Northshore,
You can have the alternator rewound where it will put out more current. Exact amount I'm not sure, but many do when they start adding the driving lights and other accessories. Go to the American Voyager Association site or
AB Bike Board they will have all the information. I think the place that does it is in Morton Grove, Illinois and cost around $175 if they use your alternator take about two weeks.
Buddy G.
This is the information you need.
REWIND UPGRADE (1200) (from stock 35 amp to 55 amp output)- Morton Grove Auto Electric ( 500 S Arthur Ave., Arlington Heights, IL- (847) 965-0372 ) has gained a good reputation for upgrading stock Voyager XII alternators to produce 55 amp output. Price is appx. $185.00- not including shipping (as of 1/29/0

-check current pricing, and it takes about two or three weeks after receipt of your stock alternator. Please tell them you were referred from the American Voyager Association website.
REWIND UPGRADE (1200) (from stock 35 amp to 55 amp output)- A&M Alternator Service, 2419 E. Jackson Street, Phoenix, AZ 85034, (480) 267-0891. The owner is Manuel Olivas. Price as of 3/15/2007 was $100 plus tax and shipping. Thanks to Dennis Lawrence for this info.