The next step in building the custom exhaust is creating the connection between the cylinder exhaust pipes and the muffler. The pipe of the rear cylinder should fit right in, the front cylinder pipe requires bending. And I want to fix the rear cylinder exhaust pipe to the muffler permanently but the front one should be detachable for easy assembly. So it’s best to start at the back. I didn’t really know how to go with this task, as the exhaust pipe doesn’t sit perpendicular to the muffler (in both directions) and it doesn’t enter in the center of the pipe, so the hole will be an oval and not a cirkel. Also, the exact location is difficult to find.

After a few attempts and trials to find the location and shape of the hole, I got the idea to make a paper sleeve for the muffler and pack it with tape. This way I could cut a large hole for the exhaust pipe to enter, and then fill the hole with more tape to make it fit around the exhaust pipe nicely. Also, I needed to shorten this exhaust pipe. It needs to be even shorter in the final setup, but I’m taking baby steps here to not mess up. Turns out to work pretty good:

After the pipe fitted properly, I placed the paper sleeve back over the muffler:

And marked the hole to cut:

Then, I grinded the hole bigger gradually, test fitting it after every small adjustment, so I wouldn’t cut the hole too big. It did take quite a while, but I’m very happy with the result!

From the top, it looks the part as well!

Stepping back, the result up until now looks promosing:

I will probably first hard-solder this joint before continuing with the other exhaust pipe, so I have a stable geometry to work with.

By the way, turned out the exhaust pipes from Roto are made out of (chromed) copper, not steel or stainless steel… it should work but it’s less ideal, would’ve preferred steel or stainless steel. Bending will probably be easier, but the joint will not be as strong as with two identical materials.