Well, regarding MZ, I beg to differ.... bought a new MZ trophy sport 250 in 1973, and did a lot of driving on it until 1983, where wife and kids demanded an Austin Maxi 1750 instead
Never had any problems with the MZ, just kept running, parked in the end of my garage for a couple of years, then sold it to a guy with a fine Japanese bike that he did not want to run in winter, so wanted the MZ as a winter run about.. He paid me nearly the same amount as I paid in '73....
But I now have a Honda NTV650 from 1993 as my winter bike, cheap to buy and very reliable - and when the BSA needs a break the Honda comes out
I and 3 more Danes drove to the Czech Republic in 2020 for the BSA International Rally on our BSA bikes, on the way we passed by Zschopau and made a stop at the former MZ factory to pay our respect
Did not stay for long as it was pouring down....
regard
Joergen