[TimViolin]

Hey y’all, I got a problem and I am just unsure on where to go next. The bike is an 87 CMX250.

One spark plug is getting spark, one is not. It was not the spark plug, the ignition coils, or CDI.

Testing the wires with a multimeter, the connectors to the spark plugs on the side that does work measured 0.2 Volts while the failing side measures 0. Not sure what these are called so I attached a picture.

I believe that the problem is somewhere in the wiring harness from here to the CDI but I don’t quite know where to go next.

Any help is appreciated

 

[flitecontrol]

Welcome to the forum. I'm not an electrical guru, and don't recognize the part from the picture. Hopefully, someone with more knowledge will weigh in.

 

[TimViolin]

Thank you! And god bless anyone who is an electrical guru because I can never seem to fully wrap my head around how some of that stuff works!

If anybody comes along and the pictures no good, I can take another. But the slots in the pictures are where each of the ignition coils hook up to.

 

[deere245]

Measure voltage going to the coils.

 

[TimViolin]

Thank you for the input, Deere!

I did measure the voltage going to the coils and the failing side has no volts coming from the connectors.

I think the next option is to replace the wiring harness unless someone has a better idea. Never needed to do this before so honestly I’m a little unsure if the entire wiring harness needs to be replaced or if it’s possible to only replace the wires from the CDI to the ignition coil.

 

[flitecontrol]

Does this wiring harness diagram help? https://www.cheapcycleparts.com/oemparts/a/hon/5053e0d0f870021c54be0dfc/wire-harness

 

[TimViolin]

A little bit. Thank you!

That makes me a little bit more confident that the solution is to replace the entire wiring harness. 🙃

Thanks for your help everyone! Now just to find a wiring harness that’ll fit and fix it.

 

[TimViolin]

Thinking about it a little bit: if I was going to replace the entire wiring harness, might see if just the troublesome weed can be replaced on my own.

If they can, I learned something. If they can’t, then we’re just back where we started.

 

[deere245]

investigate the connectors at the cdi and coils
Wire breakage usually occurs near a connector or sharp turn in the wire(stress point).


Wiggle test applies here. Wiggle the wires while looking for voltage. If when you wiggle a spot, you get voltage, then you found the bad spot.

 

[djmg412]

Hey y’all, I got a problem and I am just unsure on where to go next. The bike is an 87 CMX250.

One spark plug is getting spark, one is not. It was not the spark plug, the ignition coils, or CDI.

Testing the wires with a multimeter, the connectors to the spark plugs on the side that does work measured 0.2 Volts while the failing side measures 0. Not sure what these are called so I attached a picture.

I believe that the problem is somewhere in the wiring harness from here to the CDI but I don’t quite know where to go next.

Any help is appreciated

Man I literally just had this exact same problem. I Found that my spark plug was bad, and had an internal short that reversed it's polarity (ground and hot, swapped) everything looked fine but it wasn't. I could pull the boot off of the plug and the cylinder would fire, put it back, nothing. Try New plugs. @$5 you might need them anyway.