The hard part would be adapting a brakelight switch. Wiring it would not be that big of a deal. You would just have to tap in to your lighting hot wires anywhere after the voltage regulator.

I see I didn't even think about a switch being involved. but that does make sense, I am sure that our z400 has a similar set up in order to operate both filaments of the bulb.
I was hoping of some way to run just a light in the rear, I'm not too stuck on having it get brighter with the brakes so If I'll probably end up wiring it to a switch. The main reason I got this bike is so I could ride sand trails with the wife and her 400 without having to fight a dirt bike around deep ruts. but it would probably be good if she knew when I was braking especially if we tried doing any type of night riding.

Skeans definitely let me know on what you find out. I know how to wire things but when you start talking about rectifiers I start getting a little lost,  I'd also need to get a toggle switch of some kind since I did away with my OEM headlight switch, but that's no big deal. thanks for the help on this guys.

That wouldn't be bad at all. and If I could get a brake switch that would work I could also run that, I would just need to run the hot from the battery to the switch and from the switch to the tail light and put two runs of LEDs in the bar instead of just one. (one for the running light, and one for the brake) how big of a battery do you think I should use? hopefully nothing too big that I would need to fab an in frame box for.

I guess I do have an OEM rectifier on my bike, I just now remembered that. but it probably wouldn't put out enough power to charge a battery. the Previous Owner had some junky halogen lights on the front of the bike, I still have those things somewhere.