Exhaust DIY Exhaust Pipe

[heXed]

Just FYI... this fix did not work in the end.
Ok, so I blew an exhaust gasket on my stock muffler and wasn't quick enough to replace it before the gap caused the bolts to loosen holding the muffler on. With the gap in the gasket, I didn't even hear a difference when the muffler fell off, and it was gone when I retraced my path in search. Since I was running with no exhaust (this is my commute, so I couldn't just park ), I was given an expansion chamber for Christmas. I was ubber excited as I had been wanting to upgrade anyway, but was very agitated to find that the new pipe started coming apart at the seams in under 30 miles. I took it off and am in the process of refunding it, but that leaves me back to having no exhaust on the motor. So, I needed to come up with something and it couldn't involve welding, milling, or anything that involved more than a drill or handtools...

Here's what I cam up with...


I had the copper tube and washer laying around. The copper is a flexible water heater connector and the washer is just a really big sized washer (I have a bunch that I got to set up a washer game in the yard). I cut the ends off of the copper tube and enlarged one end so that I could use the washer to press it against the exhaust port. It was a trial & error process involving ball & flat hammers and different random objects to use as forms, but it finally took shape. The washer had to be have bolt holes drilled in it and the top had to be cut down so that it would clear the cylinder fins... hack saw and grinder attachment on drill. Here is a pic of what I started with..


So, test drive.... still spits some oil, but at least it isn't on the wires anymore, lol. It's loud, but I expected that. Most importantly, though... I have good power and am no longer as concerned with dirt and such getting into the cylinder. I may eventually play around with different pipe lengths, as I assume that will change the performance, but I am very happy with my fix.

I will say, I can't wait to eventually learn to weld. I have so many ideas! In the mean time... point made that you don't have to have a full workshop to come up with something when it's needed. I managed a fix with what I had around and I think it actually turned out quite nice

 

[heXed]

Oh, the wood block... Yeah, so the expansion chamber wouldn't fit on the motor where I had it mounted in the frame. That was a temp fix to raise the motor until I found something better. I am, I guess, also happy to be able to lower the motor back to where it was.

It's been a good day...

 

[bluegoatwoods]

Good job, man!

I wonder if the corrugations in that copper tubing will have some sort of expansion chamber type effect. It's sure to be different. And the chances that it'll be 'in tune' with your engine would seem to be about zero.

But it's just possible that it'll create just enough back pressure to keep your engine from spitting out large amounts of unburnt fuel.

 

[Fabian]

Why is there so much oil covering your engine?

I run my engine at 25:1 and i only have a few small drops of oil clinging to the bottom of the engine.

 

[wheelbender6]

Very resourceful. You could probably make a baffle from a beer can if you want a quieter exhaust a bit.

 

[heXed]

So, It turns out this was a short-lived solution. The copper didn't seem to do well with the heat/vibration and didn't last.
Back to riding with an open port for a while again.

Bluegoatwoods: It certainly wasn't tuned to the engine or ideal, but while it lasted, it was definitely an improvement on no pipe at all and honestly seemed better than the stock muffler.

Fabian: The reason there was so much oil on the engine was from riding it with a blown exhaust gasket and then with just an open exhaust port. Going about 100 miles with no pipe at all definitely lands a great deal of oil/gas on the bike frame and engine.

I have other thoughts on a diy exhaust but they all involve welding, so I'm at the mercy of money right now to get something else on the motor. Still, being my only means of travel, this motor must keep running, so if anyone has ideas, I'm open....

 

[Fabian]

The reason there was so much oil on the engine was from riding it with a blown exhaust gasket and then with just an open exhaust port.

If you were riding it with an open exhaust port, your eardrums would have been blasted to pieces (with potential long term hearing loss), not to mention the rest of the neighbourhood.
A replacement standard exhaust only costs around $15 to $20. A small price to pay to keep your ear drums intact.

 

[bluegoatwoods]

It's too bad the copper didn't work. Though I'm wondering just how it could fail. Did it soften up? Maybe burnt through?

All the same, it's true that a new exhaust for these things is pretty cheap. And that's definitely better than running an open exhaust.

Sometimes I play with notions of modifying my exhaust. About five years ago now I fabbed up a dual exhaust that almost worked. So if you're still feeling the urge to DIY, I'd understand.

Post your results. We'll be interested.

 

[HeadSmess]

they arent THAT loud with out the exhaust. i can still hear the cicadas over the roar...i can still hear bats squeaking but, despite a youth spent playing and listening to metal music yes, i do have tinnitus, i need a fan to be on when im sleeping...


i found a welder on the side of the road yesterday works, too!


all i can think of, if you dont have access to much but big washers and a drill... make a stack of washers, spaced out along some fairly long studs... and then try and find a steel aerosol can and mount that over the top of everything... at least it would be some type of baffle, but then again...they arent THAT loud without the muffler! not compared to say, a lil kx80... which is still louder WITH a muffler...


but, to keep everyone in your street happy...buy a muffler.


if you know a plumber with a sutable tap, you could try threading the port, aka briggs and stratton style, and simply screw steel plumbing pipe on? some of thes ethings have round ports... theyre even quieter with no muffler if you can get all that goop BEHIND you

 

[HeadSmess]

oh. copper.

one, it work hardens, which makes it brittle.

two, it doesnt have much hot strength.

it has to be heated until it glows red to anneal it, which is "softening" it again.


im sure youve noticed coiled copper pipe is very flexible, whereas the cold drawn straight stuff is quite hard... keep flexing the coiled stuff and soon it will be hard as well...

then chuck in some high frequency vibrations, with only a support at one end...