Yes, I'm referring to the 350/400 alternators specifically. The 750 alternator is quite a bit more powerful.
Rewinding may be an option, but there's no direct comparison between a permanent magnet design as shown in that linked site and the induced field type we have. Most offroad engine alternators have a dedicated ignition winding and a separate lighting winding, just big enough to power the stock lights and charge the battery (if it has electric start). There's generally lots of room to wind more turns on the pole pieces for more output. The rotor magnets are usually spinning on the outside of the stator and the coils are quite exposed.
With our bikes, the stator is pretty dang full and the rotor is inside, leaving no room for more wire and a limited space for working if you want to strip and rewind the thing. There are two rewinding possibilities - a stator rewound to make more electricity from the available magnetic field, or a rewound field coil to make a stronger field. I haven't heard of any experiments with either approach, rewinding the field coil brings up the cost/benefit question ie how much more field can you get with the same current draw. If your rewinding increases the coil current for more magnetic field, do you get back as much at the output?
The final possibility is to make a rotor that is more efficient in tranferring the magnetic field, or has permanent magnets embedded in it that would supply a base power that the field coil would add to. So, has anyone ever tried?
The Luxeon bulb is very bright from behind the bike where I would personally want it as bright as possible. There's no reflector action since all the light beams directly from the LED, and off-angle it's dimmer than from straight behind - but still apparently as bright as the stock unit except from side-on. Side-on it isn't super noticeable in sunlight, definitely the stock bulb is better. I'm not too worried whether the stop lamp is bright from the side. There's no white license plate lamp so it isn't "legal" but the stray red light is bright enough to read the plate, obviously you can't tell the letter colour though (blue) making identifying the province from afar a bit tougher. In the dark, so much light is reflected around the inside of the lens/cover that the whole thing is plenty bright from all angles, and impossible (I hope) no miss from behind. The "instant on" stop light brightness is attention getting as well, I notice this with any vehicle with LED tail/stop lamps.
Cleaning up the harness connectors and repairing or replacing switches and fuse blocks where there's a large voltage drop should be the first step in "fixing" the charging system. The induced field alternator is very sensitive to voltage drop - the lost power for the field coil makes less power at the stator. The minimum voltage drop from the battery + terminal in a "perfect" wiring harness is about 1/2 volt at the regulator with the engine running and headlight etc on. This is due to the current flowing through the characteristic resistance of the wire itself. You can eliminate most of this - down to about 0.1V - by installing a relay and fused power lead from the battery to the regulator, activated by the ignition switch (any black wire). I don't know if the extra 0.4V at the field coil will increase the output more than the extra draw of the relay coil though. This does increase your headlight voltage a bit - the harness voltage drop is reduced just because the field coil power is not running through the harness wire any more. Vice-versa too - a headlight relay ups the regulator voltage for the same reason.
The electronic regulator can not produce much more power at idle than the mechanical one. At low voltage (ie battery is discharging) the stock regulator connects the field coil directly, via a switch contact, to the black ignition power wire. No electronic switch device can do better, and most cannot do as well. The mechanical regulator does use some electrical power itself, more than the electronic one but not really much in the big picture. The most an electronic regulator can improve the situation is this lower parasitic draw plus whatever voltage drop improvement results from this slightly lower total field coil + regulator current. My experiments with a mechanical one vs an Oregon Electric unit showed the idle voltages were the same and if one was a tiny bit better I couldn't see it as the actual voltage fluctuates. There was a difference at "charging" RPM. The electronic one held a much steadier voltage once the system stabilized with a fully charged battery, the mechanical one would bounce around between 13V and 16V or so while the OE one just sat at (as I recall) 14.6V. This is just the way mechanical ones work and I don't know if the steadier voltage really matters to anything.
Thanks for the Candlelight tip. Has anyone tried this lamp - does it install to the stock 3-point attachment system?
The 400F bucket is still really small, unless this H4 reflector has a VERY shallow dished shape the protruding hi/low solenoid is not going to fit in there and the ballast will have to be attached under or behind the bucket. I suppose you cut hack off the back of the bucket and let the solenoid stuff stick out.
With my Cibie reflector it's a trick just to get all the wiring in there using a normal H4 lamp.
