life. Any stock 90 or 100 will bolt right in and be easy to set up stock and give the long term reliability they are famous for.

    If you go with a 90, do try for a 76 block. It will have the larger cylinder bores in the block so anything later is a simple bolt on situation.
    #10
  11. Rapid Dog

    Rapid Dog bikes, booze, broads...

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    #11
  12. Airhead Wrangler

    Airhead Wrangler Long timer

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    Back in Seattle, FINALLY
    I just picked one up off of ebay for $100 and it's in REALLY nice shape. It was another $50 to ship it, but hey it's most of an engine.
    #12
  13. PaulRS

    PaulRS Dutch fool

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    Fit the 100 and replace the FD with one from a 75 or 80?

    Paul.
    #13
  14. Stagehand

    Stagehand Imperfectionist

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    I would love to build an EbayCLIBMWR bike :D
    #14
  15. Skylar

    Skylar Tryin' not to die

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    We've been in touch with this gentleman, but it's a "1978 motor" but can't be a 900 because there wasn't a 900cc in '78.

    Has to be an 80 or 100 if the year's correct.

    Might have to pass on that one. I think he's set on a 900cc. Thanks for the heads-up though.
    #15
  16. Rapid Dog

    Rapid Dog bikes, booze, broads...

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    ...no, not a 900. Just thought if you were considering an R100 instead.
    #16
  17. Skylar

    Skylar Tryin' not to die

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    It might come to that. If it's a strong runner for that price, it might be the best thing going. Thank you RD.
    #17