no spark after getting wet


New Member
May 22, 2016
this is my first post. Purchased motorbike for a 100 last night. the guy did not seem very trustworty . this is the story he told me. He said he bought this bike 9 months ago in Seattle, because he lost his driving privileges due to dui. It was riding fine and all that, then when he was moving to Portland he had this bike in the truck uncovered in the rain. couldn't get it started ever since. I brought it home , drained the old gas, then checked the spark. there was none. Here is how he had the wires . black and white coming from engine were going to the black on the cdi, blue to blue and also both wires from kill switch were attached to the blue. I disconnected those right away, then tryed different variations, sometimes wold get intermittent spark, sometimes for more than 15 seconds, but then it all disapeared. Then I went on internet and found one guys suggestion to put cdi into 300f degree oven for 10 minutes to get all moisture out of it. did that. no difference. finally found out that black goes to black and blue to blue. so I cut the wires and soldered then eliminating the clips. no spark. then moved the spark plug boot spring closer to center of the wire. no spark. Please someone provide with detailed info on how to ohm the cdi and the part that is in the engine.


Active Member
Jul 29, 2012
Central Illinois's the good news. This shouldn't be too expensive to fix.

And there probably isn't any bad news. It might be a bit frustrating, but probably.

"the part that is in the engine" is the magneto. It's more that likely that your trouble is right there. Though a new CDI and spark plug probably won't hurt, either.

Sorry. I don't remember off-hand just what the resistance values should be for the various electrical points of the magneto and CDI. I don't need to remember because those values are easy to find when I need them.

At the top of this page you'll spot a little 'search' window. Type in "Magneto troubleshoot" and you'll find threads that give the info you need.

The parts are cheap. You won't have your bike going today or tomorrow. But you can have it going within an hour of when they're delivered.

Best of luck to you.


New Member
May 15, 2016
Fort Wayne IN
Electrical Improper wiring?
BLACK magneto wire to Black CDI wire, BLUE magneto wire to BLUE CDI wire. WHITE…either remove or isolate.
There has been one EXCEPTION in the 3 years that I’ve messed with these engines. The vendor told a buyer (couldn’t get the engine to start) to reverse the wires from the magneto to the CDI. After doing so, the engine started. Keep this in mind if EVERYTHING listed has failed and the engine won’t start.

Kill switch defective. Do not hook it up until you get the engine running. When hooking up the wires, don’t pay attention to colors. One wire connects to the Blue magneto/CDI wires; the other wire connects to the BLACK magneto/CDI wires. If it was running and quite, disconnect the kill switch while diagnosing any problems.
Check that the BLUE magneto wire has a good connection. Re-solder is recommended due possibility of cold solder joints. “The plug in connectors that come in the kit, the ones on the blue and black wires from the engine and the CDI, are notorious for bad electrical connections. I had one, on the blue wire from the magneto, that was crimped onto the insulation and not the conductor. One of the best things you can do when installing the engine on your bike is to cut off and discard those little push-together bullet connectors then solder the wires together and protect the connections with heat shrink tubing.” (Tom)
Check to make sure the small unshielded wire is soldered to the coil base.
Defective magneto..testing All readings are approximate.
Use Low Ohm-Meter Scale 200K Ohms
Check Ohms between BLACK wire and WHITE wire. 2 Ohms
Check ohms between BLUE wire and WHITE wire. 300-400 ohms.
Defective CDI..testing All readings are approximate.


Well-Known Member
Sep 30, 2012
the magneto stator does not like to be wet and usually can't be fixed if that happens - test is easy with any cheap multimeter

check from blue to black for 350ohms plus or minus about 40ohms (some old mags are 250, & some new ones are 480)

if no reading, check that coil ground is still soldered well to the armature (sometimes this solder comes loose) also check that black wire is bolted tightly to motor ground


New Member
May 22, 2016
thanks a lot you guys are amazing. I ordered a kit from ebay. pretty sure this will take care of the problem. if doesnt , I'll be sure to let you know. Thanks again.cvlt1