Lectron or smart carb for Honda rs125 nx4

Discussion in '2-Stroke Machines' started by Supermotoguy, Jan 10, 2020.

  1. Supermotoguy

    Supermotoguy Member


    Only interested in hearing with those that have experience with this. New to gp bikes and road racing. Was wondering if anyone’s tried a lectron carb for the rs125 or tz. My shop says it is definitely worth it but would like to check with some of you folks. My idea of a good time does not include messing with a carburetor at a race track. Thanks.
  2. TZRusty

    TZRusty Well-Known Member

    You would want to try a 38hv with 5-1. or 5-2 needle 65 pj to start.
  3. Kurlon

    Kurlon Well-Known Member

    I don't remember the year of RS125 but my billet 38mm SC wouldn't fit on my friend's bike, the float bowl fouled the cases. Even bought the float bowl without a drain and it was a no go.
  4. TZRusty

    TZRusty Well-Known Member

    Lectrons are smaller in physical size than a Keihn. It should have no robes fitting.
  5. monkeyfist

    monkeyfist Active Member

    Not sure if this is pertinent but on my '96 RS125, I couldn't find a stock carb so after a bit of research, I ended up running a Keihin 38 PWK from one of the later KX-250s; it fit nicely into the stock boot & didn't foul the cases. And with the right connectors, it plugged right into the stock TPS and PJ wire harness connectors. It ran quite well and I found that the jetting ended up pretty close to the recommended values for the stock PJ/TPS carb.

    On that note, my bike originally had the earlier non-PJ/TPS wire harness but if you have the later ECU, you can get some connectors and wire up the TPS and PJ parts of the wire harness to the ECU plug. See https://www.usgpru.net/forum/viewtopic.php?f=5&t=12024
  6. TZRusty

    TZRusty Well-Known Member

    The 38PWK. Is the carb of choice on Honda CR125 shifter karts. I'm not familiar with th electrics of the RS125's
  7. monkeyfist

    monkeyfist Active Member

    Yep, that's the one. Interestingly, Keihin appeared to offer the OEM 38PWK in two lengths (one has a longer body than the other, I don't remember which bikes had which variants other than the later model KX-250s had the short body; some google searching was how I figured out which model was on which bikes) and there appeared to be some variation as to which OEM models had TPS, which ones had PJ, and which ones had TPS+PJ.

    In addition, Keihin also sells the aftermarket 38PWK Air Striker (if I remember the name correctly), which appeared to be a non-PJ/TPS variant of the same carb. I never looked into the Air Striker version because I was looking for the PJ/TPS version but it might also work.

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