engine died while riding and won't fire back up

Discussion in '2-Stroke Engines' started by Soflowrider, May 30, 2016.

  1. Soflowrider

    Soflowrider New Member

    I was riding my 66cc MB today and I was running great up in till 10miles in my trip where it suddenly lost power and shit off. I tried to start and it would not. I have a audio clip (actually took video in my pocket and didn't know it) of it dying out. but it won't let me post a video. I'm sure this topic has been beaten to death but I can't figure it out. I have the two wire Magneto that has a blue and black lead coming out of it. I tried to test ohms with my multimeter but it's reading zero. (Not sure if I'm doing it correct or its fried). The only other time I've had this issue is when I crossed the leads from the magneto to the CDI (black-blue and blue-black) I was thinking of just buying a new Magneto and slapping it on but then I thought maybe it wasn't the issue. Any Info would be awesome.

  2. bakaneko

    bakaneko Active Member

    Probably have to be more descriptive about the not starting part such as is it turning over and dying, just cranking, etc. Also, did u check for a spark in a dark closed garage? Check the wiring to see if it has come loose (blue, black, and spark plug cap).
  3. Soflowrider

    Soflowrider New Member

    Everything was wire properly and the connections are tight, I've had the bike now for about a month or so and it was running fine up until yesterday. When I try to pedal start it sounds like it wants to fire up but just won't crank over. It's getting fuel and has compression. I will check the spark again when I get back home later. I have an audio/video clip of the engine running and dying out but I have not figured out how to upload it to the site
  4. Just out of curiosity was it raining while you where riding or been near water? Any dirt in you're tank? Could be that a small grain of dirt is causing carb to flood. Also check the carb nuts bolts are tight and you're fuel lines in perfect condition
  5. crassius

    crassius Well-Known Member

    black to motor ground should be zero, blue to motor ground is usually around 350ohm (+ - about 40), but can be at 480 for some mags (read this on 1K or 2K scale depending on your meter)
  6. Soflowrider

    Soflowrider New Member

    I was out riding by the beach when it happen. I had a leak in the tank so I had to drain it and JB weld around the studs. I Will clean the carb out when I get back home and try to see if it fires up. But the only time it has ever acted like this is when I wired the magneto to the CDI backwards. Fuel flows out of the hose when I disconnect from carb and carb is full of fuel. Not sure if it's a fuel issue leaning more toward electrical.
  7. Soflowrider

    Soflowrider New Member

    I have the magneto off the motor and when I test with the multimeter I get zero readings. If I do get a reading it's not constant it just jumps around and settles at zero.
  8. crassius

    crassius Well-Known Member

    jumping around could mean connectors are corroded or wires are broken, but I'd say try a new stator
  9. Timbone

    Timbone Active Member

    Here's a trick: remove the air filter. Next time you try to start ( assuming fuel, compression and spark) once you drop the clutch ( preferably going downhill) give it WOT and cover the carb intake with your hand. This will make it really rich and it should pop.
  10. Frankfort MB's

    Frankfort MB's Well-Known Member

    You could try the old finger on the spark plug, if it doesn't hurt. There's your problem. If it does, you know what happens ;)
  11. Soflowrider

    Soflowrider New Member

    Order magneto from MZ should be here tomorrow will install and go from there
  12. jaguar

    jaguar Well-Known Member

    if the stator coils mounting screws get loose or some corrosion forms then the ignition stops working because the screws electrical connection to the stator coils frame is an important ground path
  13. sully1617

    sully1617 Guest

    these magneto's are known for going out like that and since your not getting a reading with the meter it is most likely fried. put a new one on they're cheap enough that you can keep a spare with you in your tool bag, fanny bag or wherever you keep emergency tools while riding. if you don't keep emergency tools and parts you might want to start because these things happen when you least expect it and ten miles from home is a long way to peddle a heavy mountain bike with a engine on it i know this for a fact. i now keep a spare mag and cdi just in case.

    something else you might want to do is get some blue rtv from your local auto parts store and pull the mag cover off and put rtv all the way around the seal to keep moisture out. if the mag gets even a little wet it will fail.
    Last edited by a moderator: Jun 6, 2016
  14. Soflowrider

    Soflowrider New Member

    Replaced the magneto and she runs like a champ.
    Thanks for all the tips/info