Motor wont start, no spark

Discussion in 'Electrical' started by mew905, Jun 22, 2012.

  1. mew905

    mew905 New Member

    My friend recently lost his bike in a fire (which is the same reason I generally use my cell for internet use), and after inspecting the motor and deeming it "good condition", he bought replacements for the broken parts (bike was pristine until the excavator dug it out of the building), including the clutch and throttle assemblies, and a new CDI (blue and black cables were ripped out).

    However after rebuilding his bike, going from a Schwinn Sting Ray to a West Coast Choppers bike, hes been having trouble. The motor turns, the CDI is working (both he and I switched CDI's between our bikes for testing), the motor is getting gas (quite a bit really, pulled the spark plug, it was SOAKED after several attempts to fire it up). and we removed the kill switch just to rule it out. We're at a loss. The only thing I can think of is a magneto failure (fire never touched it so annealing is unlikely, as well as the simple mechanism would be incredibly difficult to fail), or potentially loose wires. Is there anything else I should check? He's getting ready to just buy a whole new motor but I dont think its necessary. As far as we can tell, there's no spark (he spray painted it black so grounding may have been an issue, but we tried the external spark test to no avail).

    Also I'm a bit worried about the soaked plug, seems flooded (we tried around 12 one-block runs to try to start it), and his exhaust is upswept so if we manage to get it going, is it going to be a hazard?

  2. wan37

    wan37 Member

    al fisherman has a trouble shooting link on his signature that would help you.Find one of his post and clink on his no start link....Hope this helps
    Last edited: Jun 22, 2012
  3. mew905

    mew905 New Member

  4. BigBlue

    BigBlue Active Member


    What type of engine are you working with? It would help if you posted what type of engine, so others may be able to help you. I am assuming that you have a 2 stroke HT engine?

    Just make sure no wires are touching the bike frame. Wrap good in electrical tape for now. The spark plug wire maybe bad as well as the magneto connection may need resoldering. Heat could have melted weak connection that now doesn't work. Magneto is just a big magnet and rarely goes bad. Could be the coil. Swap out spark plugs and/or spark plug wires to see if they work on your engine. Don't connect the kill switch until you've got it running.

    Good Luck,

    AKA: BigBlue
  5. motorpsycho

    motorpsycho Active Member

    is there anything hooked to the white wire?
  6. mew905

    mew905 New Member

    No, nothing attached to the white wire yet, we swapped CDI's entirely to rule out his new cdi, everything except i didnt have a spare ngk plug for him to use. I dont know how likely the coil is to go bad but my understanding of physics says a simple mechanism is difficult to kill, but yeah not having a spare coil to play with, im thinking our only option is to check the magneto wires. And its a 66cc grubee gt-5 (both motors are, mines a 2011 model and i believe his to be a 2010), if thats classified under the HT class of motors, then you assume correctly.

    Ps: i did skim through those guides after some searching, and they came to the same conclusion as i did: no spark, cdi ruled out, motor getting fuel, it must be magneto and/or wires. Being that when we salvaged the bike from the scrap heap, the blue and black ignition wires were torn right off and i suspect that the pressure to do that could have easily damaged the connections to the magneto coil.
    Last edited: Jun 22, 2012
  7. Skyliner70cc

    Skyliner70cc Active Member

    Wiring to the magneto is poorly soldered. I always replace wiring and do a better job soldering it in then factory does. Your issue may be as simple as a soldered wire coming undone. Pull the mag plate and take a peak. While you are in there, cut the white wire at the mag.