I have converted my AR to a 12v system, giving brighter lights etc.. here I show you what I've done. I'm assuming you have some experience of motorcycle electrics, soldering and measuring, plus the ability to figure out a few wiring changes, so I've just shown the key elements. Because my bike is modified, relocating the battery under the seat, locations of parts and wiring is different to a standard bike.
Anyway.. here goes..
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Step 1: Altering the Stator
The AR as standard has two output wires from the loom for electrical power, the yellow wire powers the headlight, the pink is for charging the battery. The other end of these wires is connected to earth via the small ring connector under the coil. Loosen the top screw, and fully remove the lower screw to allow this ring connector to be removed, then re-tighten screws.
We are going to make the coil a closed loop, rather than to earth.
Step 2: Disconnect Yellow...
Look for the yellow wire, see the extra insulation? Inside here is a joint between the yellow wire, and two copper coloured wires that head off into the coil windings. In the pic you can see I cut this without knowing where the two copper wires were joined... but you can also see the solder joint between the three wires, just below where I cut it.
Cut the insulation away and unsolder the joint to the yellow wire. Solder the ends of the two copper wires back together, and then cover them with heat shrink/insulation tape
Step 3: Soldering
The earth ring connector is easily unsoldered from the coil wire, and now the end of the yellow wire has to be soldered onto the earth wire. Cover joint with heat shrink/tape.
Now the windings are not earthed, the loop goes from the yellow wire, through the coil and out the pink wire. Check this has continuity, and is not earthed to the stator plate.
Refit the stator and flywheel etc.
Step 4: Add Reg/rec
Because my AR has been modified a lot, the location of parts/wiring connections is up to you to figure out, but here's what to do.
I used a common cheap 4 wire12v regulator rectifier available on ebay. This one was a mere £6 from china. The 4 wires are;
-yellow = charging input
-pink = charging wire
-red = 12v output
-green = earth
Step 5: Connect It Up
To connect it all up, you can use bullets for the pink/yellow wires from the stator to the reg unit.
The yellow wire is the feed for the headlight, so further in the loom this has to now be connected to a 12v feed wire (brown). If you unwrap the loom tape under the tank, you should find where about 3 brown wires are joined in a crimp under tape. I soldered the yellow wire to this point, and removed the remaining yellow wire that used to go back to the engine connector.
Step 6: Remove Old Rectifier Diode
You can remove the old charging rectifier diode. If you strip the loom tape you can trace the white/blue wire from the connector that used to come from the engine and into the rectifier, and then the white/red wire that goes to the battery. I removed the whole lot, and used a single bullet for the battery connection.
Step 7: Remove Old Lighting Resistor
Up front, there is a resistor that discharges the unwanted lighting voltage when the lights were off. This has to be removed, so you can either just unplug it (pale blue single bullet connector) in the headlight bowl, or remove the whole thing.
Step 8: Replace Battery and Bulbs
To connect the battery I spliced the red wire from the reg unit into the white wire from the battery, and the green earth wire to the earth wire also from the battery. I also removed the two bullet connector, and found some suitable spade connectors for the battery terminals.
I opted for a Powersonic PS1242. It is about 15mm fatter than the old AR battery. Again, as mine is a modified bike it's no problem, but for a stock bike you may have to research which battery would fit t. You'll need a 12v 4ah.
Now, you have to swap all the bulbs to 12v using similar wattage ones. The headlight is a APF type, I used a 40/45w bulb, but this is perhaps just a tad too much on main beam as the charging voltage drops until the engine is revved up. It might be OK in use, but either go for a 35w bulb to be safe, or try an LED bulb (hard to find, and expensive, I may yet try one though) which would decrease the load a large amount and keep the battery topped up even with main beam on.
Plus you'll need a 12v indicator relay (the old 6v one worked on ours but gave a hyper flash rate). The 6v horn worked fine on 12v.
Now you can turn the ignition on, check the bulbs and horn etc work. Once happy, you can now check the charging, with the bike running, it should be around 14v regardless of rpm, or at least above idle. Switch main beam on, it may drop a little, but ideally should stay over 13v.
And I think... that should be it..
Sorry for the vagueness of some of this! I'm assuming you are an experienced mechanic and know how to rewire some aspects of the loom, and because mine is a modified bike, I cannot be precise about locations of wiring etc.. but I hope you can understand the principles and apply them to your bike.