KDXRIDER.NET

Hey Guys,
I recently purchased a 2001 KDX200. The previous owner had removed the headlight and tailight, replacing them with MX style plastics. I purchased a universal headlight and UFO tail light/fender. When I went to hook them up, I could not get either to come on. I see the Hot and ground wires for each light that were already there from its past life so I feel confident I was hooking it up to the correct place.

Trouble shooting:
With my multimeter set to AC Voltage, I tested both sets of lights wires and had nothing on my meter. For about one minute, they showed 35 volts while running, but after that nothing. And since then I have tested them several times with no luck. This led me to believe that the voltage regulator was faulty. I disconnected the voltage regulator and there was no change. I even unwound all of the wires to try to find shorts with no luck.

After this, I decided to check the voltage coming from my lighting coil. Zero Volts. I figured my lighting coil was bad so I decided to check the resistance of the lighting coil using the method described in the manual. 0 ohms with continuity.

At this point I had decided that my lighting coil was bad, but here is where it gets somewhat interesting. I took of the flywheel cover, pulled the flywheel and disconnected the magneto holder thing. with it completely removed from the bike (except for the three wires going out), the lighting coil resistance is 2.2 ohms, which is within the acceptable range per the service manual. As soon as the magneto is touched against the mounting surface, the resistance drops to 0 and it shorts out. I unwound the 3 wires going to the magneto and there are no shorts between the wires.

At this point, I dont really know what to do. If I knew that my lighting coil was bad, I was planning on rewinding it, but it seems to me that if i am getting 2.2 ohms with it disconnected to the bike, the coil is still good. Let me know if you have any suggestions on how to proceed.

Check your grounds? The plate grounds to the case.

kdxsully wrote: ↑11:15 am Aug 16 2019 Check your grounds? The plate grounds to the case.

Agreed, Check all grounds first. Check all other connections for any kind of corrosion.

Thanks for the replies, when you say check the grounds, are you just talking about the contact points between the magneto bracket and the case or are there other places to check? I didnt see any other areas where wires are connecting to the frame.

smokeyfilth wrote: ↑03:58 pm Aug 16 2019 Thanks for the replies, when you say check the grounds, are you just talking about the contact points between the magneto bracket and the case or are there other places to check? I didnt see any other areas where wires are connecting to the frame.

Yes. The ignition coil acts as a ground for the cdi too, I think.

smokeyfilth wrote: ↑10:55 am Aug 16 2019 Hey Guys,
I recently purchased a 2001 KDX200. The previous owner had removed the headlight and tailight, replacing them with MX style plastics. I purchased a universal headlight and UFO tail light/fender. When I went to hook them up, I could not get either to come on. I see the Hot and ground wires for each light that were already there from its past life so I feel confident I was hooking it up to the correct place.

Trouble shooting:
With my multimeter set to AC Voltage, I tested both sets of lights wires and had nothing on my meter.

Were you checking at the bulb connection point? If so there is a light switch between the coil and the lights, make sure that switch is good.

smokeyfilth wrote: ↑10:55 am Aug 16 2019 For about one minute, they showed 35 volts while running, but after that nothing. And since then I have tested them several times with no luck. This led me to believe that the voltage regulator was faulty. I disconnected the voltage regulator and there was no change. I even unwound all of the wires to try to find shorts with no luck.

After this, I decided to check the voltage coming from my lighting coil. Zero Volts.

You were checking between the black and the yellow wire coming out of the stator?

smokeyfilth wrote: ↑10:55 am Aug 16 2019I figured my lighting coil was bad so I decided to check the resistance of the lighting coil using the method described in the manual. 0 ohms with continuity.

At this point I had decided that my lighting coil was bad, but here is where it gets somewhat interesting. I took of the flywheel cover, pulled the flywheel and disconnected the magneto holder thing. with it completely removed from the bike (except for the three wires going out), the lighting coil resistance is 2.2 ohms, which is within the acceptable range per the service manual. As soon as the magneto is touched against the mounting surface, the resistance drops to 0 and it shorts out. I unwound the 3 wires going to the magneto and there are no shorts between the wires.

Check your lighting coil where the yellow wire is soldered to the coil and make sure there is no short between the yellow wire and the mount bolt/plate. It sounds as if your coil is shorted at the output.

smokeyfilth wrote: ↑10:55 am Aug 16 2019At this point, I dont really know what to do. If I knew that my lighting coil was bad, I was planning on rewinding it, but it seems to me that if i am getting 2.2 ohms with it disconnected to the bike, the coil is still good. Let me know if you have any suggestions on how to proceed.

My two cents : itd be a good idea to get a flywheel puller and at least check out what it looks like underneath, and maybe a spare ignition coil cause they can go bad at any time. I plan on doing this once I get some more money so I can be prepared for long distance rides.

bufftester wrote: ↑04:22 pm Aug 16 2019

Check your lighting coil where the yellow wire is soldered to the coil and make sure there is no short between the yellow wire and the mount bolt/plate. It sounds as if your coil is shorted at the output.

I saw that there is supposed to be a switch between the output and bulb leads, but I do not see one on my wiring. And yes I was testing the yellow and black wire.

I agree with you that it seems like the coil is shorted out at the output, thus the zero ohms when connected to the bike. I have checked the where the yellow wire is soldered by pulling he flywheel and removing the coil, but I will try again.

lizardfungus200 wrote: ↑09:46 pm Aug 16 2019 My two cents : itd be a good idea to get a flywheel puller and at least check out what it looks like underneath, and maybe a spare ignition coil cause they can go bad at any time. I plan on doing this once I get some more money so I can be prepared for long distance rides.

I do have a flywheel puller, I had to pull the flywheel in order to test my lighting coil disconnected from the bike. And it is nasty inside there, it looks like there may have been some water at some point, but like I said the coil tests good when isolated. Only when touching the engine case does it short out.

For anyone who is experiencing similar issues: I ended up tracing all of the wires from the lighting coil according to the wiring diagram found in the manual. I found a couple of wires that were hooked up to the wrong places. The previous owner had done some weird stuff to the wiring. Got it working good now.

Good to hear, congrats on getting it sorted out.

Always something stupid. Congrats on the good news

I might be wrong but isn't the voltage dc not ac as you stated earlier in the post?

No the voltage is AC. The stator is just the stationary part of an alternator, and the output is an AC sine wave. There is no rectifier on the KDX, just a regulator. That is why the headlight appears to flicker at low rpms. At higher rpms the frequency is high enough that the light output appears steady because the filament can't cool off enough to be seen. You do see this if you hook up an LED light though much easier.