Another option, without replacing/upgrading the alternator, is to use high output, low energy devices. There are two options: HID headlights, and supplemental LED lights. There are HID kits which might be adaptable, if you can fit a much later model's OEM headlight in your bucket. Search e-Bay for "
CB750 HID".
If you want a really robust, high output, LED, check these out:
http://www.webbikeworld.com/lights/clearwater-krista-led-lights/These will draw 72 Watts from your alternator. This product is $600+, but built rugged. A complete HID headlight kit, for my '79 DOHC, was around $400, when I checked a year ago.
Otherwise, here are some 3 Watt, LED's, waterproof, self-contained, wire and go, off of e-Bay:
http://www.ebay.com/itm/350310731409?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_2020wt_1064These will put out 100 Lumens each. If you really want a lot of light, try buying three sets, or six LED's, and cluster them in three's, mounted on your engine guard bar, using aluminum bar/plate stock for a bracket: 600 Lumens, at 18 Watts. I have not hooked the pair I bought up to the power on my Voyager yet (on the bike, just not wired in yet), but in bench tests, with a 12 Volt, 5 Amp supply, each individual light was too bright to look at, even from 20 feet away, in a brightly lit room. If they work well enough, I may buy another set of two pairs to make the 3-light clusters, to really make us noticeable on the roads, and to light up things in the dark. Cheers!
1979 CB750K (sold, 2012, but not forgotten)
1983 Kawasaki 440 LTD Belt Drive (sold, 2011)
1993 Kawasaki Voyager XII