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O-ring sizes, as promised.

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    O-ring sizes, as promised.

    First, the intakes. These are ALWAYS Viton. Anything else will burn.

    These are known as 'dash' sizes, an AS-568 sizing scheme. It does keep things simple...

    28mm = -122 aka 'Dash 122'. And so on.
    30mm = -123
    32mm = -125
    38mm = -128
    40mm = -130

    Metric sizes: Are specified by INNER DIAMETER by CROSS SECTION. You'll find them listed the other way around. To avoid confusion, we won't do that here.

    All O-rings from here on are Buna, a pretty common and useful material, and a hardness of 70 (Durometer).

    For the CV carbs:

    Interconnecting fuel tubes use the 'Dash 10' or -010.
    Choke assembly uses 10mm x 1.5mm
    CV bleed screw (the tiny one) uses 2.5mm x 1.2mm
    CV inlet uses 'dash 903'. This category of AS568 is known as a 'boss'; that might help.

    For the VM carbs, I'll add my diagram at the end because I name them A through F. This image is hosted on my website, which will be SHUT DOWN SOON, so download this image!!

    VM 'A' use 2.8mm x 1.6mm.
    VM 'B' use 3.8mm x 1.25mm.
    VM 'C' use Dash 9 (-009).
    VM 'D' use 5.1mm x 1.6mm. This is the drain screw o-ring that also fits the CV carbs.
    VM 'E' use 8.5mm x 1.5mm.
    VM 'F' use Dash 11 (-011)

    part2.jpg


    Happy hunting.

    RB
    and God said, "Let there be air compressors!"
    __________________________________________________ ______________________
    2009 Suzuki DL650 V-Strom, 2004 HondaPotamus sigpic Git'cha O-ring Kits Here!

    #2
    Saved in my documents. Thanks Robert
    MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
    1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

    NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


    I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

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      #3
      Thanks much.
      1982 GS1100E V&H "SS" exhaust, APE pods, 1150 oil cooler, 140 speedo, 99.3 rear wheel HP, black engine, '83 red

      2016 XL883L sigpic Two-tone blue and white. Almost 42 hp! Status: destroyed, now owned by the insurance company. The hole in my memory starts an hour before the accident and ends 24 hours after.

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        #4
        Thank you Robert.
        Larry

        '79 GS 1000E
        '93 Honda ST 1100 SOLD-- now residing in Arizona.
        '18 Triumph Tiger 800 (gone too soon)
        '19 Triumph Tiger 800 Christmas 2018 to me from me.
        '01 BMW R1100RL project purchased from a friend.

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          #5
          Thank you for this!
          1981 Suzuki GS650G

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            #6
            You're a good man Robert! Hope you're doing as well or better than can be expected
            1980 GS1000G - Sold
            1978 GS1000E - Finished!
            1980 GS550E - Fixed & given to a friend
            1983 GS750ES Special - Sold
            2009 KLR 650 - Sold - gone to TX!
            1982 GS1100G - Rebuilt and finished. - Sold
            2009 TE610 - Dual Sporting around dreaming of Dakar.....

            www.parasiticsanalytics.com

            TWINPOT BRAKE UPGRADE LINKY: http://www.thegsresources.com/_forum...e-on-78-Skunk/

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              #7
              Thank you Robert! Prayers for a speedy recovery
              - 1983 GS850L ~ 30,000 miles and going up - Finally ready for a proper road trip!
              - 1977 GS750B - Sold but not forgotten

              Comment


                #8
                Originally posted by 93Bandit View Post
                Thank you Robert! Prayers for a speedy recovery
                Thanks for the info sheet and thanks Robert. Will print this off and keep it handy
                Jonesz

                1979 GS850 current project
                1978 GL1000-naked
                1983 GL1100-Aspencade stripped
                1999 Valkyrie Tourer-long ride bike

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                  #9
                  Thumbs up. Cheers robertbarr
                  82 GS650E (Canadian), 83 XS650SK (Canadian), Main machines Running
                  Aussie, 74 TX650A, 80 XS650SG, 81XS650SH, 80XS850, in various states of repair/disrepair
                  Introduction and ongoing thread for myGS650Ez
                  Albums

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                    #10
                    Interesting how some ended up with "dash" sizes. Measuring, especially for smaller o-rings, is a maddening process because there are important differences between nominal and actual sizes, as well as manufacturing tolerances.

                    Plus, there are many oddball metric sizes that were used but not actually a standard manufactured size. The whole thing takes a lot of patience, conversion, and experimentation; sometimes o-rings that should work on paper don't have quite the correct fit in reality.

                    I found the same dash sizes for intakes years ago, when metric Viton o-rings in these sizes were unobtainable. They're actually very slightly "fatter" in cross-section than the OEM intake o-rings, which I think slightly improves the sealing. Viton is also a fair bit harder than the OEM o-rings, but that doesn't seem to matter much, and Viton intake o-rings work perfectly. I've had them in place on my bike and many others for a long time, and they were pretty inexpensive in bags of 25 from McMaster-Carr.

                    As Robert states, Buna-N is the correct material for the carb o-rings. Viton is a bit harder, and that makes a difference in many places, especially sealing around threaded jets and needle adjusters.

                    Robert, many thanks for your hard work and for sharing the data!
                    1983 GS850G, Cosmos Blue.
                    2005 KLR685, Aztec Pink - Turd II.3, the ReReReTurdening
                    2015 Yamaha FJ-09, Magma Red Power Corrupts...
                    Eat more venison.

                    Please provide details. The GSR Hive Mind is nearly omniscient, but not yet clairvoyant.

                    Celeriter equita, converteque saepe.

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                    Get "The Riding Obsession" sport-touring motorcycling podcast at https://tro.bike/podcast/ or wherever you listen to podcasts!

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                      #11
                      Well now I feel bad that I don't check the forums nearly as often as I should. I hear about these things way too late.

                      Best wishes for a speedy recovery, Robert. And thank you for sharing your knowledge. Yet another reason why I love this community.
                      Charles
                      --
                      1979 Suzuki GS850G

                      Read BassCliff's GSR Greeting and Mega-Welcome!

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