I love my CB750's, but over here in Oz, due to the 365 day a year riding season, they get a real hammering, and most that I've bought over the years has been stuffed. Buggered big end bearings, main bearings, cam bearings, camshafts, camchains, dropped valves, output shaft bearings, are all too common on CB750 engines. I've got a garage full of engine parts that are "past their use by date".
I wouldn't know about the other SOHC4 engines, I only ever had one other, a CB350F with less than 20,000 miles on the engine, and apart from gummed up rings, it was a gem.
My other infatuation are Suzuki GS1000's, and as opposed to CB750's they are truly "bullet proof". I recently bought a very tired looking example that had been sitting under a tarp in someone's yard near the beach for five years, and it looked like it was freshly pulled out of a salt water drain, so I was expecting the worse.
On top of that, the forks were visibly bent and there were scrapes on the alternator cover, points cover, front fender, the Yoshimura pipe was rusted thru at the header bends, and later I discovered the frame was bent. This thing had been in the wars.
I dumped the oil and filters and replaced them with new ones, removed the old battery and put in a new one, and hit the button, and "VROOM", away it went. No smoke, no rattles, with 50,000 miles on the clock, the engine was like new, and even the charging system was working!
My personal belief is that the big Kawasaki's and Suzuki's of the 1970's were the best engines built at the time, bar none. Cheers, Terry.
