1982 Seca XJ750, ZRX1200 has company now.

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  • Bonz
    XS-XJ Super Guru
    • Apr 2008
    • 3248
    • Palmer Lake, Colorado

    #46
    Shinko 230's arrived. Goal is new float needles tomorrow, spin around the block. If all goes well with carbs sealing, wheels off and to local shop next week to get them mounted. Tire mounting is the only thing I don't do, want to give some business to my local guy. IMO, good to have a relationship with at least one motorcycle repair shop. In case you need to borrow a tool such as an impact driver for carb rack screws... Have my own now, didn't when I needed one last fall working on a first generation Vmax carb rack.
    .
    Howard

    ZRX1200
    Seca 750

    Comment

    • Bonz
      XS-XJ Super Guru
      • Apr 2008
      • 3248
      • Palmer Lake, Colorado

      #47
      It's been a minute since I posted on the Seca 750. It has been holed up for the "winter" that we never really had here in Colorado. The ZRX 1200 has gotten all riding which is a little over 2,000 miles since September given how mild the weather has been.

      Yesterday I rehabbed the stock float needles by polishing the brass bodies and using 3M label and adhesive remover on a soft cloth to clean the rubber needle tips. Spray a small amount on the cloth, spin the needle tip in the cloth with a relatively light pressure. Amazing the light layer of decomposed rubber for lack of a better term that each tip had. However the tips are all straight and true with no ring where they rest on the seat. They are decently pliable when compared to newer needle tips now that they are all cleaned up.

      I had used the 3 mm float bowl fuel level that's in the factory service manual when setting the floats previously and the closer I got to 3 mm, the more the carbs would dump fuel with the aftermarket repair kit needles. Went back to a "set it and forget it" mindset with the rehabbed stock float needles and put them at 17.5mm +/- .5mm. Did a trial run on the bench and the carbs sealed up with no issues.

      Got them back on the bike, started right up and I'm really pleased.

      Front brakes as I posted last fall are completely rebuilt and that master cylinder behind the light was the biggest pain in the butt.

      Today is going to be spent getting the wires back into the headlight housing along with the horns that mount inside of there as well. Had to remove the headlight housing and disconnect a lot of wires to get the clearance to get that master cylinder out.

      As well, I noticed yesterday number two cylinder would cut in and out, traced it easily and quickly to a plug wire connecting to the boot on the number two cylinder. Going to trim all the wires back to expose fresh wire which probably should be done anyway even if they were working fine given the age of the bike.

      Anyway, it's in the home stretch now that the carbs seem to be good.
      Last edited by Bonz; 04-12-2026, 05:52 PM.
      Howard

      ZRX1200
      Seca 750

      Comment

      • Bonz
        XS-XJ Super Guru
        • Apr 2008
        • 3248
        • Palmer Lake, Colorado

        #48
        Instead of making the above post from earlier this morning longer, I would like some thoughts:

        This morning, 40°- 45° temperature in the garage here at 7,200' in Palmer Lake. Bike started without any enrichener, almost settled into a steady idle and would take gentle throttle without a problem to steady the idle.

        I'm running one size smaller pilot jets than stock and have the screws at two turns out from seated on carbs one through three and one and a half turns on number four because it has a body from an early XJ650 apparently, those had a coarse thread pilot screw that moves further with every turn. Mains are 118 (stock 120), pilots 38 (40 stock), pilot air jets are stock at 225 and 80. Hitachi carbs used some interesting design, but seem to have had a good run of success back in the day.

        Question: Screws are in about as far as practical, go down another size on pilots? It shouldn't start that easily at that temperature without the enrichener IMO. For information, with the enrichener off, the plungers are fully seated so there's no unintended enrichening taking place.
        Last edited by Bonz; 04-12-2026, 08:49 AM.
        Howard

        ZRX1200
        Seca 750

        Comment

        • Bonz
          XS-XJ Super Guru
          • Apr 2008
          • 3248
          • Palmer Lake, Colorado

          #49
          Put the first mile on it since it was last plated in Illinois in 2007. Front brakes are marginal with respect to feel because of the remote master cylinder behind the headlight that's activated from the lever by a cable, front brake power was average at best. Rear drum brake has good feel and good modulation. Shifted fine, pulled cleanly.

