The Honda CB550 I think is best choice of any of the classic honda motorcycles, and the ultimate in single overhead cam Honda fours. It was nearly as fast as the CB750, had better handling, but was almost as compact as the CB400 four.
The later CB550F2 versions got better carbs and the CB400 four's styling but I prefer the classic looks of the four pipe K models. Some odd problems of the rear wheel hubs cracking, but otherwise for trouble free riding a good CB550 simply has to be in my opinion the best of all classic Honda motorcycles.
The Honda CB550 is a motocycle manufactured by honda. It is considered the younger cousin to Honda'sCB750 and was introduced in 1974 as the CB550K0. Later iterations were produced through 1978 ending with the K4. Furthermore, the CB550 was offered in a Super Sport, "F" model called, simply, the Honda CB550F.
Reviewers were overwhelmingly positive about the CB550 during the 1970s. However, in some aspects the CB550 is lacking, such as braking. Despite reviewers' suggestions, the CB550 is not a beginner's bike. Power comes on suddenly and with lacking brakes, can make the CB550 unforgiving. Furthermore, the handling, when compared to modern sport bikes, is unresponsive with considerable head shake when riding aggressively through corners. Much of this can easily addressed by the average use through the addition of readily-available, higher-quality componentry (wider rims, better shocks and fork springs, braided-steel brake lines and modern brake pads).
Much harder to change would be basic frame geometry -- rake and trail, wheelbase -- and the 550 series was originally blessed by Honda with very good numbers for the time. Largely because of these factors, and the on-line availability of user-generated wisdom on maintenance and improvement, the CB550 still garners respect.