stock petcock

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  • CaptonZap
    XS-XJ Guru
    • Jun 2010
    • 1748
    • Denver

    #16
    Howdy,

    Here is my take on this situation.
    If you got rid of the original bolts, you have problems.
    As Skids pointed out, the washer head bolts provided a sealing surface from the underside of the bolt head to the surface of the petcock around the bolt hole. Which is to say that a fiber washer between the two surfaces sealed off any gas seepage through the joint.
    Unfortunately, an Allen head does not have anywhere near the same area under the head as did the original bolts. So a fiber washer is not going to work, unless you can solder a washer to the bolt, thus making a replacement for what was there. The solder would seal the gap between the shank and the washer, and the washer would provide the sealing surface for the gasket washer between it and the petcock.
    Another solution would be to get a 45 deg countersink cutter and countersink the bolt holes in the petcock such that a thick O-ring would be compressed under the washer on the Allen bolt, and make the seal between the shank of the bolt and the petcock flange. That would require some pretty specific machining, and is not advised from this side.
    A better solution would be to Bing someplace like this place,

    and buy something that would be a hex head replacement for the originals. The 16mm length mightbe about right.

    Good luck, CZ

    Comment

    • conquest87tsi
      Truly XSive
      • Jun 2012
      • 190
      • Jackson, Minn.

      #17
      CZ, I understand your concern. However, I have some rounded head allen bolts as well as cap. The round head have the same area as a philips. The bolts I have are 16mm length, which is longer than the originals.
      1979 XS1100 SF
      1979 XS750 SF

      Previous Rides:
      1981 KZ650CSR
      2006 VTX 1300C
      1986 Radian 600

      Comment

      • Petersg_99
        Truly XSive
        • Apr 2012
        • 184
        • Phoenix, AZ.

        #18
        I got rubberized washers at Ace hardware and tried to install the petcock with regular bolts, one held, but the other didn't. I ended up going back to Ace and buying flanged bolts to get the additional sealing surface. They've worked fine for the last month or so...

        The large round O-ring is for sealing between the tank and the petcock.



        Originally posted by conquest87tsi
        CZ, I understand your concern. However, I have some rounded head allen bolts as well as cap. The round head have the same area as a philips. The bolts I have are 16mm length, which is longer than the originals.
        Guy

        1980 XS1100G - Frankenstein - resurrected from the impound lot
        1991 Suzuki GS500E (not running yet)
        2003 Burgman AN400 - Blue Belle
        2005 Burgman AN400 - Silver Belle

        Comment

        • CaptonZap
          XS-XJ Guru
          • Jun 2010
          • 1748
          • Denver

          #19
          Originally posted by conquest87tsi
          CZ, I understand your concern. However, I have some rounded head allen bolts as well as cap. The round head have the same area as a philips. The bolts I have are 16mm length, which is longer than the originals.
          Great, then the fiber washers, or ones punched out of neoprene sheet would work just fine. I coat both sides of the gasket with Gasgacinch gasket sealer. Belt and suspenders kind of guy.
          The holes go all the way throught the tank flange, so as long as the bolts have threads all the way to within an eighth of an inch of the head, you should not have any problems with the 16mm bolts.

          CZ

          Comment

          • conquest87tsi
            Truly XSive
            • Jun 2012
            • 190
            • Jackson, Minn.

            #20
            Feel like I may be stealing a thread, but what the hell. better than starting a new one right? So I stopped at Ace during lunch and got some washers. Only thing is I didn't like the gap between the fiber washers and the bolt threads so I got rubber washers instead. Now I get to see if they hold up to fuel.
            1979 XS1100 SF
            1979 XS750 SF

            Previous Rides:
            1981 KZ650CSR
            2006 VTX 1300C
            1986 Radian 600

            Comment

            • XS1100_OEM4ME
              XS-XJ Guru
              • Mar 2009
              • 1619
              • Fort Myers, Florida

              #21
              Fiber

              Originally posted by conquest87tsi
              Feel like I may be stealing a thread, but what the hell. better than starting a new one right? So I stopped at Ace during lunch and got some washers. Only thing is I didn't like the gap between the fiber washers and the bolt threads so I got rubber washers instead. Now I get to see if they hold up to fuel.
              The reason Yamaha used fiber instead of rubber IMHO, is so you can compress the "O" ring gasket between the tank and petcock to seal it tight. The rubber may work fine if it is tough enough
              1979 XS1100 Special (Mad Max, OEM) Current
              1980 XS1100 Special
              1990 V Max
              1982 KZ750 LTD Twin
              1986 700 FZR Yamaha Fazer (faster then expected)
              1979 XS750 Special (my 1st Special)
              1974 CB750-Four



              Past/pres Car's
              1961 Catalina 389/1970 Torino GT 351/1967GTO 12to1 comp./ Roller cam/ T-10/ 456 gear/Tri-power/1967 GTO 400, 1969 Camaro, 1968 Z28, 2001 BMW M Roadster 0 to 60 in 4.5 sec. Jaguar XK8

              Comment

              • crazy steve
                XS-XJ Guru MODERATOR
                • Jan 2009
                • 7932
                • Beautiful outer Yelm, WA

                #22
                Originally posted by conquest87tsi
                ...so I got rubber washers instead.
                The problem with rubber is those screws need to be tight; I suspect you'll find the washers will squeeze out before you get a leak-proof seal.

