Very Happy with RT carb from ThatsDax

Discussion in '2-Stroke Engines' started by Bzura, Nov 12, 2013.

  1. Bzura

    Bzura Member

    I needed a few small things for a couple of bikes I built so I decided to order from thatsdax so I could get an RT carb & save on shipping for everything. I always rode with the stock carbs that came with 66cc HT's, and I never know how much of a difference a better carb & right jet would make.

    I installed the carb on my own bike that was running very good. I port-matched the intake & exhaust as good as possible, milled tho head & top of cylinder, and removed all over-cast slop in all 4 ports & where applicable. It was running a LOT better that a plain old stock HT, but with the new carb it ran smoother, sounded better & had more torque as well as speed.

    I took the afternoon & tried different jets out. I'm not sure what the stock jet size is, but after trying them all out I could clearly see the 60 jet was the best performer. The 65 ran pretty good, but there was still a bit too much 4-stroking. With the 60 it only 4-strokes a little in high rpm's.

    The throttle response is also improved with the new carb, and there is more of a crisp feel to it now as well. I can not say enough good things about the RT. Also, Thatsdax is a class act too. Took a few days for them to even get the merchandise packed up & shipped, but it still arrived 5 days after I ordered it.

  2. jaguar

    jaguar Well-Known Member

    Anything is tons better than the stock carb which doesnt even have a separate idle mixture circuit.
  3. Waxxumus

    Waxxumus Member

    What fuel Mix are you running, and what spark plug are you using to keep it from leaning out too much. Ive got a .70 i put in mine, it gets up to only 20-24 mph, and it 2 strokes through low and mid easily, but the high end 4 strokes.
    Plug ends up rich if run low/mid for long periods.
    And the plug ends up lean if held at above 3/4th throttle for more than 5 mins or so.
    Could i theoretically put a leaner jet in? or should I put a hotter spark plug in?
  4. jaguar

    jaguar Well-Known Member

    > it 2 strokes through low and mid easily

    ?WTF, it is a 2 stroke engine!

    >but the high end 4 strokes. And the plug ends up lean if held at above 3/4th throttle for more than 5 mins or so.

    ?WTF, 4 stroking is a too rich condition but then you say the plug shows a lean condition. Can't be both.
  5. Waxxumus

    Waxxumus Member

    Thats right. It has to be leaned out to properly 2 stroke, but once it reaches the high end it appears to be too rich. If i put a .05 lower jet on the carb, it gets too lean and almost immediately turns the plug whitish.
  6. Waxxumus

    Waxxumus Member

    im running a .70 but, im not sure, maybe the plug just needs to be colder and the jet leaner