ENGINE / DRIVETRAIN
For 2023, the Trail125 gets the 124cc air-cooled, two-valve, overhead-camshaft, four-stroke, single-cylinder engine that the Super Cub received in 2022. Efficient, quiet, fuel-efficient and durable, the engine combines the bottom end (with redesigned crankcases) from the Japanese-market C110 with the SOHC, two-valve top end of the Grom. The engine produces useable, enjoyable power all the way through the rev range, while still offering impressive fuel economy.
Compared to its predecessor, the 2023 Trail125 is more undersquare, with a 50.0mm bore and a 63.1mm stroke, and compression ratio is 10.0:1. State-of-the-art programmed fuel injection (PGM-FI) has automatic enrichment and electronic ignition, ensuring trouble-free starting and efficient operation in every conceivable condition.
Compared to the Super Cub, the Trail125 has a longer intake and tuned exhaust for enhanced low- and midrange power, as well as a three-tooth-larger rear sprocket (38 teeth) for lower gearing—all changes that are ideal for trekking and touring on forest-service roads and trails. The airbox is designed to match the engine. It smooths airflow on the clean side of the panel-type, wet-paper filter (which has a 10,000-mile life in normal riding conditions) and—along with the connecting tube and injector position—improves driveability. Many Trail125 owners prefer to do their own maintenance, and a welcome feature is a replaceable oil filter.
While the outward appearance of the muffler (one element of the Trail125’s “mythology”) stays the same, the internals are modernized; with the gain in combustion efficiency, a single, more efficient catalyzer replaces the pair of catalyzers used with the previous exhaust. The ECU programming maximizes performance and efficiency, and the alternator output has been increased.
As before, the transmission has four speeds (with neutral at the bottom), and in true Trail125 tradition, it’s operated via an automatic centrifugal clutch, eliminating the need for a clutch lever. At standstill, the rider simply selects the gear required with the left foot lever; as the throttle is opened, the clutch operates automatically, and it continues to do so through each ratio change, up or down. A helical primary gear reduces mechanical noise. For optimum shift feel and reduced shift noise, the engine has a high-quality shift-drum bearing, shift-arm rubber, and optimized clutch-damper rubber material.
