This is what you want for the headlight on a pregen....
APC H4 Model 60/55w Pair $12.99
http://shop.advanceautoparts.com/web...apc_22650190-p
You have to buy a pair, but I have also seen them in single packs for about $8. The superbrights also have a tendency to burn out quicker. I have 27K on my bike and I've only replaced it once. The superbrights can also use as much as double the power and generate twice the heat. On cars I have seen them actually melt the headlamp fixture.
Anyhow, just cause the fuse is 10A doesn't mean the wiring harness is rated for a continuous load of 10A.
I would replace the headlight with the proper bulb as soon as possible.