Exhaust stack

I would just take the old one to a muffler/exhaust pipe shop. They can duplicate it and use your old flange.

The pipe size isn’t critical as long as it isn’t more that 1/8″ smaller. Muffler shops will have pipe expanders to compensate for the metric pipe size. I found a regular elbow that fit perfectly over the metric pipe with just a little persuasion.

Just tossing out some ideas.

Standard exhaust pipe is fairly thin so that it can be easily bent to any shape needed. That leads to a shorter life span. Perhaps a heavier walled pipe would be appropriate in this application. Does it have to support the muffler without any other brackets? This piece still has a flange on each end? Post a picture of the current setup if available.

Maybe you could use standard plumbing pipe fittings welded into the shape you need and with the flanges welded onto each end. The flanges themselves should be fairly straight forward to manufacture out of plate steel. Schedule 40 pipe fittings might be overkill but they should last forever. 🙂

Steel pipe that is thicker walled than exhaust tube but thinner than schedule 40 stuff should be able to be bent into shape, but if not, it can be cut and welded at the corners. More tedious to make but more flexible in design.

Speaking of flexible, a lot of modern vehicles use a braided flex pipe from the header to the main exhaust pipe or sometimes all the way to the catalytic converter. It might take a lot of searching, but there might be something out there that would work for you. The problem would then become how to support the muffler with some kind of bracket.

EMT electrical conduit is somewhere between schedule 40 pipe and exhaust tubing but your bending radius is going to be restricted to that of schedule 40 pipe.

If you want something that will last forever, I suggest using plain black steel butt-weld short radius elbows.

Agreed. I wasn’t thinking of bending the schedule 40 stuff but rather trying to find a pre-made elbow or two that could be welded together to get the needed configuration, then weld the flanges to that.

Luckily around here there are a few custom machine/welding shops that carry a lot of different steel products and are very good at “in the field” engineering. If we think up something they don’t have supplies on hand for, they can usually get them in a day or two.

EMT can be problematic to weld in the smaller configurations. Never having messed with anything larger than about 1″, I am guessing that the wall thickness increases with the diameter so that something in the 2″ range may be quite easy to weld. Just beware of ventilation when welding galvanized items.

I am sure something can be fabricated once the right parts are located. I always enjoy these kinds of projects if I’m not under time pressures.

Looking back at the original post, have you tried looking at the online parts catalogs of a Jinma dealer to see if you can find the exhaust part that looks like yours? If you are sure that it came from a different model Jinma once you find something that looks right, one of the dealer/sponsors of this list may be able to get actual dimensions for you.  If you can take a picture of the part you are looking for and post it that should help a lot.