Topic: kawasaki 6v to 12v conversion

[justind511]

ive been reading alot about people converting there old honda SL's to 12v by changing all bulbs and putting in a 12v regulator and battery. i was wondering if i could do the same to this bike. it has 3 stator coils, 1 for ignition and one for heald light and one for all lights. the wiring diagram is attatched. any helo is greatly appreciated

[justind511]

any one?

[kirkn]

Well, I've done the SL conversion, but not a conversion on a system like yours.

Seems like it'd be straightforward - one coil runs the ignition so no changes.  One coil runs the headlight, so you'll want to make no changes there, or at minimum, slip in a 12-volt AC headlight off some off-road only kind of bike, like a Honda XR model. 

The 3rd coil is either going to develop 12 volts under a load or it isn't, to keep your battery charged.  Only way to really tell is slip in a 12-volt battery and the rest of the lights and see... 

I dunno, I don't really see the advantage here.  On a system like yours where the headlight is powered by it's own coil (I didn't study your diagram so I'll take your word for it), you're almost stuck with that headlight.  And, if you're not changing the headlight for better nighttime visibility, why bother?

[justind511]

There are no lights on it right now. 6v ones are expensive and hard to find. I was thinking I would take the headlight could and make that 12v too maybe. I'm going to get a multimeter to see what the lighting coils put out

[kirkn]

OK, I've looked through the wiring diagram.  I see the headlight coil (yellow) and the normal charging coil (pink).

Headlights on = headlight and dash lights powered by that coil with yellow wire (connected to red by the key switch)

Always (headlights on OR off) = charging coil (pink) connected to regulator (M1, light blue by the key switch) AND connected to rectifier (R, blue & white by the key switch).

Now, according to that diagram, the rectifier is a simple diode, which just clips or wastes half of the AC signal, thus making a crude DC which charges the battery and everything else.

If it were MY bike to do, I'd replace the regulator with a "12V pointless regulator" like the Honda CB350 and CB360 twins use.  One wire connected to the coils' combined output, one wire connected to the "downstream" 12 volt system, one wire connected to ground.  Then, I'd use a simple bridge rectifier you can get for $5 at Radio Shack.  I'd connect the two coils - the pink and the yellow - together all the time and send that combined output to both the pointless regulator and new rectifier.  Output of the rectifier goes to your new 12 volt battery.  Then, I'd wire your new 12volt headlight to just be on at the same time as the taillight.  Actually, I'd probably do without a regulator completely to start with.  I suspect the battery would absorb "excess" without much trouble.  I suspect the two coils together won't be generating, say, 15+ volts DC such that you'd even NEED a regulator.

This way, you'd have a very similar setup to a "normal" vintage 12-volt system.

For an even BETTER system output, I'd go into the stator windings and find the ends of the two coils where they connect to ground, and ISOLATE from ground.  Combine those two ends and route THAT end to the other side of your new Radio Shack bridge rectifier. 

That way, you'd have a 'full wave' rectifier, which means that it wouldn't be "wasting" half the AC signal like a simple diode does, but USING it to create an even better overall system output.

None of that is very difficult, but it DOES require a bit of knowledge of what's going on, just so you don't mess up.

Good luck with it!

Kirk

[justind511]

Wow thanks! That's all I needed to know thanks alot!

[justind511]

i ordered a bridge rectifier, it has 4 post, im assuming 1 for each ac input, 1 for ground and one for dc output to the battery?

[kirkn]

Correct - DC (+) output on the rectifier to battery (+) terminal.  DC (-) output to battery (-) terminal or to chassis ground. 

Since your stock system has only one AC output, pick either one of the AC inputs on the rectifier and connect to it.  If you do the stator modification I mentioned, you'd hook the other end (the ends of the coils currently grounded in the stator which you'd "unground") to that 2nd AC input on the rectifier.

Kirk

[justind511]

do i need to hook up blue wire coming from the ignition switch? i think it is the ac current going into the original rectifier to charge the battery. but since the battery wire will be hooked directly to the rectifier do i need to hook it up? or could i put the + side of the rectifier to the pink wire going into switch and then go through the blue wire back to the battery?

[justind511]

ok ive got it hooked up but when i ground the rectifier the temporary light i use gets really really dim and horn doesnt work, but if i leav it ungrounded it seemes to work fine. doesnt matter if it is just the pink wire or yellow wire or both hooked together. is that because of the voltage regulator or should i just not ground it?