I have a naked 2003 Bandit 1200 and have tried several things to improve the lighting. The bike has a single light and fairly good distribution, but I wanted a brighter light with the same wattage ratting (60/55W).
I tried a Sylvania Silver Star but it failed in about 700 miles. The guys at a local MC shop said that other customers had similar failures and maybe the bulb was NOT vibration resistant.
Finally I located a web site <
www.easternbeaver.com> based in Japan, that offered a relay system to improve the lighting. They supply a two relay system that is a plug and play installation and fits into the headlight shell along with the other wiring already there. Only two wires go directly to the battery -- the relays use the original headlight socket to swrtch the power through larger wires and the relays directly to the headlight filaments.
My bike, before installation, had just over a 1 volt drop between the battery and the headlight contact on high beam and about 1 volt on low.
After installation the volltge drop is less than 0.09 volts in either position and the headlight is noticeably brighter even with a stock wattage anti vibration bulb. About the same brightness as the Silver Stars in fact.
At about $50 it isn't cheap, but the results are certainly worth the expense. Check out the web site. Service was prompt, even from Japan I had the kit in 5 days. Installation took 1/2 hour and the hardest part was stringing the wiring back under the tank to the battery.
The kit is well thought out -- the fuse connector has a quick disconnect to allow connecting the fuse AFTER running the two wires undet the tank. I was able to do this with a straighened coat hanger with some care to avoid hooking anything else under there in the process. Then the fuse connects with a bullet connector and the two ring terminals go to the battery. They even supplied a spare 10A fuse which is taped onto the fuse box should it ever be needed.
The web site has good explanations and even discusses higher wattage bulbs with some caveats. All in all, good reading -- of course with the intent of selling you a relay kit.