Home depot muffler extension and exhaust temp?

[jeffyh]

Out of a need to fiddle moreso that cheaper/more practical alternatives, I was walking around home depot looking for ways extend the muffler without a need to bend pipes or weld.

I came across a flexible copper water heater connector w 3/4 FIP and some 3/4" brass compression fittings. Thought this would be great until I found out the connector has a 180°F rating.
Then I found a braided stainless steel water heater connectors which I found are only rated to 200°F.
Then I found a steel braided water heater rubber tubing on amazon which is rated to 350°F.

It looks like rubber can handle higher temps. I've also seen an exhaust kit on SBP that uses rubber couplers. So is rubber really the way to go?

Can anyone suggest a working temp to shoot for regarding 66cc exhaust applications?

 

[xseler]

I ran the copper water heater hose for 5 or 6 months. It did reasonably well when you held the revs down. I've fabbed several variations of 'home made exhausts' over the years. Some of the pictures are in my album.

Good luck!!

(The 'rubber couplers in the SBP's kit are actually high temp silicone. There's a specialty hose place here that sells it for around $10 a foot.)

 

[MEASURE TWICE]

I have used both copper and stainless flexed tube meant for water, but if bumped a bit too often, the heat and vibration cracked at tight bends.

There is the rubber gasket and also a nylon (non-conductive) sleeve at the coupler thread ends. I removed both, and made copper donut rings that added up enough thickness to replace the rubber gasket. The non-conductive nylon sleeve is there to prevent galvanomic corrosion in dissimilar metals in water piping. You don't need it so its tossed.

I finally just went massive cast iron water pipe. No cracks or leaks and have been off roading the bike with it and its been tested to know it holds. The weight is a lot I know.

MT

 

[sbest]

I think that while the corrugated pipe may be convenient for plumbing the exhaust to the back of the bike, it might really dampen any pulse/wave effects going on. For that reason it may be better as a muffler than a resonant pipe. Just a thought.

Steve

 

[Bikeguy Joe]

You can get high temp silicone through model airplane supply/hobby shops. It's not too $$$.
Don't get carried away with the length, it will cut down your top end, mess with your carb settings and increase engine heat.

 

[jeffyh]

I ran the copper water heater hose for 5 or 6 months. It did reasonably well when you held the revs down.

So what happens when then revs go up? Did it fail after 6 months or did you just move on to bigger and better?

 

[Brassneck]

FYI, I don't believe high-temp silicone tubing is oil/gas resistant...thus, ok to wrap around a pipe for stabilizing and/or connecting, but the inside (if exposed to oil/fuel) will deteriorate over time...not sure how long it will take...perhaps months/years? But pretty sure it's not a maintenance free solution for long-term. Replacing them as needed is likely necessary.