Produced from (1966-1979) the Honda CT90 in its classic form was an 89cc 4-stroke air-cooled single with a four-speed transmission and a semi-automatic clutch, coupled with a 1.867:1 ratio reduction box that was manually switched into operation using a small lever under the transmission case. The cylinder was nearly horizontal in the step-through tube/stamping frame. The fork was originally a leading link suspension, replaced in 1969 with conventional telescoping-tube suspension.
Honda targeted hunters, fishermen, commuters and outdoorsmen with the Trail 90. Early ads often featured these bikes in wilderness settings, and they were well suited to narrow trails, being small, lightweight (around 188 pounds) and with a forgiving suspension. The bike was ideal for climbing and carrying packs. The four-stroke engine was quiet and almost all models were equipped with spark-arrestor exhausts.
While targeted at off-road users, this was not a dirt bike in the conventional sense. They could be registered for road use, and had a top speed in hi-ratio road gear of around 55 mph (89 km/h). Fuel economy was excellent, often around and above 100mpg. In local commuter traffic, they were extremely maneuverable, though they were poorly-suited for highway travel due to limited power, off-road-biased tires, and top speed.
The CT90 ended production in 1979, replaced the following year by the CT110, which was essentially the same machine bored out to 105cc and weighing slightly more. The 1980 CT110 lacked the reduction box; however, it returned in following years.