Is the carb the problem

Discussion in '2-Stroke Engines' started by mbatl, May 23, 2009.

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  1. mbatl

    mbatl Guest

    This 80cc has never ran correctly, after drilling out the jet, using cardboard to fix an airleak, and adjusting the rich/lean mixture it still doesn't run correctly. It basically shakes badly like it is not burning smoothly. It runs the best of all right now on the leanest setting, which is probably because drilling the jet made it run richer. Could it be a faulty carb? What are the symptoms of a bad cdi? bad coil?

    Also, how do you make/get a new coil wire w/o buying it directly? Thanks.

  2. Skyliner70cc

    Skyliner70cc Active Member

    Odds are if it fires up, its not the cdi or coil. I would chuck the cardboard and use real gasket material available from Napa autoparts and then coat both sides of the cut gasket with gasket tack to seal it up.

    I would return to stock settings which work quite well on the jet setting even though the low end is typically a little richer than I prefer. Another great way to awaken an engine and remedy the stock rich setting on the low end is to purchase a slant head which is a high compression head. This head really brings out the best in the stock carb.
  3. mbatl

    mbatl Guest

    Ok, I ordered a new carb so I can start fresh with stock settings and jet size.
  4. Mountainman

    Mountainman Active Member

    new carb -- starting fresh -- it's a GOOD THING

    that's the move that I was going to suggest

    drilling out the jet -- especially early in the game -- may not be a good THING

    bought an old one lunger BSA 250cc years ago
    THING just didn't run right
    took the carb apart noted jet size
    repair shop said that someone had changed it from orig to larger
    I bought the orig and put it in -- that's the one that was made for it !!

    good luck with the new carb -- from - MM
  5. Pablo

    Pablo Motored Bikes Sponsor

    Stock jet size is too large to begin with. As you probably know by now, you went the wrong way and made it worse. I suggest .65mm as a starting point.
  6. mbatl

    mbatl Guest

    Thanks, the carb will allow me to interchange parts as well. I'm just ready to get back to riding, its still in the break-in period. The best part so far is running a little figure 8 type circuit including leaning turns and WOT!