KDXRIDER.NET

I'm getting close to understanding the AC/DC conversion, but all the circuitry jargon really has my head spinning.

KDX200H

The main thing i'm trying to figure out is if a capacitor could fully replace a battery? If so, what specs.. 20,000uF / 22V? Do I just wire it after the R/R exactly as a battery would +/-? What spec VR would I need, 12V? 12 gauge wire? if the answer is no, what spec battery do i need?

The state where I live, i need basically everything to be street legal.. all the lights, blinkers, and horn.

My plan right now is to find a speedo, blinkers, and DS switch from an SR. I already got the tail light off a WR426 and brake hydraulic switches. I'm thinking i can just get LED bulbs for the incandescent sockets. I prefer to keep most everything japanese OE, can i take a R/R off a KLX300? I'll probably need to get the 85W coil too?

Any help/suggestions are greatly appreciated. I mostly get it, just not sure about electrical specs needed. I'm surprised there's not a sticky tutorial for this already. The most helpful thing i've found is a thread from 2015 where bufftester shared some diagrams. Thanks in advance

Juke22 wrote: 12:25 am Jan 08 2026
KDX200H

The main thing i'm trying to figure out is if a capacitor could fully replace a battery? If so, what specs.. 20,000uF / 22V?

16V minimum preferably 18v or 20v if possible (this is just how much voltage it can handle, larger voltage or larger microfarads means larger physical case, FYI).
20,000uF minimum if not 22, 25, 27, 35,000uF.
A 32v 20,000uf capacitor will be massive, but an 18v 20,000uF capacitor will be manageable size.

Juke22 wrote: 12:25 am Jan 08 2026
Do I just wire it after the R/R exactly as a battery would +/-? What spec VR would I need, 12V? 12 gauge wire? if the answer is no, what spec battery do i need?

Yes.

Juke22 wrote: 12:25 am Jan 08 2026
The state where I live, i need basically everything to be street legal.. all the lights, blinkers, and horn.

The big issue here is that when the engine shuts off, the lights will go out in less than 1 second. To be fully street legal, if the bike stalls, you still need to have your headlight, tail light, turn signals, and horn functional.... Some municipalities may overlook this when giving the bike an inspection, but that's what you really need to be fully legal and safe on the roads.

Juke22 wrote: 12:25 am Jan 08 2026
My plan right now is to find a speedo, blinkers, and DS switch from an SR. I already got the tail light off a WR426 and brake hydraulic switches. I'm thinking i can just get LED bulbs for the incandescent sockets. I prefer to keep most everything japanese OE, can i take a R/R off a KLX300? I'll probably need to get the 85W coil too?

It sounds like you've done a good bit of homework! I haven't seen many other people acknowledging the WR tail lights being the exact same as the KDX down to the exact exact same lens, aside from having a dual filament socket for brake light... I discovered this quite a while ago and picked one up, but switched to the Maier MX rear fenders as they are the toughest possible, in order to preserve the expensive OEM rear fender. I do miss the original fender's stylings though.

They make small dual sport batteries, but there's also the 4-cell Antigravity powersports series Lithium Iron Phosphate batteries that are ultralight and expensive....

Try the Trail Tech regulator rectifier unit to save hassles with shopping or buying inferior units

Chuck78 wrote: 07:55 am Jan 08 2026
It sounds like you've done a good bit of homework! I haven't seen many other people acknowledging the WR tail lights being the exact same as the KDX down to the exact exact same lens, aside from having a dual filament socket for brake light... I discovered this quite a while ago and picked one up, but switched to the Maier MX rear fenders as they are the toughest possible, in order to preserve the expensive OEM rear fender. I do miss the original fender's stylings though.

Well, i learned the WR trick from you in another post, hah. Thanks a ton for the help. i think i should be able get this bike legal with the info i have now. I plan to post some photos when done.

Why not just get a Tusk dualsport kit from RMATV? Simplest thing to do with no running around and trying to cobble various things to work together. Has everything you are looking for and comes with complete instructions! No guesswork!! Replace the stock headlight bulb with an LED high and low beam bulb. Get one that runs on AC/DC as described by another member a few posts back in late December. No rewinding of the stator and a headlight that will blind anything that crosses your path. The only thing that it won't do is light the headlight when the engine dies. All the other lights will still work off of the battery that comes in the kit. If you absolutely need the headlight to work with the engine shut off just keep a personal headlamp to wear if this is an actual constant need. There are links pinned to the top of this section that show how most of this is accomplished. Good luck!