No spark, deeper problem

[Jay1258]

Hi my name is Jay. So I recently bought this Chinese motorized bike and it ran amazing for awhile and now has no spark. I tried a new plug but with a simple spark test there was no visible spark. My cdi or magneto could possibly be bad and I will check with a multimeter tomorrow. My main concern is when I opened up the case to look at the magneto, it had a little bit of oil/gas in there. That could have been what fried the magneto but if that's the case putting another one in would expose it to the same problems. Could my unbalanced crank shaft and poor quality seals cause more problems in the future?

I know it's cheap to replace the Mag and cdi but I want them to last when I put them in if anyone knows if my problem is deeper than a part going bad please let me know what to do to fix it.-Jay

 

[crassius]

fuel could be from carb leaking onto cover when bike is leaned onto kick stand, or from the mounting holes for the mag screws

if seal looks good and crank doesn't move when you pry up on its end with a screwdriver, you should be OK

 

[Jay1258]

Sweet, I was hoping my magneto was ok because it certainly looked good, my tests tomorrow will probably point me to the cdi. Good thing I have one of each on the way already!

 

[Windycitybob]

I also put a dab of a high temperature silicone on the engine block where the wires come out of the Magneto because I live in Chicago and it's very wet here all the time so water will get up inside there if you don't fill it up with some kind of silicone and the high heat silicone has lasted stood up to the test of time but now I have no spark and I replace the CD spark plug spark plug wire Killswitch I need to test the Magneto with the multimeter let me know how yours turns out and I got to figure out how to use the multimeter on this damn Magneto's LOL

 

[Jay1258]

Yea I'll definitely share the results but I swear my magneto looked good! I even have the high heat putty sealing the wires. I honestly might just have a messed up cdi or a poorly connected boot, the multimeter will tell all. I was just worried that if I continue to replace parts without fixing the root problem that they will break just the same.-Jay

 

[Jay1258]

So far I've tested my cdi here are the results
Blue neg. And black pos.- 342
Blue neg. And Spark plug wire (w/o boot) pos- 348
Blue pos. And black neg.- no reading
Black to spark plug wire- 5~6 (same either way)
These results are very high anyone know if this means it's shot?

 

[crassius]

I've never seen useful results testing CDI with a meter - if mag tests good and kill switch is unplugged and plug cap is good and plug is good, that only leaves the CDI.

I did build a tester for those here at the shop, but not worth the effort for home use.

 

[Jay1258]

Okay cool, I got home from second shift late as hell last night I'm going to go through the Mag test today or tonight. One thing I noticed is my plug cap was going bad before my problems I tried to fix it more stationary and get the spring in tight but at the end of a ride it died on me and never started again. Is a bad connection enough to mess up a cdi, I'm not quite sure but I think I heard if the spark doesn't reach the plug it could fry the cdi trying to start it.-Jay

 

[crassius]

I've not seen a bad CDI that could be specifically blamed on plug cap, but have seen a LOT of bad caps - if you don't have a spare handy, one can strip back the plug wire a bit and wrap it around top of plug, then put a nut on there to hold it

 

[Jay1258]

Magneto
Black to white-2
Blue to white-360