All versions of the Express line are powered by an air-cooled 49 cc (3.0 cu in) two-stroke engine.

A 49cc "noped" (as it has no pedals unlike the PA50 Hobbit/Camino moped) which was manufactured from 1977 until 1983, it featured an air-cooled, oil-injected 2-stroke engine.

For the NA50's final year of production in 1981, it received the same upgrades as the NC50 (CDI, auto choke, kick start) as well as a 2-speed automatic transmission.

The NX50, or Honda Express SR (also called the "Deluxe"), used a slightly different engine from the NC50 and NA50, being equipped with a belt driven, variated transmission, larger reed valve block, and slightly different intake manifold alongside a body akin to a moped-scooter hybrid.

The NU50M comes with an electric start, in addition to the regular urban express standard features, including; oil injection, blinkers, 12v battery, cdi ignition, an alternator, oil tank indicator, and beefier shocks and larger wheels than the regular express.