I've got a Suzuki VX800 motorcycle, and like many older single headlight bikes, the light output on both dipped or main beam is poor. The low output limits visible distance at night, and so limits speed, and also means that the blinding effect of oncoming vehicles is more pronounced.
I chose an Osram Night Breaker Unlimited +110% bulb with a H4 fitting suitable for the bike. These bulbs claim to give 110% more light output, but still fit into the standard fitting, and draw the normal 60/55 watts. This means that they are a direct replacement to the existing standard headlight bulb. I did consider upgrading to a Xenon HID headlight, but a proper upgrade kit costs considerably more, and requires adding a ballast unit and modifying the bulb wiring.
The process for replacing the bulb is exactly the same as for most single lamp 'naked' motorcycles. Here's a quick summary:
Now for the moment of truth: is the extra cost for the Osram Night Breaker +110% bulb worth it? I've done a before and after shot. In both cases, the camera was locked to the same settings (1/500th at F4) so that you can compare the light output.
Headlamp with Standard Bulb
Headlamp with Upgraded Bulb
You can see from the before and after images that there does seem to be a considerable increase in light output. The slight change in the background is because the sun came out as I was swapping the bulb over!
In practice, riding through Dorset countryside on a dark night, the new bulb gives considerably greater visibility at long range, giving reflections from road signs and cats eyes for a massive distance on straight roads. Even on dipped beam, the extra light gives better visibility of the road surface ahead when facing oncoming traffic. No-one flashed me or otherwise indicated that the new lights were blinding them, so the beam pattern has not been affected.
On main beam, it's much easier to see further into corners. The light is brighter and whiter, which allows for more scatter, so even objects not in the direct path are more visible. For a cost of £14.99 for a pair of bulbs from ABD.co.uk (I saved one as a spare), the Osram Night Breaker has to be the most cost-effective upgrade I have made!