                Hard nylon washers will work too...
                Fast, Cheap, Reliable... Pick any two

                '78E original owner - resto project
                '78E ???? owner - Modder project FJ forks, 4-piston calipers F/R, 160/80-16 rear tire
                '82 XJ rebuild project
                '80SG restified, red SOLD
                '79F parts...
                '81H more parts...

                Other current bikes:
                '93 XL1200 Anniversary Sportster 85RWHP
                '86 XL883/1200 Chopper
                '82 XL1000 w/1450cc Buell, Baker 6-speed, in-progress project
                Cage: '13 Mustang GT/CS with a few 'custom' touches
                Yep, can't leave nuthin' alone...

                Comment

                • conquest87tsi
                  Truly XSive
                  • Jun 2012
                  • 190
                  • Jackson, Minn.

                  #23
                  I looked at the nylon and fiber washers but felt like they weren't even close to tight enough on the threads of the bolt. I definetly hear what your saying about the rubber washers just smooshing. Maybe I'll check out the fiber again. I'm thinking a rubber, fiber/nylon combo might work. Bolt would spin on the washer and not turn the rubber seal so much.
                  1979 XS1100 SF
                  1979 XS750 SF

                  Previous Rides:
                  1981 KZ650CSR
                  2006 VTX 1300C
                  1986 Radian 600

                  Comment

                  • XS1100_OEM4ME
                    XS-XJ Guru
                    • Mar 2009
                    • 1619
                    • Fort Myers, Florida

                    #24
                    Fuel

                    here are a few hundred to pick from



                    1979 XS1100 Special (Mad Max, OEM) Current
                    1980 XS1100 Special
                    1990 V Max
                    1982 KZ750 LTD Twin
                    1986 700 FZR Yamaha Fazer (faster then expected)
                    1979 XS750 Special (my 1st Special)
                    1974 CB750-Four



                    Past/pres Car's
                    1961 Catalina 389/1970 Torino GT 351/1967GTO 12to1 comp./ Roller cam/ T-10/ 456 gear/Tri-power/1967 GTO 400, 1969 Camaro, 1968 Z28, 2001 BMW M Roadster 0 to 60 in 4.5 sec. Jaguar XK8

                    Comment

                    • bikerphil
                      Master of XSology
                      • Jan 2008
                      • 8628
                      • South Flori-DUH

                      #25
                      MikesXS has the correct bolts and fiber washers for a buck or two, scroll down...

                      http://www.mikesxs.net/products-34.html#products
                      2H7 (79) owned since '89
                      3H3 owned since '06

                      "If it ain't broke, modify it"

                      Comment

                      • XS1100_OEM4ME
                        XS-XJ Guru
                        • Mar 2009
                        • 1619
                        • Fort Myers, Florida

                        #26
                        +1

                        Originally posted by bikerphil
                        MikesXS has the correct bolts and fiber washers for a buck or two, scroll down...

                        http://www.mikesxs.net/products-34.html#products
                        Phil is the man
                        1979 XS1100 Special (Mad Max, OEM) Current
                        1980 XS1100 Special
                        1990 V Max
                        1982 KZ750 LTD Twin
                        1986 700 FZR Yamaha Fazer (faster then expected)
                        1979 XS750 Special (my 1st Special)
                        1974 CB750-Four



                        Past/pres Car's
                        1961 Catalina 389/1970 Torino GT 351/1967GTO 12to1 comp./ Roller cam/ T-10/ 456 gear/Tri-power/1967 GTO 400, 1969 Camaro, 1968 Z28, 2001 BMW M Roadster 0 to 60 in 4.5 sec. Jaguar XK8

                        Comment

                        • CaptonZap
                          XS-XJ Guru
                          • Jun 2010
                          • 1748
                          • Denver

                          #27
                          Originally posted by conquest87tsi
                          I looked at the nylon and fiber washers but felt like they weren't even close to tight enough on the threads of the bolt. I definetly hear what your saying about the rubber washers just smooshing. Maybe I'll check out the fiber again. I'm thinking a rubber, fiber/nylon combo might work. Bolt would spin on the washer and not turn the rubber seal so much.
                          I think you are over thinking this washer thing.
                          It, the washer, doesn't have to be a tight fit on the threads for the assembly to seal. What happens is that the washer seals against the flat area on the bottom of the bolt head, which holds the washer against the flat portion on the petcock base, which presses the base against the o-ring, which seals against the tank. All of the surfaces are flat, and can benefit from a dose of gasket cement.
                          The threads don't have to seal.
                          CZ

                          Comment

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