My little lump had everything done to it that could be bought back in the late 70s, short of a stroked crank and lightweight rods; it was Pops Yoshi 590 equipped with Martek ignition and nice light valvetrain. Back then, a set of smoothbores off a 750 was the best I could afford. Suspension was stock, but low miles and overhauled.
It would keep up with my KZ1000 to almost 80MPH, then the big KZ would walk away till the little wing ran out of breath just short of 120. Fun bike, and it handled WAY better than the KZ. In anything twisty, the KZ couldn't touch it. We tried it with various riders taking turns on both bikes, the CB always on top in the twisty stuff.
...and it's only a "decent" handling bike!