There is weekend wrenching and there is dealing with design flaws and poor manufacturing. Problems with the CB175 and CB550 that were not regular maintenance (carburetor/timing/valve/etc/etc) related:
* fast cylinder wear (poor materials/manufacturing, engine rebuilds all around)
* unreliable electric system ("mostly" fixed on CB550 with Charlie's solid state ignition and rectifier)
* Leaking gaskets (design flaw)
I know a lot of vintage Honda collectors and a few racers, and also a lot of vintage BMW collectors. BMW motorcycles from the same era do not have these problems.
What gaskets leaked? Side covers? I haven't had a problem with side cover gaskets but I did have some replacement non-JIS screws back out because they were not torqued properly. Can't speak to cylinder wear, my bike has close to 10k hard miles and doesn't compression test real well but does work fine.
Old side cover gaskets did, those were easy to replace. Something else was leaking before the engine rebuild, and then something else entirely started leaking after the rebuild.
* fast cylinder wear (poor materials/manufacturing, engine rebuilds all around)
* unreliable electric system ("mostly" fixed on CB550 with Charlie's solid state ignition and rectifier)
* Leaking gaskets (design flaw)
I know a lot of vintage Honda collectors and a few racers, and also a lot of vintage BMW collectors. BMW motorcycles from the same era do not have these problems.