Help me understand where I went wrong?

[Kadupult]

I've had my motorbike operational since November, and I've ridden it a total of about 10 times adding up to about 10 miles. I've since replaced the magneto about 4 times, and the CDI twice. Everytime I've had problems with this bike it's been electrical, it'll work for a day or two and never longer than that. Runs like a dream until it just stops mid trek, I pedal it back, and every-freakin-time, no spark.

Now I've read a lot of stuff on here about these kind of problems, even made a post a bit ago that I was positive my CDI was causing my "no spark mystery", but since then I've grown to think it's just my magnetos dying at such a short distance. Most people get a few crappy magnetos out of the box, I understand, but 4 in a row? I don't think so. I'm starting to believe this is my fault, and I've made a list of problems it could be:

I've read that the killswitch can short out the mag, and while I've used my killswitch multiple times to turn of my engine, I can't tell if that's the problem or not, I've always had it wired in when the mag does die.

I've also read that if the magneto gets wet it can die, I live in Texas and haven't ridden it in the rain or on a humid day once, so I don't think this would be the case.

Maybe my magneto isn't grounded correctly? I have my black wire grounded to the mags top left bolt

I might have destroyed my spark plug, but that wouldn't make sense, considering everytime in the past the bike died, all I did was replace the magneto and it starts sparking and running like new again.

Any ideas? I'm really hoping its all me messing up, and it has nothing to do with the replacements I'm ordering.

Thanks!

 

[birdmannn101]

Spark plugs don't last forever. I have changed plugs and fixed my "no spark" problem in the past. Tell us how your black, blue and white wires are connected. A misconnected white wire could be the problem.

 

[Kadupult]

Black to black, blue to blue. and from the killswitch: black to blue, red to black. White wire isn't connected to anything and I just shoved it back into the little white sleeve that comes out of the magneto cover.

 

[birdmannn101]

As long as the white wire isn't touching metal, grounding out the electrical system, it should be okay. I would change out the plug. I found when I ran those 2 stroke engines that the plugs collected oil gas mixture and stopped working. Once the gap was set too close and it was barely sparking.

 

[Kadupult]

The white wire isn't touching any metal. The plugs don't seem to make any difference, it's still not getting spark. Like I said the bike will work fine with a brand new CDI and magneto for a few days and then always die due to something going wrong and causing no spark, but then I switch out the magneto and it fires right up for 2 more days...

 

[birdmannn101]

Well, I don't know why you would have to keep going through all those CDI's and magnetos. My magneto kept working even when it was soaked with oil from a leaking seal. One last thing I would check, just in case, would be the kill switch. I was going to check mine but it is all taped up and it is freezing in the garage. Disconnect the two wires coming from the kill switch to the blue and the black wire from the engine. Put an ohm meter on on both leads coming from the kill switch to see if the reading changes when you hit the kill switch.

If that doesn't help I am at a loss for words. Is there a gap range on the magnetos? I have taken mine out to replace the seal and I remember that you had to be carefull putting them back in so the magnet didn't rub.

 

[Kadupult]

I have another magneto to try, but it's the last one I've got so I'm just making sure I can take all precautions this time before blowing out another magneto. Since I've replaced the CDI a second time, I have had no problems, just magneto issues. The killswitch could very well be the problem, I have ALWAYS had it wired up and I've never tried running the bike without one. I'll try to check continuity on my wires, and I'll look for unwanted grounds etc.

I also read on Great Magneto Mystery you're supposed to rub the varnish off the back of the magneto? I've never done that before... Could that cause this? Thanks for all this great help.

 

[Purple Haze]

One thing it could be is a leaking seal. A leak would short out the mag pretty quickly, especially if you're running an oily fuel mix; i.e. "recommended break-in mix". And yes, you need to sand the varnish off of where it touches the case. Good grounds are a MUST. Double check all connections, those stock connectors are total crap.

 

[Kadupult]

It doesn't look like anything got onto the magneto or into the magneto case in anyway, The only leakage I have from the bike is just a dozen drops or so of oil/gas mix out the end of the exhaust over the course of 24 hours after running the bike, but I read that's normal too. grounds look good, and Purple Haze, I'll sand off the varnish and try again.

 

[Deleted member 12676]

you can kill any transformer by shorting the output wires together.
that essentially is what you do when you use a kill switch in the traditional way, it shorts the output to ground.
Never Ever do it that way with these cheap easy to fry stator coils!
Buy a switch from Radio Shack and use it to interrupt the blue wire. When it opens the circuit no voltage will go to the CDI and the stator coil is not being shorted out. There is a drawing on my site on the CDI pages showing exactly what I am talking about.