Lex, I clearly don't ride hard enough or the cracked number plate is a Big 4 problem that doesn't affect the 16H...They are a bigger banger of course so they probably do vibrate more (perhaps therefore the retention of the damped handlebars)...or is it harmonics due to the short tailpiece ?
Rik, I had the tailpiece split twice also! now strengthened with a strip inside, and that cured it, but then the number plate holder cracked, exactly the same as pictured above! so must be the extra stroke maybe, engine doesn't feel unbalanced or vibrating excessively, but I have been putting some serious miles on it, need a rear tyre again!! (3rd one in 10 years!)
Surprised no one else has mentioned this but the spare wheel on the sidecar only appears to have 2 of the bolt holes in the hub!
Was the third hole used with a wheel bolt to secure the spare on its main mounting? Thoughts please including any that may suggest I should visit Specsavers.