PANHEAD JIM BUILDS A SPORTSTER CHOPPER – PART 7
Now that the 6" Stingray fender is more or less how I want it, I moved on to install a custom sissy bar for the chopper. Since I’m doing a sprung solo seat and p-pad, I decided to go with a short sissy bar based on the Gasbox Chopper DIY Sissy Bar Kit. This kit comes with a pre-bent sissy bar along with some mounting tabs for attaching it to the fender and the frame. All you really need is a welder and you can put this kit together in an afternoon.
DIY sissy bar kit with everything you need to mount it to your Sportster chopper.
Step 1: Custom Made Sissy Bar to Fit Your Bike
I decided to customize my kit by fabricating some different mounts to attach the custom sissy bar to the frame. My goal was to mimic the look of the frame tubes which are welded to the axle plates as well as hiding the fasteners.
I started with a piece of 1” diameter mild steel rod and cut it into two 4” long pieces. I rounded one end of each piece on the lathe to match the rounded ends for the frame tubes.
Then I clamped each piece into the milling machine at a 7 degree angle, to match the angle of the sissy bar and cut a ½” deep x 1-1/4” wide flat onto the end. While they were still clamped, I drilled and threaded the flat to accept a 3/8”-24 stud.
Then it was back to the lathe to drill and tap a 2-1/4” deep hole into the center of each piece. By tapping the ends, I could then screw a 1/2”-13 bolt into each piece which was used to hold the piece in the lathe chuck for the next step. Once the piece was secured in the lathe, a cut a 7 degree taper to smooth out the transition from the 1” rod to the ½” sissy bar.
The final step was to drill out the 1/2”-13 threads so that the sissy bar could just plug into the new mounts.
Sissy bar mount attached to the axle plate alongside an aluminum prototype showing the mounting stud.
Step 2: Custom Sissy Bar Design on Plywood
Probably the hardest part of this process was figuring out how to mount the taillights. I wanted to use three Prism Supply ripple taillights right down the center of the sissy bar and I also wanted to hide most of the wiring instead of just wrapping it around the sissy bar leg.
To get started, I cut out three circles from a piece of wood that were the same diameter as the taillights. Then I measured and marked the position of each taillight on a piece of plywood before screwing the wooden circles to the appropriate spots. I also added a couple more circles to keep the sissy bar squared up correctly. Then I just laid the sissy bar onto the piece of plywood.
Laying on the taillight positions using wooden circles.
To keep the style of the sissy bar, next came hours of scratching my head trying to figure out how to mount these lights into the arrangement I wanted. I imagined “V” shapes and “S” shapes, but eventually settled on the idea of ½” diameter diagonal bars. Using some ½” wood dowels, I finished laying out the taillight mounts.
Final taillight layout.
Step 3: Build Your Own Sissy Bar With Metal
Now all that was left to install a sissy bar on the chopper was to make everything out of metal. First off, I had to figure out the actual angles I needed to cope the ends of the diagonal bars. I used plastic protractor to measure both angles, which turned out to be 20 degrees and 35 degrees.
Measuring angles for coping bars.
Get All the Diagonal Bars Cut to the Correct Lengths
In order to hold the diagonal bars in the milling machine vice at the correct angle for coping, I took two pieces of scrap ½” aluminum plate and cut a 20 degree angle into one and a 35 degree angle into the other.
The next problem was how to keep the diagonal bar indexed correctly after coping the first end. Any amount of rotation would throw off the second cope, so I welded a piece of flat bar to the middle of each diagonal bar.
Every time I clamped a diagonal bar in the vice, I just aligned the flat bar up against the back of the vice to keep the same orientation between copes.
Two angle blocks and a bar with a piece a flat stock added for proper indexing.
What came next was a lot of back and forth between the milling machine and my sissy bar to get all the diagonal bars cut to the correct lengths.
Diagonal bars cut to length and coped.
Hiding the wires to provide added style for the chopper
In this Harley Davidson sissy bar installation, to hide as much wiring as possible, I chucked up each diagonal bar in a lathe and drilled a 5/16” hole all the way through the center.
Then I modified the taillights so instead of just having a hole at the bottom for the wiring to exit, they also had a hole at the top.
Next, I laid everything back out on my plywood and marked the diagonal bars at the places where they lined up with the holes in the taillights.
Finally, I drilled the diagonal bars as well as cutting shallow channels going from the hole towards the taillights. This layout won’t totally hide the wires, but once the sissy bar is chromed and the wires are covered in white shrink wrap, they won’t be too noticeable.
Wiring path indicated by red arrows.
Step 4: Tack the Handcrafted Custom Sissy Bars on Chopper
The final step was to tack everything up with a TIG welder and do a test fit.
To finish installing the sissy bar on the chopper I still need to attach the sissy bar to the rear fender. However, I am leaning towards using the rear P-pad mounting holes as the connection point, so I am going to hold off until I lay out the seat mounts. That means the next article will cover mounting a sprung solo seat and p-pad.
Final positioning for the sissy bar will be determined after adding the seat and p-pad.
If you haven't been following along since the beginning, you can view Panhead Jim Builds A Sportster Chopper - Part 1 and get up to speed!
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