Hello, I've been browsing for awhile looking for solutions to a no spark issue on a 50cc, to no avail. I stumbled on to lyns multi meter numbers and posted mine below, hoping someone can direct me to my next step in diagnosing the no spark issue. Off the bat the only problem I see is a higher a ignition resistance of 600 ohms. Here are my values


1) Unplug the CDI. In the wiring connector measure theresistance of theACIgnition Power pin to the Ground pin. You should see 400

ohmsor so. What do you measure? 612 ohm
2) Measurethe resistance ofthe Timing/trigger pin to theground pin. You should measure150 ohmsor so. What do you measure? 132ohm

3) Leave the CDI unplugged. Set your meter to measureAC volts on the 100 voltscale. Measure thevoltage on the AC Ignition Power pin to the ground pin while cranking the engine. You should see 40 to 80 volts AC while theengine iscranking. What do you measure? 53 VAC

4) Set your meter to measure AC volts on thelowestscale you have. Ideally this would be 2 voltsbutmany metersdon'tgo down this low. In that caseuse thelowestscale you have. Measure the voltage on theTiming Trigger pin to the Ground pin while cranking the engine. You should 0.2 t0 0.4 volts AC. What do you measure? mine read between .1 and .2
Now for measuring the outputside of theCDI:

A) Leave theCDI unplugged. In the CDI wiring connector measure the resistance ofthe Ignition Coil pin to the ground pin. You should measure less than 1 ohm (butnotzero ohms). What do you measure? 1 ohm

I then measured coil to ground with CD plugged in and cranking and had numbers up to 30 mostly staying around 20 and 10. I tested 2 cdis with around the same numbers. I may have had spark once during testing as I felt a small shock on my hand while holding the spark plug and cranking. I have hopes that its a bad coil but the high a ignition resistance concerns me. Thanks for the help!

 

I should also mention that I did disconnect the kill switch wire from the CDI five pin harness with still no spark. My measurements were taken on the vac 200 setting as that's as low as it goes.

 

Upon further investigation of the wiring harness of the quad, I saw that the remote box has a green wire that isn't attached to anything. It doesn't even have an end on it, could this be a ground wire ? Or is this most likely an antenna or something? Would this cause a no spark issue? Any help is greatly appreciated.

 

the green is ground yes......try grounding it and see what happens

 

I will try it when I get home, thanks for the reply.

 

My comments embedded in Blue:

 

Remote modules have a receive antenna that is about 5 inches long dangling from the module. It is usually a dangling wire and can be any color.

 

Remote modules can cause no spark issues. If you unplug the module then that eliminates that possibility. However, when you unplug the remote module be aware that you can no longer shut off the engine with the ignition switch. You have to use the handlebar kill switch instead. You can fix that by adding a jumper at the remote connector. Else, everything else about the quad will work normally (minus all the remote functions of course).

 

Thanks for the help guys, it turns out that my coil was bad. I get spark now. This little quad has been sitting for a year though so it only runs full choke while hitting the throttle. I'll have to browse the forums again! Thanks again.

 

So I have the four wheeler running pretty well, but I have to hold it full throttle with the choke on to get it to start. After it starts it runs fine, does that sound like a valve problem? Thanks again?