I was looking for a "cleaner" look for the rear fender and originally considered the Harley FatBob taillight assembly after seeing Doug Shirley's at the 2003 Western Rally but I wanted to eliminate the turn signal housings and there was no way to get additional bulbs into the "FatBob" housing. I decided to use just the lens and make everything else.
Following are some of the details. The lens is from J&P Cycles, "FatBob lens" (part #3400250), description is "replacement red lens", cost was $12.99 as I remember. The three lamp sockets were purchased from an auto parts store, they're for dual element #1157 bulbs and fit into a 5/8" or ¾" hole (I don't remember which and can't find a part number). I used black RTV to seal and weatherproof the gap between the holes and the sockets.
The stock sub-frame (this is the piece the stock taillight assembly and fender are attached to) has to be cut and the new backing plate/license support welded to it. I used a piece of .060" sheet metal for the backing plate and I believe I still have the cardboard templates for cutting and bending it if anyone wants copies. I used .010" aluminum sheet (hand polished) for the reflective backing behind the bulbs and to form the two dividers separating the three bulbs. I may try to form some curved reflectors to fit behind the bulbs to further brighten the lights. They're O.K. but I think there's room for improvement.
I welded two nuts to the back of the backing plate for the two SS machine screws which attach the lens to the backing plate. I used some 1/8" foam weather stripping to form a gasket between the lens and backing plate.
I used two 12-volt auto relays to supply power from the front running lights to the rear bulbs. When either turn signal is activated that unit's running light is turned off to make the flashing turn signal more visible. I probably could have simply tapped into the front running lights and ran wires to the rear but I was afraid the current draw might be too much for the switch and used the front running lights to activate the auto relays which then supply 12 volts to the rear running light filaments. Because the front signal bulbs are so small, I had to use a heavy duty flasher to slow down the flash rate. This meant making a 3-wire adapter to go from the stock socket to the new flasher. The only other purchased items were wire, wire loom material and wire connectors. Yes, I saved the wiring diagram and can make copies.
The center bulb serves the brake and running light functions while the two outboard bulbs serve the running light and turn signal functions.
The original design called for two bulbs and a car-to-trailer adapter to handle the brake/turn/running light functions. The adapter, however, cut the voltage to about 8.5 volts which meant the lights were too dim to be easily seen. I learned this after everything had been assembled and installed so I had to remove the fender, drill another hole, re-do the wiring, add the auto relays, etc.
Rear subframe + bracket, front view
Rear subframe + bracket, rear view
Rear subframe + bracket, side view
Rear subframe + bracket + lights, side view
After the change to a 3-bulb system the assembled unit looked like this
and this...
Comparing with the Deuce taillight
Front and rear signals on the yellow Magna are the Harley Deuce units and were installed in March or April of 2001.
