Fabricating Custom Motorcycle Fork Stops on a Vintage Triumph

When building a custom motorcycle you run into lots of small problems, and often how you attack these problems make a big difference in the final result. My favorite thing about a custom bike is often something really small and clean. This shows my solution to some fork stops needed for my bike, which mated a '61 pre unit Triumph front end to an earlier and different style '58 swingarm pre unit Triumph frame. The stops on the lower tree and frame didn't mate up, and I was sure I was going to dent my gas tank in with one quick swing of the handlebars.

I decided to do a simple fork stop that would be hidden by the headlight. This wouldn't necessitate a metal stop smacking into my frame neck, chipping the paint. I started by cutting and filing a small steel tab and welding it to the cast steel neck on the frame, so it just cleared the lower tree.

I scribed a line around the lower tree while it was still on the bike so I knew the steel rod stops would clear the neck, and then proceeded to mark and carefully drill 5/16" holes in the lower tree. I cut the two rods out of 5/16" cold rolled steel, measuring the distance from the tree to the top of my welded tab, and adding in the thickness of the lower tree.

This shows the bottom of the lower tree, after wire-wheeling it and cleaning the cutting oil away before assembly with denatured alcohol, preparing it for welding.



While I was at it, I went ahead and cut off the stock stops from the lower tree and also cleaned up some of the dings and casting lines with a flap disc and grinder.

After a quick grind of the welded tab to smooth it, the tree now fits perfectly and has a nice sturdy stop. Luckily, the fun doesn't end here, and I get to move on to one of the countless other small problems I have to find solutions for on my project bike.

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