The First Blewie Pipe?
In the late 50's I was riding my 200cc DOT in the Greenhorn Enduro. For you young guys, a DOT was a bike made in England with a 2 stroke engine. This was before the expansion chamber had been invented. The hot pipe for racing a 2 stroke in those days was just a straight header pipe about 12" long.
Since this was an enduro, I had the stock pipe on. It came out of the cylinder with a short, 3-4" long pipe, then into a can about 6" in diameter. Out of the can was a longer pipe that took the exhaust out along the side of the bike towards the back. The can was a two piece thing with a bolt running through it to hold it together. Somewhere out on the course, the bolt vibrated out and the can came apart. Both pieces fell off. Some guy riding close behind me, hit the short piece of the pipe that fit into the cylinder. I stopped and picked up the piece the guy had hit. The can was now squashed like a flattened megaphone. I was able to get it attached to the cylinder again and continued riding like that, but it ran a lot better that way!
At one point I went sailing up a sandwash and passed Nick Nicholson on his Greeves. Nick was the West coast Greeves distributor. At the end of the day, I was cleaning up in the pits and I noticed Nick had walked up and was looking at my bike. He wouldn't come up and talk to me, but he kept some distance and just stared for a few minutes. The next year, some of the Greeves models, had that "squashed megaphone" type pipe, which became known as the "blewie" pipe...
Editors Note => My 1965 250 Montessa had a "blewie" pipe -- one of the reasons my hearing is gone!