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Need to put Allen Cap Heads on Air Mixtuure Screws...

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  • Need to put Allen Cap Heads on Air Mixtuure Screws...

    I'm not sure whether to braze or use silver solder.

    If I braze - should I use a high silver content rod?

    I have 4-40 brass screws that I will be cutting the heads off of to attach to the air mixture screws on some non-standard carbs for a Yamaha RD350 w/PWK carbs on and RD400 engine/tranny.

    This will make adjusting the mixture a bit easier because you just don't have room for a screwdriver...

    Any suggestions?



  • #2
    If the screws and heads are brass I would use lead free solder. Flux it and solder it right up. It takes less heat to solder than to braze. Less apt to mess up your screws..


    • #3
      I made a couple sets up for some AHRMA racers a few years back blus float bowl quick release screws that were tool less for quick, in the pit jet changes.

      The float bowl screws were 18-8 metric stainless studs, 272 threadlocked in aluminum hex stock, turned down with the hex left proud so they could do finger jet changes. I deformed the first few threads on the studs to insure a locked condition.

      I drilled the slotted end of the mixture screws and used a 4-40 bottoming tap and threaded into the meat of the screw. I then threadlocked a short 18-8 stainless stud (just like the floatbowl screws) and attached a knurled knob (threaded to attach to the stud) and threadlocked it as well.

      I made about 10 sets for the racers. They were running Mikuni smooth bore race carbs. TDK's I believe.

      That is the easiest way to obtain finger adjustable jetting. It looks good plus it is vibration proof and straight. You'll heva e a really hard time getting a socket head attached to the screw, especially getting them straight.....

      They had no problems and were very happy with the result. When my customers are happy, so am I.
      So little time...So many machine tools.........

      Miller, Hobart & Lincoln TIG/MIG/-
      Hypertherm Plasma (Thanks Jim)
      Plasma-Cam DHC (coming shortly)
      Harris OA
      Too many motorcycles.............-


      • #4
        Need to put Allen Cap Heads on Air Mixtuure Screws

        Just a quick update. I have a CAD drawing of the 350/250 heads. I will post as soon as I can find a way to do from a PDF file.