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Thread: Valve setting 100cs 1981

  1. #1
    Registered User blackbeauty's Avatar
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    Valve setting 100cs 1981

    100cs 1981. Valve settings?
    Doing my 30k all fluid service and preparing to set intake & exhaust clearance. I've got a new Clymer (10&20mm) and a real old Clymer (15&20mm) along with the original booklet that indicates after break in (10 & 15mm). I'm thinking of following the old booklet with intake of 10 and exhaust of 15mm. Why all the in consistency from one edition of the same book and then the factory booklet? Is there any advantages to one of these setting over the other?

    Thanks,
    Herb

  2. #2
    NORTHCOUNTRY
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    Herb; I'd go with new Clymer due to the gas we have to use. Also my 1977 100/7 runs a little cooler with intake at 15. Can't really say why but after the first 150,000 miles I'm not gonna change it.
    Also Have to admit to owning a Oil Head Rt and like the comfort for 2 up but there is nothing better than an airhead when out on the road alone.

  3. #3
    NORTHCOUNTRY
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    Herb; Sorry.... should have said 'Old Clymer.' I'd go 15 intake and 20 exhaust. Been doing it since 1978 on my 100/7.

  4. #4
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    ticky valves are happy valves. use the 15/20 setting.
    Ride Safe, Ride Lots

  5. #5
    Total Freak mikegates's Avatar
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    loud vales save lives
    95 R100Rt, 07 650 GS
    Mike
    Eagle, wi
    "He's gone and nothin gone bring him back"

  6. #6
    Bluenoser
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    Quote Originally Posted by oldbeemer View Post
    Herb; Sorry.... should have said 'Old Clymer.' I'd go 15 intake and 20 exhaust. Been doing it since 1978 on my 100/7.
    This is what my R75/6 owners manual recommends. 6 & 8 Thous or 15 & 20 mm, whichever suits your fancy. Most of us in this neck of the woods use these gaps for the valves.
    1971 R50/5 SWB with R75/6 drivetrain
    2013 DL650

  7. #7
    Registered User lmo1131's Avatar
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    mmm mmm .... 20mm is almost an INCH.

    Methinks you're referring to .15mm (.006") and .20mm (.008")

    +1 on Noisy valves save lives!
    "It is what you discover, after you know it all, that counts." _ John Wooden

    Lew Morris
    1973 R75/5 - original owner

  8. #8
    Benchwrenching PGlaves's Avatar
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    Quote Originally Posted by Lmo1131 View Post
    mmm mmm .... 20mm is almost an INCH.

    Methinks you're referring to .15mm (.006") and .20mm (.008")

    +1 on Noisy valves save lives!
    BMW changed the spec at least twice.

    Early airheads were specified at .10mm (.004") and .15mm (.006")

    Later airheads were then specified at .15mm (.006") and .20mm (.008")

    Later the latter specification .15mm (.006") and .20mm (.008") was back applied to the earlier bikes.

    When Oak Okleshen rebuilt a set of heads for me he advised .006" intakes and .010" exhausts for the first several thousand miles - then .006" and .008" would be OK.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://www.bigbend.net/users/glaves

  9. #9
    Registered User blackbeauty's Avatar
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    Intake & exhaust settings

    Guys,

    Thanks for all the feedback and sharing the expertise. I'm going with the .15mm intake & .20mm exhaust settings as most suggest.

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