01 WR426 electrical issues?

Hi everyone,


​So the story goes, I got this 01 WR426 off a mate of mine as he upgraded. It's been a great bike to learn to ride on for the last 6 months or so. The only issue the bike had when I bought it was that the stator looked like rats had been gnawing into it, because a previous owner wound the bolts in too far when trying to pull the flywheel off at some point and chewed all the copper coils up.


So I bought a parts bike with a blown gearbox and no carb to steal the stator out of and some of the missing lights I need for rego. So I swapped the stators over and all the electrics work perfect except I had no tail/brake light. After doing some research I found out that the WR426 runs on AC current and the LED light I was trying to run doesn't like AC current. So further research found I can run a half wave rectifier to send a DC current to the rear light and it should be sweet. So I go buy all the gear I need, fit it all up to the bike, fire the bike up and still no rear light. So I get the multi meter out and start by looking for a voltage, and couldn't really get a reading (which I did read somewhere is normal cause the sine waves aren't a constant 50Hz and some meters can't read the AC voltage). So I start looking at the continuity in the wires and I'm like 90% sure they are okay and there is no breaks in them.


Then out of nowhere I decided that it would be a great idea to connect a blinker globe up to the brake power wire (white wire under the seat?) and see what happens when I touch it to the frame of the bike. Doing this made the bike stop (same as if id hit the stop switch). Problem I have now is the bike wont start at all. I have kicked it and kicked it and kicked it but it still wont fire up, and I can usually get it going from a dead cold start in like 2 or 3 kicks max.


So my question is, what have I fried in the electrics that would cause the bike to not start? Is there a fuse or something in them? or have I fried the regulator or CDI maybe?


And if anyone knows how I could get my LED tail light to work some info on that would be great cause I'm looking at registering the bike as soon as I can.


Sorry for the massive story but I wanted to include as much info as I could




Cheers mate, i have been through all the electrical section in the manual and i still can't figure it out.

So, i tried connecting the spare CDI unit I have (no idea if its good or not) and it still won't start.


All I did was start the bike, connect one wire on a globe to the white wire under the seat and then I touched the other wire of the globe to the bike frame and the bike stopped. Does anyone know how it could cause the bike to not start again?

Do you have a spark at the plug?

Not yet, that was next on the list to check. I dont think i have a socket that will get in there though, that's why i haven't done it yet

You cant problem solve if you dont know what the problem is

No need to get the plug out-pull the plug cap off and put another plug in it and see if there is a spark when its turned over

Okay, so i got busy and have only just made it out to work on the bike again. There is definitely a spark leaving the coil, but i still can't get the plug out to check it yet (great design putting the spark plug under the frame so you can't get in there with a normal socket, well done yamaha). I also tried switching the regulator over for another one i had lying around but it didnt

Whoops accidentally hit send, phones and big hands don't work well together sometimes hahaha.

But yeah, its got spark, and swapping the regulators didn't help. Is there a fuse somewhere on them or something that i could have blown by grounding the brake power wire to the frame?

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