I installed a 12 volt LED 1157 board type tail light (red LED bulbs) in my 85 Yamaha TT600N, no battery. Normal voltage with the magneto is to run between 7 and 17 volts. After two years of riding I have had no problems with the lamp. It seems to almost at bright at idle as at high RPM's.
To mount the circuit board I cut a wedge of wood, using hot melt glue I secured the wedge to the back of the light assembly, plugged in the 1157 socket which I glued below the LED circuit board. I than glued the circuit board to the wedge of wood. So far it has stayed together for 2 years of trail riding with out the hot melt glue coming loose.
Before the conversion to LED lamp I was burning out an 12 volt 1157 lamp every time I rode the bike. LED are very forgiving for incoming voltage.
I like the LED board in the Yamaha so much I converted my 95 R100GS to LED. Removed the old plastic chrome plated (most of the chrome had flaked off) reflector and install a wooden shim and glued it together. Around 5000 miles and it is still in place and working. I do have one white LED point down on the plate. If I was going to make the conversion again I would install three white for plate illumination. One works but three would work better.
The Minnesota Airmarshal
Hennepinboy screwed with this post 10-15-2012 at 05:32 PM
Reason: Added R100GS to posting