Charging System

Hello,
I have a 1984 dr100e that I want to throw on the street. Therefore I need a battery and a way to charge it. Currently the bike has a headlight and a tail light. The problem is that I can not figure out how to hook up a recitifier/regulator to the bike in order to charge the 6v battery i will be installing. I need to know what wires to attatch where and to what kind of devices. I have attached some wiring diagrams so you can understand my struggle.

Is the 1984 dr100e a Suzuki? Ed

It appears to be designed specifically to run and light up without a battery.
That means it runs on AC.

The ignition doesn't use DC so you don't need a battery for the ignition.

I assume you want a battery to get better lighting at idle?

If that's the case, it's not very simple. The problem is that the magneto/alternator (lets call it an alternator to distinguish the output from the ignition portion of the magneto) is wired directly to ground and the lighting is wired directly to ground. That means the only easy way to rectifiy the power into DC is to use one big diode, and it will only be "half-wave rectified". You will only get half of the power, so you won't see any benefit to adding a battery. It won't charge much and the output of the alternator will be so low, the bulbs might not even appear visible when the battery is low and the bike is idling.

It can be converted to "full-wave rectified", using 4 diodes, but requires being able to disconnect the alternator winding from ground which is usually not practical. As an alternative, you can disconnect the light bulbs from ground, but that is also usually difficult since things are mechanically attached as ground. But if that is possible, then you can add a full-wave rectifier (and regulator if needed) to charge a battery and run the lights. This will give a little bit extra light at idle, as long as you spend enough time at speed to charge the battery.

Sometimes lighting circuits like this can burn out the bulbs from too much output at higher RPMs. If that is happening, and that is why you want to convert to DC, an alternative is to use an AC clipping regulator. I've used this one on a Honda XL175 which has the same problems you are dealing with, and it worked. But it also, is not a simple mod, and does not address the dim lights at idle.
s3.amazonaws.com/gpzweb/RegRec/GPZacRegulator.html

Here's what you'd have to do to get a DC charging system happening.

So you end up with two "grounds". One is the original, which is like an "earth ground" and the "new ground" could be considered "circuit ground" or "lighting ground". One of the rectifier's AC inputs (labeled ~ ) connects to earth ground while the negative output (labeled -) connects to lighting ground.

Yes it is a Suzuki

Thank you loudhvx I'm going to try this. Am I right in assuming that since AC is grounded to the classy that I need to keep the DC grounded only to the battery? Your Diagram was very helpful in understanding what I need to do!

Yes. The symbol with the diagonal lines is the chassis ground.

The battery ground must be separate. That is what I called circuit ground or lighting ground and is labeled as the "new ground" because you will be creating that.

Just a word of warning, if this bike was not certified for highway use from the factory installing lights on it doesn't make it street legal. It must have a Federal Highway Use certification on it. If it was a street legal bike at the get-go and someone took the lights off and you want to put them back on then you should be okay.

Rick H.