Seen people have exhaust flanges come completely off on other bikes during long day rides, and some loose brass nuts as well. So never say never.
Yep, it can happen. It happened to me once.
I was heading to Devonport on the Jota to catch the boat to Australia's North Island to go to the 2013 Easter Broadford Bonanza (blimey, has it been 12 years?). The nuts vibrated off the centre exhaust flange somewhere along the highway, but I didn't notice the change in exhaust note until I slowed down when coming into a town. The exhaust flange was rattling around down near the 3-1-2 collector and the header had shifted a few mm out from the exhaust port. Obviously the nuts were nowhere to be seen and the gasket was also missing. I normally carry a few M6 nuts and bolts as spares, but I didn't have any M7. There was no chance of finding any M7 nuts in a small country town, so I secured the header as best I could with tie wire, and proceeded to the boat. I was a little concerned that the middle cylinder might run lean and overheat, but that didn't seem to be an issue at all. The bike ran just fine, albeit rather noisily.
Once I got into Melbourne the following morning, I found a hardware shop in the city that had M7 stainless nuts. I still had to find a gasket, so I went around the bike shops looking for something of about the right size. But nobody had anything. So I continued on to Broadford without a gasket, and the bike making a "futt-futt-futt" noise from the exhaust port. I managed to scrounge a gasket from someone in the pits that almost fitted. It was a bit small, so I annealed it and then hammered it down the neck of a Coke bottle to stretch it out to the right diameter. It worked well enough to reduce the exhaust noise.
I subsequently had a few fun track sessions dicing with Tom the Wrecker on his Jota and a couple of other guys on Laverdas. Then a girl on a Suzuki Katana shunted me in the rear as I was slowing down to enter pit lane, which cracked the Redax stainless exhaust can on the right side. That trip was a bit of a tough one for the exhaust system. Nothing I couldn't put right when I got home though.
I now carry spare exhaust stud nuts and gaskets in the tool tray.
That was an eventful trip in another way. I was travelling with my mate Russell who had his Laverda 3CL and a race bike on the back of his ute (pickup truck). On the way to Devonport, at the same time my Jota was shedding exhaust nuts, a front wheel bearing failed on his ute. He limped into Campbell Town with a horrible noise coming from a rather wobbly front wheel. We found a car wrecker's yard that had a similar vehicle that we could scrounge some used parts from (he didn't have any M7 nuts though). But the owner of the yard took forever to retrieve the necessary parts. He kept getting distracted by his mate who was trying to fix something else, and we had to keep steering him back to the wheel bearing job. With all the delays, we had to ignore speed limits for the rest of the way to Devonport (about an hour and a half) and only just made it to the boat a couple of minutes before check-in closed. All part of the fun of road trips.
