| 2003 KLX400R SPECIFICATIONS | |
| Engine | 4-stroke, DOHC, 4-valve single |
| Displacement | 398cc |
| Bore x Stroke | 90.0mm x 62.6mm |
| Compression ratio | 12.2:1 |
| Cooling | Liquid |
| Carburetion | Keihin FCR39 |
| Ignition | Digital CDI |
| Transmission | 5-speed |
| Frame | High-tensile steel |
| Rake/Trail | n/a |
| Suspension type, front | 49mm conventional cartridge fork |
| Suspension adjustments, front | 14-way compression damping, 18-way rebound damping |
| Suspension, rear | single shock system |
| Suspension adjustments, rear | 20-way compression and 18-way rebound damping adjustment |
| Wheel travel, front | 11.3 in. |
| Wheel travel, rear | 11.6 in. |
| Tire, front | 80/100 x 21 |
| Tire, rear | 110/100 x 18 |
| Brakes, front/rear | Hydraulic disc/Disc |
| Overall length | 88.0 in. |
| Overall width | 32.5 in. |
| Overall height | 49.0 in. |
| Seat height | 37.2 in. |
| Wheelbase | 58.0 in. |
| Ground clearance | 12.8 in. |
| Fuel capacity | 2.6 gal. |
| Dry weight | 262 lbs. |