Engine Trouble Exhaust is spitting gas

Discussion in '2-Stroke Engines' started by dunne, May 16, 2015.

  1. dunne

    dunne New Member

    I've got a Chinese 66cc and have just upgraded to dax's racing carb and a wrap-around voodoo expansion exhaust. My bike sounds as though its turning over but no acceleration so matter how far I open up the throttle. Pulled off the expansion chamber and a bunch of gas was in the pipe. Figured it might be a spark plug issue or mix was too rich, so I replaced the stock plug with NGK b6hs and tried to do the kill switch test for the fuel-air mix, but the plug wasnt discolored at all, looked brand new. I disconnected the kill switch and still nothing. Did I blow out the cdi? Any suggestions?
     

  2. dunne

    dunne New Member

    I've also just switched out for a 36 tooth sprocket with clamshell adapter and #41 chain, but figured these details don't mean much
     
  3. Slogger

    Slogger Member

    I don't know much about bikes with expansion chamber pipes, but if a bunch of liquid gas was in there I'd take a look at the carb float needle and seat, to make sure it isn't flooding. The stuck open needle would cause your engine to run so rich it won't really pull at all.
    Clean it up good, any grit in there and it won't close. Check the float also, if it is 'wet' (leaking gas into itself) it will flood the engine.
    Hope this helps.
     
  4. crassius

    crassius Well-Known Member

    spitting fuel, won't rev up - first thing I'd check here is motor full of fuel from bad float or petcock - does it smoke a lot too?
     
  5. dunne

    dunne New Member

    As far as the petcock, I've rethreaded the tank for an 1/8" and put in a nozzle from the hardware store. Got a 3/16" fuel line with inline shutoff and fuel filter.

    I'll pull apart the carb and check everything, but how would I check if the motor is full of fuel?

    Thanks guys
     
  6. crassius

    crassius Well-Known Member

    take out spark plug & pedal to see if liquid blows out
     
  7. dunne

    dunne New Member

    So I drained the tank & carb, removed the carb, turned the bike upside down and pedaled until no more gas sprayed out. I'm using a ngk b6hs plug and have replaced the stock cdi w/ the jaguar performance cdi/ignition. Changed the carb needle to the leanest notch possible, and still wont rev up. Pulled the plug and it's still not discolored at all, smells like gas.
     
  8. Slogger

    Slogger Member

    You didn't mention if you cleaned that float needle and seat. If it's dirty the gas will leak into the carb uncontrolled.
    You should also make certain your new gas shut off in the line actually shuts it off. My original kit shut off started leaking by, I caught it while the carb was off to change the jet and the gas line dribbled all over my flat black clutch cover.
     
  9. crassius

    crassius Well-Known Member

    not reving up can be caused by fuel still in motor - if running it for several minutes (while it smokes a whole bunch) doesn't get it to straighten out, then you may have gasket or seal problems

    look for leaking at head gasket & along case seams - if dry, then check in clutch & mag for seepage
     
  10. KCvale

    KCvale Motorized Bicycle Vendor

    Have you torqed your head nuts?
    Sounds like a compression leak to me.
     
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