What, you think I'm just making this up? Whatever your experience of 'classic era' British bikes has been, mine, back in the late 60's /early 70's, was one where every single person I can remember who rode British had endless trouble with them. Without exception. That may well be because as penniless teens we (they) could only afford clapped out versions, but even when a few moved into buying new the problems continued. For example, a friend bought a new Trident on the back of glowing reports in the weeklies. It went back to the dealer - and then the factory - to fix porous castings and bearing noise from the crank - from new!
The dealer gave him a loaner 12 month old Bonneville for his summer trip to Greece and it disintegrated around him; bits - lots of them - fractured and fell off. When he took it back to the dealer it went back in a van with two carrier bags of broken parts. They replaced it with a Honda until the Trident came back only for it to pack up again the following year on a trip to the Black sea.
OK, a few somewhat knackered swallows don't make a summer but everybody eventually came to the same conclusion - grease under the fingernails and stuck at the side of the road is only fun for so long. They all (those that didn't give up completely anyway) went Japanese in the end.
This was trying to get fork oil into the Bonneville in Greece as the seals had blown. Rough roads maybe but they didn't blow the seals on my Yamaha.