Carby Needed: Perfect fuel/air Mix and Revs

Discussion in '2-Stroke Engines' started by shred_cred, Nov 7, 2011.

  1. shred_cred

    shred_cred New Member

    So i've found that my "80cc" 2 stroke gets a significant "boost" when i turn the fuel line off momentarily.

    which makes me think that i could have a lot more air going into the chamber.
    Any suggestions?

  2. keatonx

    keatonx Member

    When you turn it off your engine is leaning out(too much air, not enough gas). This can cause engine damage and overheating over time, but it does give a small speed boost.
  3. motorpsycho

    motorpsycho Active Member

    yeah it's getting more air when you turn the fuel off and let the float bowl run apmost empty. this will lean out the air-fuel ratio significantly (a lot more air than fuel) and could eventually lead to a hole burned in the piston.
    every engine will make more power when the air-fuel ratio is leaned out, but the engine won't last long if you run it that way.
  4. HeadSmess

    HeadSmess Well-Known Member

    meh. havent siezed one yet from running too lean.

    ive always found if the jets too small, so too wont get it to accelerate anyway, no danger there.

    too rich, waste fuel, go slow, make smoke, no power.

    too lean, in these go at all :)

    get a smaller jet. one you get one that dies when you open the throttle, go back up a size.

    you have a very advanced and technical carb if you can lean it out so far to cause damage whilst still being able to run properly....on a ht at least.

    other way of leaning the mix slightly is to increase the oil ratio ;) good for the fine tuning. extra oil keeps things lubed up despite the extra heat. thats how i see it...