Wont start and its new

Discussion in 'General Questions' started by Rockjaw, Jun 9, 2014.

  1. Rockjaw

    Rockjaw Member

    Hey all..i need advice.
    just installed a 2 stroke 80cc on a fixie thruster 700

    its my 2nd bike..

    engine wont start up..

    what are some common problems for not starting?

    its getting spark ..i pulled the spark plug out and spun the wheel..cant be the cdi or magneto

    Im slumped on this one..everything is installed correct..and yes the fuel switch is on and im choking it.


  2. butre

    butre Well-Known Member

    low compression? too small spark gap? vacuum leak? was the plug wet or dry when you pulled it?
  3. Rockjaw

    Rockjaw Member

    plug was dry...but the spark was very tiny...true..maybe it need a wider gap...whats the recommended gap size?
  4. butre

    butre Well-Known Member

    I use around .030 with good results. If the plug is dry though, my guess is a vacuum leak. go over the intake side with some sort of sealant. Pay special attention to the throttle assembly and the intake side clamp. A good way to find a vacuum leak is to spray a tiny bit of wd-40 on the suspected areas, it won't hurt anything on the bike and is just viscous enough to seal most vacuum leaks long enough to diagnose them.
  5. BigBlue

    BigBlue Active Member

    Here's a no start guide that may help. 1st thing is remove the kill switch or try and push it in several times while starting - mine would stick every once in a while. Plug is dry meaning that your not getting fuel. Try removing the spark plug and putting a few drops of fuel into the cylinder head, put the plug and wire on and see if it will fire.


    AKA: BigBlue
  6. Rockjaw

    Rockjaw Member

    ok awesome thanks! trying that today ;)
  7. KCvale

    KCvale Motorized Bicycle Vendor

    Just a tip if you tried starting a bunch...

    Pull the plug and with the fuel off pedal up the street and back with clutch disengaged to blow out any accumulated fuel in the crank case.
    It's easy to do as with no plug you have no compression and it will simply clean the lower end out.

    Gasoline is not flammable, gasoline vapor is, so a pool of it in the lower end will cause your problem.
  8. Rockjaw

    Rockjaw Member

    nice! thanks!..trying that
  9. LewieBike

    LewieBike New Member

    Actually you want to have the clutch engaged when you do this, otherwise the engine will not spin over.

    A good sign you are getting fuel to the engine is to pedal the bike with the choke on full, throttle open some, the spark plug un-threaded, and the kill switch so the spark is off, and watch carefully to see if you can observe gas vapors or gas droplets coming out of the spark plug hole while it's being pedaled. it's uncommon for new carburetors to take a while to get the gas flowing, but it does happen. There's an NT carb trouble shooting sticky in the 2 stroke engine forum that has a lot of good tips.
  10. KCvale

    KCvale Motorized Bicycle Vendor

    Hehehe, ya, the lever let out which engages the clutch, the whole point is move the engines parts with no plug to blow everything sitting down in the bottom end out with the gas and throttle off.

    Consider it a 'Colan blast' for your crankcase hehehe ;-}
  11. Rockjaw

    Rockjaw Member

    ok got it! thanks ..going to swap carbs with my other bike and see if that works too