1926's end saw the NC taking over from the NB.
While larger NB engines were still being made, the NC replaced the low
end of the NB series. Until 1928 the 1 1/2, 2, 2 1/2 and 3 1/2 hp
engines came with spoke flywheels. In that same year a disc flywheel NC
appeared. This new engine was identical to the earlier NC with the
exception of the flywheels and was available in the same sizes, the 3
1/2 hp retaining its spoke flywheels. Later, the 1 1/2 hp size was
dropped from the disc flywheel series. Some variations in sparkplug
placement and mixer shapes has been noticed; This being more common in
the spoke flywheel engines. The disc flywheel engines gave way to the ND
in 1930. Even so, the spoke flywheel NC was available until 1933.