I was a Suzuki dealer in the 70's and owned and sold several. Really nice bikes. I would recommed that you get a 75 or later (M,A, or B model). there were a number of improvements to the engine that improved rideability and reliability, although the older ones were not bad at all.
The one i should have kept was a blue 1976 GT750A with genuine Suzuki European spec bars and cables, Lester wheels and a custom seat. I got it for a song after the owner snapped a chain and cracked the transmission case. I rode it quite a while but got suckered into trading for a 1950 F-100 pickup.......It was my favorite bike ever.
"The rifle itself has no moral stature, since it has no will of its own. Naturally, it may be used by evil men for evil purposes, but there are more good men than evil, and while the latter cannot be persuaded to the path of righteousness by propaganda, they can certainly be corrected by good men with rifles."J. Cooper