Pretty proud of it. I used a pocket bike 'fatboy' expansion chamber which dont seem to be around anymore. Scored it for $35! Because I lack metal shop tools and labour is so expensive in Australia I opted for plumbers copper pipe which has all sorts of ready made bends and pipe diameter reducers. To put it together all I have used is: A hack saw, a tube of 'Quick Steel' high temp epoxy resin putty (great stuff!) a tube of high temp silicone and a hose clamp.
I am going to hack off the end of my stock muffler and join it on, bit of a risk cos I don't want to have to rejoin it back on if something goes wrong...
One comment - you didn't solder the copper fittings....? I'm interested on how it holds up. Mine sees huge abuse....I only have a short amount of copper...and it looks like heck now. The spring keeps mine together - I put some goo in to seal it up but it doesn't last.
Yea I did JB Weld and it doesnt hold up either, it keeps everything together but leaks more and more every ride. Today I bought a couple of sticks of flux coated brazing rod, 1620 degrees working temp, but Im not sure the Mapp gas torch I have will be hot enough.....
Mapp gas might get it hot enough but it might be border line on being hot enough. One word of caution if you are going to use copper in the exhaust I don't recommend you use alcohol fuel or gas with alcohol.
When copper gets hot enough it will react with alcohol and make formaldehyde with is a carcinogen and really smells bad too boot. I can't seem to get the spell check working today so I hope I didn't butcher the spelling too badly.
What I have done is use copper piping which fits snugly into the bends (which it is designed to do). I have high temp siliconed on the inside of these sleeve joints and then applied a ring of the Quick steel putty around the outside. The joint is rock-solid and secure I am not worried about it leaking the question is: Will it take the temperature?
The quick steel is amazing stuff, highly recommended it sticks like glue to metal and sets rock hard. I tested it by sticking a gob on the outside of my stock muffler. It is still there two months later! I also rammed a small bit in between the cooling fins of my cylinder right up against the combustion chamber, it is still there as well and has not become brittle or discoloured at all.
Its called 'QuickSteel' and is manufactured by a U.S. brand called CarGo. Comes in a small tube. Its pretty amazing stuff. comes as a log of putty with two layers which you kneed together then it sets in 15 minutes. It doesn't seem like it will work at first becuase it is tacky and doesnt stick very well while it is soft but as it hardens it just goes like steel. It doesn't seem to be too brittle and you can machine and sand it as well. It handles fuel exposure too so would probably be good for plugging carby jets before re-drilling. I think this stuff is perfect for muffler modifications.
Insulated gloves? If it doesn't hold no big deal I will just pay some tradesman and exorbitant amount to braze the pipes sealed. I am confident that it will hold based on my tests with the QuickSteel. It seems to be remarkably resilient.
I am going to mount the pipe and header to the bike very securely using a combination of hose clamps tie-wire and the Quick Steel. If it does work then I my unorthodox method will be able to be used by everyone else on this forum who lacks access to the necessary tools.
Wish me luck!
Here is a better photo of the putty and one of the joints.
The easiest way i found to increse power and a little more sound was to take apart the muffler and drill a couple of 7mm holes into the long inner pipe.....drill them about 25 mm from the cap end
Replace...and have a go
Even if you find a bonding product that will take the heat, the vibration will get it. Plus the metal will expand and contract as it heats and cools. The bonding product will not expand and contract at the same rate as the metal. So it will become "mechanically unbonded" just from the heating and cooling cycles................................
Yeah the permatex stuff didnt work. I think it reacted with the copper cos it went all bubbly.
Thanks for the offer Scotty. I see you are in Melbourne. I am up in Byron Bay but I am based in Melbourne and should be back end of the year. We should catch up when I get back down mate! I rode these bikes for 6 years all over the city.
In the meantime, the bearing on bucking bar on the piston broke and sent little roller steel rods through the engine one of which was sucked into the combustion chamber and ruined it!
New engine on order plus I have met a bloke who can weld me up a header pipe for the expansion chamber.