The Honda CB750A was produce for three years, 1976, 1977 and 1978. It was based heavily on the original SOHC CB750K.
I owned one of the 1st CB750A's, a 1976 model, Red, Factory 4-1 exhaust, Not very quick off the line but smooth and easy on tires and chains. Gas mileage was not great, about 40mpg opposed to my '72 CB750K average of 50+mpg.
The '77 and '78 models were equipped with factory 4-2 exhaust.
The Hondamatic may have done better as a full automatic with 4 gears minimum, not the 2-speed manual shift it was. The "Automatic" was very similar in operation to Hondamatic Cars of the same vintage. Auto transmission's for small vehicles were not very advanced back then.
Still it made for a fantastic commuter bike here in Sunny Southern California! I wish I had kept it instead of my 1st wife!!

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The DID rims (17" rear wheel) were gorgeous from Honda. Kick starter was stored under the seat (Did not work very well) and there was a parking brake. Pull a knob out under the tank and press down on the rear brake pedal to lock the rear brake.
No tach, just suggested speed ranges on the speedometer. The pseudo tach housing contained three lights "N", "L", and "D" (Neutral, Low, Drive) and a real working Fuel Gauge!
My now 36 year old Son helping Dad get ready for a ride!
Here is a set of pictures I have kept from somewhere of the same model years as my CB750A.
1976 Honda CB750A Hondamatic"