A friend of mine has been working his way through a Honda CB350 café racer project over the past year. He was at the point where it was time to fabricate the exhaust system. His plan was to custom build the entire system from scratch except for the mufflers. He had asked me if I would be willing to give him a hand in completing the task. No problem on my end as far as the willingness goes however I do not have a lot of, I mean any, experience in building custom exhaust. We figured that if we put our heads together we may be able to fabricate something that resembles a corridor for carbon monoxide and hydrocarbons to travel through.
The exhaust system was going to be built from 1.50” x .065” stainless steel exhaust tubing. He had previously purchased various sections of both straight pipe and mandrel bent 45 degree, 90 degree, and 180 degree sections. For us it was a matter of figuring out all the angles and where to cut them. The idea is to TIG weld tack it as we go along then perfom final welding one mocked up.
So he hauled his bike over to my garage and we set it up on a couple of saw horses so that the underside was completely accessible. Unfortunately it is hard to apply any kind of math to this type of procedure. Keeping the exhaust system lengths equal between cylinder 1 and cylinder 2 is important however figuring out all the bends needed to be done by eye. So between the two of us we spent much time holding up pipe and staring at it. My friend has a very good eye for angles and appears to be able to envision the system as a whole much better then I can.
It took an entire day but we managed to get the entire system mocked up and tacked together. I am happy to say that no wrong cuts were made and no welds had to be cut apart for a redo. The symmetry came out fantastic as it aligns great with the lines, and frame, of the bike. All that remains is some time spent performing the final welding. After the exhaust was complete we even found some time to fab up some rear mounts to relocate the foot pegs and foot controls.
The pictures on this post lack some of the specific build details, my apologies. When working with a second person in the shop it is hard to take time out for getting shots of the process. You get what you get and will have to piece the story together for yourselves. Enjoy.