to add brake lights to a pre 03 blaster:
depending on if you want it to work all the time, or only when the headlight is on ?
will determine if you tap into the lighting power before, or after the headlight switch.
if you still have cable brakes, a brake light switch off another quad, dirt/streetbike rigged to the brake pedal is the easiest way, they connect to the brake pedal with a spring.
i have a few from gsxr's laying here i'd send ya cheap if needed ?
you'll need to fashion a way to mount it above the pedal, welding a tab being the best option ?
if you have hydro brakes ?......
a yfz front hydro brake lever has a brake light switch built in, i think i paid $25 for mine on ebay
you can aslo do the switch at the pedal as mentioned above
or, you can get micro switch banjo bolts and wire thru them.........
http://www.ebay.com/itm/Motorcycle-...Parts_Accessories&hash=item4d18dbd36e&vxp=mtr
be sure to get the correct thread/pitch for whatever master cylinder you use/have