In terms of bodges this is a very minor and reversible one. If it fails to stop a leak one just tries something far more expensive and time consuming. The bodge itself leaves no mark on the cases and doesn't involve any moving parts. By all means spend time and money if you have both to spare. I just use my M21 as transport in the summer months. In the winter it gently decomposes under a sheet next to my workshop. It's never been 'restored' and to call it's rusty condition patina is rather stretching the term. Using the gearbox is rather like stirring porridge, it needs a gentle touch to avoid neutrals, having been abused for decades with a previous sidecar.
However it runs LEDs, a Triumph clutch, a top quality English made electronic regulator [none of that Far East garbage] & has had a complete engine rebuild of the internals. I expect it to happily make another 30 years, far more than I have left.
When I was at school and college the charm of the M21 was that it would run and keep running when pretty worn out; and worn out bikes were all I could afford. They didn't need constant attention and parts to keep them on the road. After a gap of some forty years I'm on my third one, so I suppose my attitude is atypical on this site. When I ride it I'm 20 again, just as long as I don't see my reflection....
