Once the headlight assembly is apart, there is quite a bit of room and a lot of possibility to modify it provided the modifier is willing to
hack mangle neatly trim the housing or remove it entirely and then
butcher modify the housing shelf itself.
The City light lens is a small removable molded plastic part; the ID is 39 mm but again, it would be easiest and I think much better looking to just throw that away. That would leave you with the two small chromed projection covers that are wrapped around them. The ID of those is nearly 49 mm but as you can see, it would be easy enough to trim the ID to something like 55 or perhaps even 60 mm so that something else could be installed.
Once the lenses are gone, and the decorative, inner part of the lens liner is opened up, the only other thing in the way are the original two city light mounts and reflectors. These mount in a rectangular box which is covered from the bottom by a plastic cover held in with four push- rivets so the city lights can be serviced. If that rectangular box was modified or entirely removed, the actual headlight bucket would accommodate a fairly big light, light assembly (such as something like an aux. light or even a flashlight housing / lens / reflector), or independent LED's with reflector and the electronics to drive them. The entire thing could be serviceable from the bottom, which is actually externally available when the headlight ass'y is in the bike, as long as whatever cover is made was made waterproof.
Now if the LEDs were purchased separately, mounted onto a heat sink plate, and reflectors fitted, just about anything could be done inside those headlight buckets. If the diameter or at least the height (for a rectangular reflector) of the entire unit was kept to something like 1" or so, the entire headlight housing could be lined with LEDs such as Audi introduced a few years ago but instead of just bright DRL's, they could actually be spot driving lights and regulated through PWM down to some reasonable DRL simulating level. But if pushed to even 80% of their potential, each diode could easily produce 700 or 800 lumens as long as the heat could be managed- I am thinking of aluminum bars to both mount the LED heat sinks as well as wicking the heat out of and behind the headlight housing. It looks like the diodes, reflectors and current control circuitry are readily available in DIY form although finding drivers for 12 volt diodes as well as the 12 volt LEDs themselves might be a challenge.
It would appear that if the original city light provisions were removed entirely, some type of new shape, high- power LED and reflectors could be installed in a small group in the original city light area. Sort of like a built- in driving light. The only downside that I can see is that there would not be any practical way to aim / align them other than accurately positioning the reflectors / LEDs in exactly the right orientation when they were installed.
Brian
I was wondering that exact same thing when I saw your thread about replacing the H4 bulbs and reflectors project. I even thought about asking you for the dimensions of the city lights area, and if there was room behind that area of the housing. However, my project list is already too long, with no free time to do anything, so I didn't.
If your curiosity gets the better of you, and you would like the exact dimensions of these lights, let me know. I think it would be way cool.
