Debri Variant Moped Spark Problem [Long]

Hi, I have a 1987 Debri Variant SLE moped. Last year, I cleaned the bike, drained the gas, and let it sit in a semi-temperature regulated garage. The bike ran perfect. Upon trying to get it running again, I found that there is no spark going to the plug. Now, I've done a couple of tests and found some interesting (to me) and confusing results. First off, I have a friend with the same exact bike that runs perfect, so we've been comparing ohm values and exactly what wire does what. OK, so I have the problem narrowed down to the magneto. I don't know if it requires any sort of feedback to allow for a spark (i.e., grounds to the taillight). I'm sure the taillight is not related, because I had to replace the taillights when they were both blown, and it ran fine. The kill switch is also functional as I took it apart cleaned it with contact cleaner and made sure it worked by checking continuity. The green wire goes to the coil and the blue goes to (from what I see), the lighting. First, on the running moped, the green wire produces a pulse of electricity (as a spark plug pulses). On mine, the green wire produces a steady current (with no pulse). The blue wire on his produces a steady current, while mine produces no current. The red wire (which I personally find not to be related to the matter) was not tested. There are only 3 coming out of the magneto. The magneto itself shows no visible signs of corrosion. The entire area is clean of any debris and was totally sealed before the cover was removed for troubleshooting. Both the headlight and taillight don't light either (which I believe to be related to the steady-state blue wire which on mine does not light). Before putting it up for the winter, everything worked. Now, when I turn over the motor with the pedal (no electric starter), and turn the switch on (with the motor rotating), one pulse goes through the plug and a nice blue spark goes across the plug. I don't really know a lot about magnetos, but it seems pretty obvious that somehow the pulse is responsible for the spark because the

voltage difference between on and off. So, I guess after all of this, my question is, what exactly would make for a constant power instead of a pulse going to the feed going into the coil. I was told maybe a short in the stator, but since the bike literally hasn't been touched or exposed to any extremes, is this possible? Also, any other suggestions at all about the problem would be greatly appreciated. Thank you.


Re: Debri Variant Moped Spark Problem [Long]

It sounds to me like your points are not closing due to oxidation between the contacts. Try cleaning (or replacing) them and adjusting the gap. When the points open the voltage goes to the coil, then to the plug which results in a spark. Then the points close sending the voltage to ground for a moment which alows the condenser to discharge to be able to spark again. If the points don't close you won't get a second spark.


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