Available from November 2023
| Engine type | Liquid-cooled, 4-stroke Single |
| Displacement | 249 cm3 |
| Bore x stroke | 78.0 x 52.2 mm |
| Compression ratio | 14.1:1 |
| Valve/Induction system | DOHC, 4 valves |
| Fuel system | Fuel injection: O 43 mm x 1 (Keihin) with dual injection |
| Ignition | Digital DC-CDI |
| Starting | Electric |
| Lubrication | Forced lubrication, semi-dry sump |
| Transmission | 5-speed |
| Final Drive | Chain |
| Primary reduction ratio | 3.350 (67/20) |
| Gear ratios: 1st | 2.154 (28/13) |
| Gear ratios: 2nd | 1.733 (26/15) |
| Gear ratios: 3rd | 1.438 (23/16) |
| Gear ratios: 4th | 1.235 (21/17) |
| Gear ratios: 5th | 1.045 (23/22) |
| Clutch | Wet multi-disc, manual |
| Final reduction ratio | 3.846 (50/13) |
| Rake/Trail | 118 mm |
| Wheel travel - front | 314 mm |
| Wheel travel - rear | 316 mm |
| Tyre - front | 80/100-21 51M |
| Tyre - rear | 100/90-19 57M |
| Steering angle - left / right | 42o / 42o |
| Frame type | Perimeter, aluminium |
| Suspension - front | 48 mm inverted telescopic Separate Function front Fork (SFF) Type 2. Compression damping: 22-way. Rebound damping: 20-way. Spring preload: 40-way |
| Suspension - rear | New Uni Trak with adjustable dual-range (high/lowspeed) compression damping, adjustable rebound damping and adjustable preload |
| Brakes - front | Single semi-floating 270 mm petal disc. Caliper: Dual-piston |
| Brakes - rear | Single 240 mm petal disc. Caliper: Single-piston |
| Dimensions (L x W x H) | 2,190 x 820 x 1,270 mm |
| Wheelbase | 1,485 mm |
| Ground Clearance | 345 mm |
| Seat height | 960 mm |
| Fuel capacity | 6.2 litres |
| Curb Mass | 108 kg |
Additional engine updates increase peak power of the already powerful engine by approximately 1.0 kW (1.4 PS). Rev limit increases a further 350 min-1.
Updated suspension settings contribute to increased bump absorption and traction, while minor brake component revisions enhance controllability.
Dunlop MX33 tyres offer increased traction to match the engine’s increased power. A wider 110/90-19 rear tyre contributes to increased rear wheel traction as well as a greater planted feeling.
The footpegs are 5 mm wider (front-to-rear) and positioned 3 mm rearward to offer excellent grip, superb feel making it easier to weight the pegs plus they are lighter too.
Electric start makes restarting the engine as easy as pushing a button.
Like the KX450, a hydraulic clutch offers more direct feel and lighter lever action. Less play as the clutch heats up during heavy use results in more consistent feeling.
Factory-style ø28.6 mm Renthal aluminium Fatbar, a popular aftermarket part, is now a standard feature. The thicker handlebar helps reduce vibration and shocks transmitted to the rider, while the new grip position (19 mm lower, 8 mm closer) helps put the rider in a position that makes it easier to weight the front wheel.
All-new KX450-style bodywork features long, smooth surfaces and a flatter tank-seat line designed to facilitate rider movement and control.
KX450-based frame (an evolution of the current design) and KX450 swingarm offer improved handling and increased rear wheel traction.
