Not a road bike, but air cooled Yamaha racers such as the TR3. Bloody seizure prone tempremental buggers. OK if everything was spot on, but any issue with jetting and you needed to have two fingers on the clutch and very quick reactions.
Had one seize under me at about 135 mph, luckily on a straight, but that very swift lock up of the rear wheel before I grabbed it still haunts me.
If a TR3 was bad, a TA125 was suicide, especially if some clot had "tuned" it.
Kev