Making my first exhaust

Hello i was just curious just how to make a exhaust and what do u make it out of. Also how do u get it in the block + its a 11.5 hp.

You can either bolt the pipe in or screw pipe in, I think it's 1" pipe that screws in. You could weld one up if you want if you have a welder, or use natural gas pipe and elbows. Just make a adapter from the stock muffler to the pipe that you choose to use. At the end if your exhaust, I suggest making a small braket to support everything. Try to stay away from galvanized pipe, dangerous to inhale when the coating burns off.

There's a few ways to skin that cat, and a lot of it depends on what you have available to you.

First, the engine. IF your engine has a threaded exhaust port (take your factory muffler off and see) then a new exhaust system is as simple as a trip to your local hardware store. On a single, the port is usually threaded for 1" NPT pipe fittings. Grab some nipples and elbows, and screw it all together. Do NOT overtighten the nipple into the block, and I highly suggest some anti-seize on the threads.

Threaded mufflers are available, that you can add on at the end of your pipe too.

Me? I usually go the full fab route and avoid the threaded stuff. I usually start by cutting the port flange off the original muffler, and sometimes I just make a new flange. I select tubing that is slightly larger than the port size, and route it to wherever I want, welding the flange on.

I have made my own muffler before, and will do it again. There are a lot of ways to do this. My next one will be featured in a video, I caught a lot of flack for not detailing my Cherry Bomb.

Whatever you do, support your pipe. You don't want a length of pipe and possibly a muffler just hanging freely off the engine's exhaust port, there's a real possibility for breakage there.