Rear brake bracket
KTM 500 rear brakes are mounted on an aluminum bracket which replaces the torque arm used on '87 models and prior. The bracket is equipped with a number of mounting tabs, some of which can be used for a shark fin rear disc protector, and others that have no apparent purpose. If you are a moto guy, you may not be into putting a lot of protectors on the bike. If that's true, I'm talking to you!
Here is the first piece I chopped up, with comments on how the forces run through the bracket. There's a lot of aluminum that's just along for the ride in this part. The two holes with red arrows coming from them are the mounting holes used for the brake. When you use the rear brakes, the reaction force tries to send the brake straight through to the swingarm pin, as the red arrows indicate. That bar running under the pin (the area to be V-sectioned) is simply for when you step on the brake when you are going backwards. And that doesn't happen much on a motocross bike, and when it does it isn't with much force. So, after hacking that part up, I got another one and did it up right.
So here's the finished part. As you can see, I cut away most of the stuff that isn't needed, and the part weight went from 9.8 ounces to
6.4 ounces, a weight savings of almost 1/4 pound for no money and no loss of function. Just the kind of thing I like to find.
I made 3 cuts with a saw, the rest of the material was removed with a heavy mounted belt sander. I used a very coarse belt, and found that keeping the part cool by dipping it in a water filled cup prevented any clogging of the belt, and kept the cutting speed high. You can see the water suddenly evaporate off of the part, and that's when you dip it in the water again. All done by eye except for the weighing, which was done on digital scales.