Carby Small hole--- big difference

Discussion in '2-Stroke Engines' started by Dakman, Aug 24, 2011.

  1. Dakman

    Dakman New Member

    I've as a last resort done the solder the jet and redrill thing, I wish I'd have done this a lot sooner as the improvement in smoothness and a much greater top speed is startling. I've been chasing every other possible cause for a lousy performing bike and just wasn't sold on the idea that such a small difference in diameter of the jet could solve the problems I was having.

    If anyone is in two minds like I was then just give it a go, hopefully it could be just what your bike needs.

    In a long list of negative experiences with this bike I'm quite happy with it at the moment.

  2. HeadSmess

    HeadSmess Well-Known Member


    i gotta say something here... dont go too small! the difference then is major and dramatic! she wont run! :D

    ok, actually, what i meant to say was...drilling jets apparently isnt the ideal way to go.
    ive always drilled them myself, but upon some research the other night, i found something id never known before!

    jets arent labelled by the size hole through them until you get up to really big 1.5mm etc...

    standard size jets are labelled on flow! L/m, or Gal/hr. exactly what flow and what figure varies between manufacturer.

    it makes sense. a .5mm hole thats only 2mm long will flow a lot more than a .5mm hole that is 5mm long! not all jets are made at the same time, so these variations can and do occur!

    so, all i can say is, when soldering jets...get as LITTLE solder in there as possible! or dress the excess off with a drill bit... as the length of hole is just as important as diameter! yes, i have a .65 that runs LEANER than a .55, as drilled by me :D i did scratch my head a while over that one...

    i use the "wire in the jet" trick now :D just drill em big and keep inserting fine strands of wire til theyre good!
  3. 2strokepoke

    2strokepoke Member

    isn't there a place where you can purchase jets?
  4. dodge dude94

    dodge dude94 Member

    I know you can get them at SBP, and I did see them at pirate, but now I can't find them....
  5. motorpsycho

    motorpsycho Active Member

    yes, a TINY change in the jet size will make a huge difference.
    part of the problem is that people usually go too small with the hole, lean it out and burn up a piston.
    when going from rich to lean it's best to make very small hole size changes in steps until you get it right.
  6. motorpsycho

    motorpsycho Active Member

    yes, sbp sells dellorto jets.
  7. happycheapskate

    happycheapskate Active Member

    Changing spark plugs seems to make a large difference (for better or worse!)