          Put fuel screws at 3 turns out after playing with them a bit before the maiden voyage. Idle would stay high, sometimes it would drop back down but still higher than spec. I'll play with the idle adjustment, a synchronization will help as well. Time for a YICS tool of one type or another.

          Now it can sit proudly next to it's ZRX 1200 stable mate in the garage.
          Last edited by Bonz; 04-12-2026, 12:59 PM.
          Howard

          ZRX1200
          Seca 750

          Comment

          • cajun31
            Moderator
            • Oct 2003
            • 1936
            • Brandon, MS

            #50
            Originally posted by Bonz
            Instead of making the above post from earlier this morning longer, I would like some thoughts:

            This morning, 40°- 45° temperature in the garage here at 7,200' in Palmer Lake. Bike started without any enrichener, almost settled into a steady idle and would take gentle throttle without a problem to steady the idle.

            I'm running one size smaller pilot jets than stock and have the screws at two turns out from seated on carbs one through three and one and a half turns on number four because it has a body from an early XJ650 apparently, those had a coarse thread pilot screw that moves further with every turn. Mains are 118 (stock 120), pilots 38 (40 stock), pilot air jets are stock at 225 and 80. Hitachi carbs used some interesting design, but seem to have had a good run of success back in the day.

            Question: Screws are in about as far as practical, go down another size on pilots? It shouldn't start that easily at that temperature without the enrichener IMO. For information, with the enrichener off, the plungers are fully seated so there's no unintended enrichening taking place.
            Howard, If you think the pilot screws are turned in as far as you want then I don't see any other alternative but to go down a size on the jets. I agree with you that it should not be idling on cold starts and for sure not with the temps you described. Running way rich.
            2 - 80 LGs bought one new
            81 LH
            02 FXSTB Nighttrain
            22 FLTRK Road Glide Limited
            Jim

            Comment

            • Bonz
              XS-XJ Super Guru
              • Apr 2008
              • 3248
              • Palmer Lake, Colorado

              #51
              Thanks for responding. It's perplexing because I'm already down one size on the pilots from stock. Past experience at 7200' elevation says that usually does the trick. The Hitachi carburetors have pilot air jets, figured it would be best to lean out the pilot circuit with smaller fuel jets. Pilot air jets are opposite effect. The larger the number, the leaner the mixture. In any case I'll play with it some more and keep you all posted.
              Howard

              ZRX1200
              Seca 750

              Comment

              • Socer4m
                XStremely XSive
                • Sep 2020
                • 270
                • san diego

                #52
                Sounds like a nice little ripper getting some love,,,hope the seca keeps on going strong. If I get back from Pa end of June, hope to get out to Colorado for the annual Bonz XS rally, get together and I can bring the gauges and yics tool out..if it can wait that long..or if you are coming out to the NE rally I can bring them there,,,,,..still bummed about our fellow member Joe and Scott,,,,so, keep on restoring,,,seeya, Mike in S.Diego and Pa

                Comment

                • Bonz
                  XS-XJ Super Guru
                  • Apr 2008
                  • 3248
                  • Palmer Lake, Colorado

                  #53
                  Can you share any more about Scott/3Phase? Bob XJOK2PLAY had told me he heard it when he alerted me to Joe's daughter's Facebook about Joe's passing.

                  I'll synchronize them the standard way, it'll get it close like everybody says it will. The YICS tool would be nice if you are going to make it out. We can check it in Westcliffe. If I pick one up in the meantime I'll let you know.
                  Last edited by Bonz; 04-12-2026, 06:00 PM.
                  Howard

                  ZRX1200
                  Seca 750

                  Comment

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