249 cm3 liquid-cooled, 4-stroke Single with DOHC 4-valve head pumps out a wide spread of power.

Claimed power - 43hp (31.6kw) @ 11,000rpm

Claimed torque - 28.7 N-m (2.93kgf-m) @ 8,500rpm

Very oversquare bore/stroke ratio of 77.0 x 53.6 mm ensures high reliability at high rpm. Rev limiter prevents over-revving.

Forged 2-ring piston is tin plated to reduce wear and the piston skirts have microscopic grooves to ensure oil retention and low friction.

Billet camshafts are carburised for durability and operate alloy tool steel tappets. Cam profiles designed for wide power band and high peak power.

Lightweight titanium valves (IN: 31 mm; EX: 25 mm) for high-rpm reliability. Oxidising treatment to valves reduces wear.

37 mm Keihin FCR flat-slide carburettor is equipped with TPS. Accelerator pump contributes to quick throttle response. Handle grip and throttle cables changed to suit the push-pull style carb.

Reed valve located between the crankcase and the transmission case reduces pumping loss for high output and quick response.

Oil pump uses a 29 x 4 mm feed rotor and a 29 x 10 mm scavenge rotor.

Semi-dry-sump design keeps oil away from the crankshaft to reduce windage loss and contributes to a lower centre of gravity and reduced weight.

Oil feed to top end is internal, via the bolt passageways. This design eliminates the weight and complexity of external oil lines.

One-piece water pump/oil filter cover saves weight and adds to compactness.

The shaft on which the kick-start idler gear spins also functions as a crankcase breather. Holes in the shaft and gear create a centrifugal breather that evacuates air from the transmission cavity.

AC-CDI ignition uses TPS (Throttle Position Sensor) and a 3D ignition map to provide ideal ignition timing for various engine conditions. During acceleration and deceleration, the system makes adjustments to the 3D ignition map, resulting in improved acceleration performance and smooth engine braking.

Quick-shifting 5-speed transmission uses a ratchet shift mechanism for a light shift touch. The ratchet mechanism uses a “phased” shift holder to compensate for the different shift effort riders tend to use when up-shifting and down-shifting.

Optional rotors will be available to allow riders to alter the amount of engine inertia to suit riding style and track conditions.

Transmission gears are made of tough DSG-2 (Daido Super Steel for Gears #2).

Lightweight exhaust system features a titanium exhaust pipe “stepped” to a slightly larger diameter stainless steel pipe. Lightweight silencer has aluminium body and stainless steel interior. End cap resists mud plugging.

Automatic centrifugal decompression system fitted to exhaust cam lifts one exhaust valve to ease starting.

A hot start system gives quick starts when the engine is hot. The hot start lever is unitised with the clutch lever.

An optional cable set-up will allow manual operation of the decompressor (via a lever on the right handle grip). This makes it easier to clear a “flooded” engine.

“Metafoam” gaskets used to ease maintenance chores.