66cc 2 stroke magnito problems

Discussion in 'General Questions' started by MotorizedMatt, Aug 26, 2010.

  1. MotorizedMatt

    MotorizedMatt New Member

    Hi guys,

    Lately my magnito has been giving me slot of problems. I originally took it to a shop and they seemingly fixed the problem, yet the next day I couldn't get the bike to start after I had ridden it to school. Then I took the magnito out wiped it off and replaced it and the bike ran great again. Now this morning it started up, but died after about half mile and I couldn't get it to start.

    Anyone know why I'm having these issues? I know for a fact it is the magnito too, should I buy a new one?

    Any insight is appreciated as I need this thing to run since it's my transportation.

  2. MotorizedMatt

    MotorizedMatt New Member

    There was a very small amount of oil on it.
  3. GearNut

    GearNut Active Member

    The only way oil could get in there is if the crank seal is not seated properly or has failed. It is behind the magneto rotor.
    It should be installed flush to the surface or slightly recessed in the case.
    Also, if the seal is leaking oil out it is also leaking air in which is as bad as an intake leak.
    This can cause difficult starting and poor operation.
    If you decide to remove the rotor, mark the outer face if it with a sharpie, crayon, scratches, ect. It can easily be installed backwards which would throw off the ignition timing causing the engine to not run at all.
    Also, it is much easier to work on the rotor if you first remove the stator, that way you will not be fighting against the magnetic pull between the rotor and stator.
    Watch for the woodruff key, don't loose it.
    Superglue the key into the keyway in the shaft when you re-assemble.
  4. MotorizedMatt

    MotorizedMatt New Member

    Thanks for the info.

    Update as of yesterday: I took the magnito off again and there was a small amount of oil on the backside of it, which I wiped off. I'm not sure how, but the blue wire came off, so I soddered it back onto the magnito. After that the bike fired right up, and I rode it around all yesterday night (about 10 miles).

    Fast forward to this morning. I start the bike and it runs for about 2 mins then just dies as I had it idling. I started it again and began my trek to work (5.5 miles) and it didn't die once. I'm at work now, and I have a gut feeling that its not going to start come 5pm.

    Could that small amount of oil on the magnito be causing my problem?
  5. Al.Fisherman

    Al.Fisherman Active Member

    I could but I doubt it. If there is seepage as you say, it is really best to replace seal as GearNut recommended. If that is out of the question for the time being, and you are concerned about the oil, and the seal seep (vacuum leak) is not having effect on the running engine, here is is temp solution (I don't want to say fix).
    The seal could be seeping from either the seal to case or the seal to shaft which is most likely. Remove the magnet and coil, clean with some break cleaner or carburetor cleaner, or the like...something that won't leave a residue. Take some ATV and smear around the seal (light coat), making sure that the seal to case is sealed. Now take a freezer storage bag (thicker then most plastic wrap), and cut a piece that will be able to fit behind the coil and that all coil screws can go through when the coil is replaced (to hold it in place). Poke a small hole where the shaft will come out. Slide over shaft, replace the coil and magnet. Any oil seeping will gather on the bottom of the magneto compartment from the backside of the plastic and can be checked and cleaned by removing the magneto cover periodically. I had a seal seeping, did this and found out that the seep was between the seal and case. End result was the RTV did a permanent fix.
    Last edited: Aug 27, 2010
  6. MotorizedMatt

    MotorizedMatt New Member

    Thanks for that info I'm deffinately going to try that later. Could that little amount of oil actually be it though? And when you say seal is that behind the center spinning metal peice? Because I don't remember seeing any seals from when I took the magnito off, it looked like the oil was coming through the screw holes.
  7. BiMoPed

    BiMoPed Banned

    The screw holes do not go all the way through into the crankcase
    unless Chinese "quality control" screwed up.

    Yes, the rubber seal is around the shaft. There is one on both sides of the

    If you can see or feel behind the magnet is the rubber seal flush with the case?
    Sometimes they are not not pushed all the way in.

    Last edited: Aug 27, 2010
  8. MotorizedMatt

    MotorizedMatt New Member

    I will check this later when I get home, but If the rubber seal wasn't pushed in all the way wouldn't it hit the spinning metal? Either way I'll take it off and check the status of those seals.
  9. MotorizedMatt

    MotorizedMatt New Member

    Alright it's deffinately leaking from the seal behind the shaft, would epoxy be okay to put around the seal to prevent leakage? Or is the method stated above the best option.
  10. GearNut

    GearNut Active Member

    Epoxy might work but it will be very difficult to work with later.
    Black or red ATV silicone would be much better.
  11. MotorizedMatt

    MotorizedMatt New Member

    I did the recommended proceedure to combat that oil leaking (see picture) And the bike worked great for the day, but about 1/2 a mile from home it took a dump again and wouldnt start. I took the magnito off cleaned it off and wouldn't start either. I'm ready just to get a new motor to put on it.

    Anyone know of a site sponsor that sells the 66cc 2 stroke, just the motor, and will ship to CA?

    Attached Files:

  12. oologah

    oologah Banned

    I get mine from Gasbike.net or Kingsmotorbikes.com, they are the same company. The motor is $155 but the kit is only $149 take your pick. I think they're in Van Nuys. These are the Grubee engines. I think gas bike is in the sponsor list at the left..
  13. MotorizedMatt

    MotorizedMatt New Member

    Update: I'm working on the bike right now and it is getting spark so I'm assuming the magnito isn't the problem right now. I took apart the carb and nothing is clogged, I'm perplexed as to what the issue is right now.
  14. GearNut

    GearNut Active Member

    Got milk?

    Ha! :)

    How is the wiring between the mag and CDI?
    Are you running the factory spark plug wire and cap? They are garbage and cannot be relied upon.
  15. MotorizedMatt

    MotorizedMatt New Member

    Nope. Im running a high grade wire with a longer cap (not sure what its called)

    Problem now is the bike is getting spark, and I visually verified this, and it is getting gas, cleaned out the carb and checked the lines, yet it won't run now. I think the motor must be blown, right?
  16. GearNut

    GearNut Active Member

    Not necessarily. Does it have good compression?
  17. GearNut

    GearNut Active Member

    Also, have you tried starting it with starting fluid or carb cleaner?
  18. MotorizedMatt

    MotorizedMatt New Member

    How would I check the compression? It seems like when I try to start it the motor has considerably more drag than before when it wouldn't start.

    Haven't tried carb cleaner yet, would I just take the filter off the carb and spray it in or take the whole carb off?
  19. GearNut

    GearNut Active Member

    Leave the carburetor on, remove only the air cleaner cover and element.
    Open the throttle all the way and give a small, short spray down the carburetor throat.
    Close the throttle, leave the choke off, and try to start it.

    To test for compression the shade tree way, remove the spark plug, leaving it connected to the spark plug wire, and tape it to the cylinder head as if you were checking for spark. This will protect the CDI box.
    Now, hold your thumb firmly over the spark plug hole while turning the engine over with the back wheel. Sometimes this is easier with someone else's help. The compression inside the cylinder should easily be strong enough to blow air past your thumb.
    If not, the compression is weak.

    Engines only need 3 things to run.
    1. Air and fuel at the proper mixture.
    2. Proper compression.
    3. Ignition at the correct time.

    If your engine does not run, it is missing one of these.
  20. CrazyCabbie

    CrazyCabbie New Member

    Kill switch?

    Have ya tried to run it with the kill switch disconnected?
    I had the same problem fer a week n just figured it out now... crappy kill switch, lol. I just unplugged it... gotta be sure the brakes work good to stop/stall it