a high wattage bulb puts more drain on the charging system, which wouldnt surprise me if thats the issue, and may have been from the start. I still suspect that something is wrong though. learning to use a multimeter isnt hard, almost every one I've seen ever comes with instructions in english, spanish, french, and sometimes german depending on the particular device.

on a Honda like the CBR, working on these things is SIMPLE. all you need is a few basic phillips(+) and some flat (-) headed screwdrivers, an 8, 10, 12, 13, and 14mm wrench to do most work. I know thats ALL I need to tear almost EVERYTHING on my bike off, pull the motor and pretty much dismantle. oh yes, in some cases a 5mm allen wrench is necessary too. generally for removing body panels.

I too live in an apartment, and I pretty much tear my bike down every sunday for fun or to adjust/diagnose something. your landlord may be more uptight about such stuff than mine, who simply doesnt care pretty much so long as you dont burn down his building or cut his trees down.