Hmmm, renewed interest in making electricity. Gotta love the do-it-yourself attitude on this site.
The only reason I can see to coat the coil after winding is complete is to keep the wire from vibrating on itself and rubbing off the coating. Since the KX500 has a slight amount of vibration
, I think you should coat the coil. I visited with a local motor rewind company quite a lot on this issue, and they sent me to Home Depot to purchase two part epoxy that would adhere to plastic. As it turns out, the type of epoxy its not critical, as long as it will bind to the plastic coating on the magnet wire.
As a note, I have removed the stator from the KX125 to try and wind a lighting coil, and the magnet wire on the stock stator IS NOT coated with anything. Since the KX125 stator is built like a circle with lugs on which the wire is wound, I think I can just wrap 20 gauge wire over the top of the stator wire and get enough wraps to ignite a headlight.
On the question of rebuilding the stock stator, most certainly. I used an old stator (it was still in fine shape, but I just didn't need two extras, so I sacrificed it for the lighting coil experiment) and just removed the wire to get to the iron core. When I removed the wire, I found that the stator wire is very small gauge (not sure exactly what gauge, but a motor shop can measure and determine for sure). It also has LOTS of wraps. In order to rewind a stock stator, you will need to match gauge and match the number of wraps. Unfortunately, I'm not really sure how many wraps there are on a stock stator.
If my stator every goes bad, here is how I will proceed. I will measure the width of the wrap with a digital caliper before I remove any wire. I will make an assumption on the thickness of the epoxy, and deduct this amount from my measurement. I would also check the resistence in a stock coil from a friends KX500. Next, I will take the stator to the local motor rewind shop to determine wire gauge, and purchase wire (this stuff is cheap, and the shop I used actually just gave me both 18 gauge and 20 gauge wire on a spool for free. I even tried to pay, but they wouldn't take any money, just wanted me to let them know how it turned out. Cool folks.). I would then wrap the core with enough wire to get really close to the measurement of the old coil. Once the wire is cut, check resistence to make sure you are close. I found that the number of wraps is not an exact science, and getting close seems to be good enough. Based upon my wire removal of a stock stator, I would guess that the stock stator has 1500-2000 wraps, so I will build a little jig to hold the spool and the stator paralell, with a hand crank on the stator. This will help keep tension on the wire as you wrap the core. Once the wire is wrapped, I would install the stator and see if it runs the bike. My guess is that it will work the first time.
Finally, on the lighting coil, this is AC voltage, so will not charge a battery. If you want to run a battery, MOOSE makes a nice little regulator/rectifier that will provide DC voltage. I have thought about running a battery to eliminate the low RPM low light problem, but rechargable batteries are expensive, so just elected to stay with AC voltage as my light is for getting back to the truck at dark, and not for street riding.
Let me know if I can help further. Good luck
Rick
