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400 to 650 motor swap

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    400 to 650 motor swap

    I'm going to look at a 650 motor and carb to swap into my currently 400 Bros.

    What should I be looking out for? What questions should I be asking?

    Also it was told to me a while ago here on the forum that the CDI doesn't need to be changed. Is there anything else I will need for the swap?


    #2
    The 400 has a speed chip in the speedo, and I believe that needs to see that handshake from the chip and CDI ... ( I think ) possibly using both would still read the same but then you have that speed function screwing with the top speed ? I really dont know the details of what or how it works , only that it exists.

    There is a thread about this PCB, and some vague you can bypass it guessing somewhere as well.

    I guess using Hawk or aftermarket clocks and Hawk CDI would skirt around it. Although ...check that, some racer guys use the 400 CDI because it has a higher rev limiter. There maybe a slight difference in the 400 harness speedo to CDI ( COMMUNICATION wire/s from the speed PCB) ?

    Anyway, that's the info I'd be looking for. Obviously we don't have any 400's in the States so the guys that have done this are in Japan and Europe for the most part.

    I've always been interested in both the 400's speedo chip and the later ignition system changes on the Bros

    We do have some Japanese Factory Bros manuals in PDF format , you have to hunt the files twords the end to find the wiring diagrams , unfortunately they're in black and white which just makes things that much tougher to read.
    Last edited by SPA; 03-16-2019, 10:43 PM.
    "Hawk Porn" http://picasaweb.google.com/11124379...eat=directlink 1990 NT650-Penske 8981, Race-tech Springs & Gold Valves, Steve Lenac six-piston caliper & EBC rotor,SS Brake lines Ft / Rear lines through SSA ,VFR brake lever, F2 front wheel, F-120/70 R-160/60 Dunlop Roadsmart, Full-Supertrapp Exhaust, Stage 1 Jet kit, K&N Filter, Corbin Seat, Pro-Tec Clip-On's/ Past Rides...1986 VFR700F2 Interceptor / 1979 Yamaha Rd400 Daytona Special

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      #3
      BBBROS our member from the Land of Rising Sun may have information ? ( 400 to 650 motor swap , what's needed ? )

      Quite a few members with 400's in Ireland , and I believe this topic has come up a few times here over the years
      "Hawk Porn" http://picasaweb.google.com/11124379...eat=directlink 1990 NT650-Penske 8981, Race-tech Springs & Gold Valves, Steve Lenac six-piston caliper & EBC rotor,SS Brake lines Ft / Rear lines through SSA ,VFR brake lever, F2 front wheel, F-120/70 R-160/60 Dunlop Roadsmart, Full-Supertrapp Exhaust, Stage 1 Jet kit, K&N Filter, Corbin Seat, Pro-Tec Clip-On's/ Past Rides...1986 VFR700F2 Interceptor / 1979 Yamaha Rd400 Daytona Special

      Comment


        #4
        Originally Posted by SPA View Post
        The 400 has a speed chip in the speedo, and I believe that needs to see that handshake from the chip and CDI ... ( I think ) possibly using both would still read the same but then you have that speed function screwing with the top speed ? I really dont know the details of what or how it works , only that it exists.

        There is a thread about this PCB, and some vague you can bypass it guessing somewhere as well.

        I guess using Hawk or aftermarket clocks and Hawk CDI would skirt around it. Although ...check that, some racer guys use the 400 CDI because it has a higher rev limiter. There maybe a slight difference in the 400 harness speedo to CDI ( COMMUNICATION wire/s from the speed PCB) ?

        Anyway, that's the info I'd be looking for. Obviously we don't have any 400's in the States so the guys that have done this are in Japan and Europe for the most part.

        I've always been interested in both the 400's speedo chip and the later ignition system changes on the Bros

        We do have some Japanese Factory Bros manuals in PDF format , you have to hunt the files twords the end to find the wiring diagrams , unfortunately they're in black and white which just makes things that much tougher to read.

        Hello,

        This is my personal view of BROS in Japanese specification.

        First, we can think of engines of J model and K model as the same model.
        There is no problem to think that 400 and 650 are the same.

        L-model(mark II) is different and difficult to obtain.
        If you want challenge, you can also use it as a J / K-model by changing the pickup unit of the pulse generator in the engine.

        Next, please know the model of the igniter unit to use.
        J model is 8 wires, K model is 9 wires.
        The same is true for speedometers.

        Although they are compatible with each other, please be careful when using the K-model igniter unit.

        K-model's igniter unit and speedometer unit have green / white wires that J-model does not have.

        The watchdog in the igniter unit watches the voltage of the green / white wire.

        Ignition is reduced if no voltage is applied to the green / white wire of the igniter unit by removing the meter or using a J model meter.

        In that case, you can connect the green / white and brown / black wires and fool the watchdog.

        Comment


          #5
          BBBROS Thanks so much for your response and the "Japanese Connection" inside information on Bros motor swaps !!! Awesome !!!

          TimCthefilmguy looks like we've found your Huckleberry. I'll bet more questions come up, please keep us here on the forum up to date with your project and knowledge database.

          363d4f535512ec5a0589e747140a8aa8.jpg
          "Hawk Porn" http://picasaweb.google.com/11124379...eat=directlink 1990 NT650-Penske 8981, Race-tech Springs & Gold Valves, Steve Lenac six-piston caliper & EBC rotor,SS Brake lines Ft / Rear lines through SSA ,VFR brake lever, F2 front wheel, F-120/70 R-160/60 Dunlop Roadsmart, Full-Supertrapp Exhaust, Stage 1 Jet kit, K&N Filter, Corbin Seat, Pro-Tec Clip-On's/ Past Rides...1986 VFR700F2 Interceptor / 1979 Yamaha Rd400 Daytona Special

          Comment


            #6
            Thanks for all the info. Turns out the donor bike's registration had lapsed and the owner who it was registered to had left the country. So with no way to transfer registration it would have made my bike illegal. Looks like I'll be sticking with my 400 for now but keeping my eyes open for another 650

            Comment


              #7
              I did the swap few years ago. all you need is 650 motor and carbs, everything else can be used from 400.

              Comment


                #8
                Originally Posted by toxa View Post
                I did the swap few years ago. all you need is 650 motor and carbs, everything else can be used from 400.
                Cool thanks !
                "Hawk Porn" http://picasaweb.google.com/11124379...eat=directlink 1990 NT650-Penske 8981, Race-tech Springs & Gold Valves, Steve Lenac six-piston caliper & EBC rotor,SS Brake lines Ft / Rear lines through SSA ,VFR brake lever, F2 front wheel, F-120/70 R-160/60 Dunlop Roadsmart, Full-Supertrapp Exhaust, Stage 1 Jet kit, K&N Filter, Corbin Seat, Pro-Tec Clip-On's/ Past Rides...1986 VFR700F2 Interceptor / 1979 Yamaha Rd400 Daytona Special

                Comment

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