as nights come earlier and I've been riding my ST4 more frequently these days, I've gotten very tired of cars cutting me off, due to the low visibility of the lighting system.
cars actually tend to move out of the way and I rarely get cut off on my BMW, which runs dual 55W HIDs.
so I went and installed H1/H3 HIDs on the ST4. Despite what older threads have said about just adding HIDs, it is blindingly bright and there is a dramatic improvement on how much road is illuminated. Also, I am no longer "invisible" to cars - a very important safety feature.
the installation was straightforward, but took longer as this is an old bike. the hi-beam was done without removing the instrument cluster, but the normal light has the speedo cable in the way. some previous owner had hacked up the wiring on the normal light, so that required some splicing. The hi-beam bulb required a bit of filing on the base to fit, and the spring came flying off, leading to a fun 10 minute search of the garage floor and even more time, as it was not secured to the housing anymore.
I'm concerned about cooking the wiring harness, but the current draw of HIDs once warmed up is less than halogens, and I tried starting the bike with the hi-beam on and the 15 amp fuse did not blow, nor did the bike have problems starting. But as with my other bikes, I'll stagger turning on the lights - give the main beam 30 seconds, then switch on the hi beam (I ride with both on, day or night).
I can't comment on "beam pattern" being incorrect or whatever other anti-HID arguments I've read here; all I know is that I can actually identify a beam pattern now. So far as I'm concerned, I've finally rectified the main weakness of the ST4. I can SEE.