Okay, so I replaced the starter with one I got from a store called Power Sports Nation on Flea Bay, 80 bucks delivered. The old one was definitely shot. I had continuity from the positive post to the starter body, not a good thing. This explains the sudden and huge voltage drop.
So, I installed the new stator onto the cover last night. The Ninja 250 R (mine was off a 1996 model) is the correct diameter, and the bolt patterns match right up. The stator is thinner then the stock Hyosung stator, so I had to trim the mounting bolts by 7 or 8 mm. They were too long and I did not want to damage the cover by torquing through it. I de-soldered the connections from the stock stator to use the stock wiring harness, and solder spliced that harness onto the the new stator.
I cut the wires on the new stator at about three inches from the stator, and did my splicing there. I was able to pull the stator wires through the rubber grommet so I could use the stock wiring covers for the Hyosung Stator and make sure I had enough room for the heat shrink. I fed the wires back through the grommet and the long wire shroud running the wires along with the ignition pickup wires. Once I was done with that, I assembled the connector for the new MOSFET AC connector, and soldered the leads onto the connector pieces as instructed in the kit.
Once I finished with this, I mounted the stator to the cover using the shortened bolts and blue loctite. I than attached the ignition pickup onto the cover and used loctite on the pickup screws. DO not want those bolts coming off in the motor. I than traced out a new gasket on rubberized cork gasket material using the cover for the outline. I used the remnants of the old gasket to match up and trace out the internal holes of that gasket. I used a drill bit to punch the bolt holes in the gasket. I matched the new gasket to the cover, and glued it onto the cover with black gasket material. It sat overnight due to a bad storm that rolled through, but I use the soft compound so I can do that.
I mounted the starter this morning, and the stator cover this afternoon. I plugged in all connectors, hooked up all electrical leads to the start and relay, and hooked up the battery making sure to hook up the new heavy gauge power wires from the regulator to the battery.
I made sure everything was torqued to manual specs, and added about 1/4 of a liter of oil to make up for the oil that was lost when I removed the stator cover.
Put in the key, added some gas. And she fired right up. The new starter works great. The RR rook a few seconds to load up, but once it did the lights got nice and bright, the dash got nice and bright, and the fuel gauge actually came to life rather quickly. The throttle response is noticeably improved. It definitely runs better than it did before the charging issue came up, and boy does it put a nice charge on the battery!
I let it cool off (in 27 degree F weather in my shop) for an hour and test fired it again. The starter just dances over now. And the bike fired up in two cranks on full choke in this cold weather. I think the coils are getting correct voltage now, and I think it is helping with the spark and engine performance.
Details on this upgrade are out on ACD. I am giving proper credit to TD (Tony) and Achie for the work they have done on this upgrade.