gas leaking from head - engine won't start

Discussion in 'Whizzer Motorized Bicycles' started by Godzilla Bobber, Jan 22, 2010.

  1. Hi everyone,

    I have a WC1 with a recently installed cylinder replacement kit and new carburetor and and copper gasket. The parts were purchased from Quentin and installed by the prior owner. The bike ran when I purchased it.

    Chased down an electrical short but I now have a spark. It is blue/white, but having nothing to compare to, I do not know if it is weak or strong.

    Compression seems OK. If I attempt to roll the bike without the release , the rear tire drags. I did remove the head, sanded it on a flat surface and tightened the bolts in the correct order and to the recommended torque.

    Cleaned the carb and the float seems to be doing it's job. I can't identify the jet size. Brand is Kie Han. Throttle and choke seem to operate normally.

    When attempting to start it, I get intermittent firing while pedaling and then there is gas running down the outside of the exhaust pipe. There is a small crack in the exhaust gasket. Gas also appears to be seeping past the head gasket on the exhaust side although it may be coming from the exhaust gasket and just flowing down along the head. Hard to tell exactly.

    Any suggestions?

  2. Maybe I left too much information.

    If the carburetor is functioning properly, should there even be enough liquid gas to drip?

    I appreciate any hints anyone may have. I'd really love to get this running.
  3. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Randy,

    If you have a compression guage you might want to check the numbers. You should have approx 110 pounds with the throttle wide open.

    Make sure the green wire on the coil is ground, and make sure the green wire going to the CDI is open [not grounded].

    I would also suggest removing the spark plug, shutting off the gas supply and turning the motor to remove any fuel build up in the combustion chamber.

    Often the spark plug will fire, but not under load, therfore if you haven't changed the spark plug it might be worth trying. Many times it has been a defective spark plug, so be sure to consider the possibilities.

    The carburetors used on the Whizzer easily "plug up", and most often it is the smaller passages and the pilot jet, either will cause the motor to "flood' or become very hard to start. You might try a small amount of starter fluid in the carburetor to see if it will fire.

    Seems like the fuel isn't igniting correctly because of your comments about the gas dripping.

    I have also worked on a few motors where the gear on the camshaft spun and caused it to be out of valve timing, therefore it might be wise to check the camshaft, lifters, and tappet clearance.

    Have you removed the sidecover and re-located the timing dots?
    Does the motor have the hi lift camshaft & mushroom lifters?

    Feel free to call me on my cell if needed 252-475-0406

    Have fun,
  4. Thanks Quenton!

    I'll try your suggestions.