I have a 1997 f3, have noticed that the headlight will usualy start out bright then go dim then bounce back and forth a bit as I ride. I just put a new gel battery in it a month ago have no issues with it starting up or dying (has yet to be put on a charger/tender) so that leads me to believe that it isn't a battery issue or charging issue. I'm using a 5k h4 bulb, any suggestions would be helpful.

 

Check the connections at the harness, headlight, kill switch and hi-low switch.
Take contact cleaner and spray all of the connections.
Use di-electric grease to pack them and then reassemble.
Inspect the harness, itself, for damaged, frayed, etc spots.

When cleaning the connectors, note any, that look heat damaged.
Is the bulb intact? Sometimes they can develop an internal flaw.

Hope this helps, Ern