Physical differences of type 247 (airhead) engines?

Discussion in 'Airheads' started by JLeather, Oct 18, 2012.

  1. JLeather

    JLeather Bike Butcherer

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    Are the physical locations of the intake and exhaust ports different between the airheads (R50, R60, R65, R75, R80, etc)? I'm asking because I want to put a Luftmeister turbo kit on an R60/5. The kit was technically only offered for '74+ bikes and only listed for R75, R90, and R100 with most of them being installed on R100's. I read that the location of the ports are the same for all the airheads, is that true? I know the diameter of the ports changed some and I may need to turn some spacers/sleeves for the exhaust and intake.

    I saw a Luftmeister kit on an R65 on eBay a few months back, and I know atleast one member here has one on an R100, which would lend some credence to the theory that the physical engines are no different. The durability and tuning issues I'll address later :)
    #1
  2. Rob Farmer

    Rob Farmer Long timer

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    Wouldn't it just be easier to buy a 1000cc bike if you want more go?

    or you could by a 1000cc bike and and then put the Turbo on it.
    #2
  3. Padmei

    Padmei enamoured

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    my r65 has shorter barrels than the 80/100. If that's what you mean?

    [​IMG]
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  4. JLeather

    JLeather Bike Butcherer

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    Where's the fun in that? Actually, though, I'm asking because I lucked into an un-used Luftmeister kit a while back and I have a kinda rough '72 R60/5 sitting here. Supposedly in some of the literature the kit fit "all type-247 engines". Just wanted to pick the brain of a few members before I dragged everything out of storage, tore the carbs/exhaust off of the R60/5, etc.

    Yes, but are the intake and exhaust ports in different locations?
    #4
  5. luxlogs

    luxlogs Been here awhile

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    Sorry I have no answer only more confusion, the kit you saw on the R65 was for a 248 engine.
    #5
  6. bmwrench

    bmwrench Long timer

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    The only problem you'll have with fit is that the R60 intake stubs are a lot smaller than the R100s; you're going to have a step down from the turbos tubes to the heads.

    If I was going to build such a thing, I would install (at least) R75 cylinders and heads, and since the R60 cam seems to be the culprit in the stock bikes tendency to ping, I'd probably install a 308 cam at the same time.

    Turboed twins are interesting performers, but I have to warn you that riding them can be compared to straddling a wood stove-seriously hot.
    #6
  7. JonnyCash

    JonnyCash turd polisher

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    How would cam profile contribute to pinging? I'm not asking thinking that to say that it wouldn't. I just don't know.
    #7
  8. _cy_

    _cy_ Long timer

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  9. JLeather

    JLeather Bike Butcherer

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    Thanks for the heads-up. The kit I picked up has the optional water injection hardware, which should help me some with the detonation and heat issues. I'm not building a tourer, it's just going to be a fun bike for short hops. If I blow the R60/5 motor I can always swap jugs/cam later. How big can I go on an R60/5 bottom end? R90 cylinders?

    The intake stubs, are they removable? I've almost got my new lathe up and running (went to a 14x40 instead of the little 10" I was running). If they are removable I could make new ones, or I could also just make some adapters.
    #9
  10. Solo Lobo

    Solo Lobo airhead or nothing

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    Inmate MNSTY has/had a turbo water injected R90S that has something like 90K miles on it and I beleive he is the second owner and has had no issues.

    [​IMG]
    #10
  11. bmwrench

    bmwrench Long timer

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    The shorter duration increases "dynamic comprssion ratio" by closing the intake valve before the piston pushes some of the intake charge back out.

    The Luftmeister turbo kits actually fairly well as long as you stayed with the "stock" 5 lbs of boost. Adding boost beyond that made carburetion difficult, required water injection, and caused severe detonation. The way the motor pulled was thrilling, and the sound of a boosted Airhead is rather intoxicating, although it always felt to me like the bike was being yanked along by the scruff of its neck. .
    #11
  12. JLeather

    JLeather Bike Butcherer

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    Well, for the most part the kit fits fine (in spite of being advertised only for later models). There are a few small nagging issues. The exhaust after the turbo interferes with the kickstarter. I like the kickstarter, so I'll be re-routing the exhaust. The intake spigots are way too small, so I'll be machining some larger ones with a nice taper inside to preserve some sort of flow characteristics. The turbo also hits the stock size/location of the battery, but that's getting moved. Honestly I'm pleased. I'll make a dedicated thread for this bike in the future when I get ready to do some serious work. At least now I know I don't need to change top ends or anything, atleast not until I blow one up :evil

    [​IMG]

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    #12
  13. gsd4me

    gsd4me 90% bluff

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    [​IMG]


    [​IMG]
    #13
  14. Rucksta

    Rucksta SS Blowhard

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    It would be 25 years since RJ milled those injector bodies on a modified drill press.
    He never fails to impress me.
    I still get a buzz remembering blowing away a GPZ 900 down the Maudsland Rd.
    #14
  15. Biebs

    Biebs BMW Airhead

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    That is interesting do you have any more info on this bike??
    #15
  16. gsd4me

    gsd4me 90% bluff

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    [​IMG]


    [​IMG]


    K front end (I think), rear rim on front, wider rear rim, rear disc, heaps of little stuff. It has about 270,000Km on the clock and is very reliable; not used much these days as its owner has newer toys to use.
    #16