I’ve had the exhaust fall off my Motobecane a couple of times, it’s a somewhat common problem with them and it usually only gets worse as the exhaust port gets worn from continual retightening. The last time I had it out it fell off on me again so I decided to do something about it.
I remembered seeing a post that Rebel Moby had made on the mabecanemobylette forum. simply tighten your exhaust up and mark/take note of the corner you’d like to use and the position of the backing plate. I used a dremel and a small bit and drilled a hole through that corner along with the plate, then another small hole through the edge of the head. You could also use one of the cylinder fins if you wanted. Some safety wire through both of the holes then twisted tight with a needlenose and Wala! That nut isn’t going anywhere if you don’t want it to.
Here’s something that just more of an annoyance for me. I’m running Michelin Gazelles on the Grumpy Dumpies and aside from being a ridiculous pain to put on I think they look a little ugly. The reason is they’re absolutely covered in those little feely tire whisker thingys. Unless you’re draggin a knee around every corner you’re gonna end up wearing them off in the middle and they’ll be on the sides of your tires forever. So out came the side cutters last night and I donated an hour of my life to fixing the problem. The result not bad, I think they look much better.