where can i find a racing exhaust for a 1977 honda xr75? thanks!
Google search is the best I can offer. If your looking just for the muffler, and not the whole pipe from engine to tail, there are many available at many dirt-bike parts sites. I have no idea how popular these bikes are, and performance parts could be hard to find due to the age. You may have to find a fabricator that can custom bend the pipe and weld on a common performance muffler. I would suggest finding one that has mandrel-bending equipment for high-performance exhaust piping. This involves a mandrel inside the pipe that keeps the pipe round through the bends, unlike conventional pipe benders that creases the pipe through the bends. A mandrel bend therefore has the same cross-sectional are through the bend, where a creased pipe has a smaller cross-sectional area, and is restrictive.
There are these crazy magazines in every supermarket and drug store with numerous sources.