I tried the muffler bandage, it lasted about 100 miles or an hour...not sure, I was going 80 miles an hour and could not hear it. Mine completely failed in the middle of my 800 mile weekend rally ride from Sacrmento to San Luis Obispo. There was no way I was going home. The downpipe failed at about mile 65 into my weekend trip.
I bought a patch kit, a soda can, bailing wire, 4 hose clamps and I patched it in the parking lot of the auto supply store. The patch warmed up and melted on like it was supposed to. FYI...IT STINKS!!!
Before the patch:
The Patch before melting:
The patch failed before the next gas stop but the engine did not get hot, the engine ran fine, the oil pressure was fine. I was able to move it back over the hole and tighten up the hose clamps over the hole and it quieted up. I gassed up, watered up, used the head and ate some food and motored on to the next fuel stop and lunch. When we stopped for gas and meet up with the rest of the riding party, the patch had moved again and I was done fooling with it. I gassed up, watered up and rode on until lunch. This process continued until we got to SLO 380 miles from Sacramento. I made a better patch from plumbing supplies from HomeDepot but that too failed. In the end, I spent the weekend sounding like a Harley-Davidson scooter.
The ONLY solution I found with the clunking muffler and broken pipe was a new OEM muffler ordered from the dealer. There are NO secondary market mufflers for a vintage style P250.