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yamaha oversized pistons

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  • yamaha oversized pistons

    anyone out there have oversized pistons for sale i need to bore and cant find pistons less than 500.00 i could care less if they are used...but in good shape
    windjammer gump
    bikes now own
    1981xs1100sh special
    1971 cb 350
    mini chopper project
    bikes use to own
    1978 750/four..
    1983kz1100 ltd

  • #2
    They are SUPER RARE. You would be better off getting a used engine if the cylinders.fees are that bad. Have you pulled the head to actually see what the cylinders look like?
    Nathan
    KD9ARL

    μολὼν λαβέ

    1978 XS1100E
    K&N Filter
    #45 pilot Jet, #137.5 Main Jet
    OEM Exhaust
    ATK Fork Brace
    LED Dash lights
    Ammeter, Oil Pressure, Oil Temp, and Volt Meters

    Green Monster Coils
    SS Brake Lines
    Vision 550 Auto Tensioner

    In any moment of decision the best thing you can do is the right thing, the next best thing is the wrong thing, and the worst thing you can do is nothing.

    Theodore Roosevelt

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    • #3
      How big ya want to go? I have a set I picked up from Crazcnuk that look huge with domes on em. Would have to measure them to see what size they are.
      2-79 XS1100 SF
      2-78 XS1100 E Best bike Ever
      80 XS 1100 SG Big bore kit but not fully running yet.
      Couple of more parts bikes of which 2 more will live!

      Comment


      • #4
        Originally posted by Rasputin View Post
        How big ya want to go? I have a set I picked up from Crazcnuk that look huge with domes on em. Would have to measure them to see what size they are.
        wasn't he the one that had the 80mm pistons?
        Nathan
        KD9ARL

        μολὼν λαβέ

        1978 XS1100E
        K&N Filter
        #45 pilot Jet, #137.5 Main Jet
        OEM Exhaust
        ATK Fork Brace
        LED Dash lights
        Ammeter, Oil Pressure, Oil Temp, and Volt Meters

        Green Monster Coils
        SS Brake Lines
        Vision 550 Auto Tensioner

        In any moment of decision the best thing you can do is the right thing, the next best thing is the wrong thing, and the worst thing you can do is nothing.

        Theodore Roosevelt

        Comment


        • #5
          Do you NEED to bore or just WANT to bore?

          If your cylinders look like they can be honed to a nice cross hatch and you are still within tolerance, say around 2.815" +/- measured in several places in the cylinder after you hone and your pistons measure around 2.813" +/- just above the skirt then you can still get a piston/cylinder wall clearance of .002" +/-. That is on the edge of the tolerance but there is probably no need to re-bore.

          Believe me, its worth checking all this our first as replacement or after market stuff for this motor is rare and quite expensive.
          Mike Giroir
          79 XS-1100 Special

          Once you un-can a can of worms, the only way to re-can them is with a bigger can.

          Comment


          • #6
            I can measure them and take some pics sometime today. I seem to remember the number 74mm, but will have to check.
            2-79 XS1100 SF
            2-78 XS1100 E Best bike Ever
            80 XS 1100 SG Big bore kit but not fully running yet.
            Couple of more parts bikes of which 2 more will live!

            Comment


            • #7
              Soooo while were on this subject. How often are people buy pistons for there bikes? I have been thinking about making a new set for my bike. Making them from 7075 and then having them cryo treated and then ceramic coated. We use to do that back in my race days with VW and porsches 10+ years ago.
              I was planning on making 74mm pistons and boring out my motor but im doing research right now on if a 1978 block has enough meat to do it. I hear rumor that the 1980 had more meat than the 78

              anyway thought i would throw that out there.
              1978 E XS1100 purchased for =$600.00
              crap load of time spent modifying it = Priceless
              My bike has the XS motor but can't really call it XS11
              (or at least it still looks like the XS motor)
              it has about 50% of the frame left from the XS bike

              Comment


              • #8
                1 top ring is missing in this set. I have no idea if they can be found. Some kind of fancy wrist pins that have buttons and floating pins. RCE 75mm cast inside. The jugs are not useable, but man are they hogged out compared to the stock one.



                2-79 XS1100 SF
                2-78 XS1100 E Best bike Ever
                80 XS 1100 SG Big bore kit but not fully running yet.
                Couple of more parts bikes of which 2 more will live!

                Comment


                • #9
                  wiseco kit being installed

                  went ahead an found a 1179 kit and just bought new stuff ....pistons are rare so if anyone has any they better hold on to them
                  windjammer gump
                  bikes now own
                  1981xs1100sh special
                  1971 cb 350
                  mini chopper project
                  bikes use to own
                  1978 750/four..
                  1983kz1100 ltd

                  Comment


                  • #10
                    I have the 80mm pistons...no rings or wrist pins. Brand new. Racing pistons, forged Alcoa aluminum. 11:1 compression ratio. Venolia brand, they are still in business. $50.00 + shipping if you are interested.

                    Stock bore for an XJ is 71.5mm (stroke is 68mm) These forged pistons are 79.325 mm by means of a friend's dial caliper, meaning they would - probably - fit an 80mm bore. Would make the XS engine out to be about 1232CCs.
                    Jerry Fields
                    '82 XJ 'Sojourn'
                    '06 Concours
                    My Galleries Page.
                    My Blog Page.
                    "... life is just a honky-tonk show." Cherry Poppin' Daddy Strut

                    Comment


                    • #11
                      Hey Jerry. My Yamaha manual says the stroke on the XS is 68.6mm. Now I dont know if the XJ is any different but I ran the numbers on a displacement calculator for yours and wow!

                      Bowling's Engine Displacement Calculator
                      Input Parameters Are the Following:

                      Number of Cylinders are = 4 to 1
                      Piston Diameter = 80.000 Millimeters
                      Piston Oversize = 0.000 Millimeters
                      Engine Stroke = 68.600 Millimeters

                      Computation Results:
                      Computed Engine Displacement (CID) is 84
                      Computed Engine Displacement (Litres) is 1.4
                      Computed Engine Displacement (CC) is 1379.3
                      2-79 XS1100 SF
                      2-78 XS1100 E Best bike Ever
                      80 XS 1100 SG Big bore kit but not fully running yet.
                      Couple of more parts bikes of which 2 more will live!

                      Comment

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