1970 Red CT-90 K2
These are two good pictures of the first of the classic CT-90 styles, the 1970 K2. The later-style air cleaner that would stay pretty much the same until 1986 is present. The exhaust guards now have vertical, rather than horizontal slots. The reflector is gone from the tip of the front fender. The side covers are now silver-gray, as they were in the K1b. The headlight is now larger and body-colored. In many years the light was black, but during much of the 1970s this would stay the same color as the frame.
Not clearly visible, but present, is an altitude-compensator on the Keihin carburetor. For use in the mountains, you pulled out a small black knob if you were at high altitudes to keep the engine from running too rich. A later carb redesign obviated the need for it, but it was usually present 1969-1973.