1980 Kawasaki KX420 Specifications and Specs
Specifications and workshop reference information for the 1980 Kawasaki KX420, including engine, chassis, service data and setup details.
Note: Specs are compiled from factory data, manuals and owner feedback. Bikes vary — if yours is different, jump into the forum and share it.
General Specifications
| Engine Type | 2-stroke, single-cylinder, reed valve |
| Displacement | 422 cc |
| Bore × Stroke | 83 × 78 mm |
| Maximum Torque | 6.91 kg-m (36.2 ft-lb) |
| Maximum Power | 50 kg-m @ 6000 rpm |
| Carburetor | Mikuni VM38SS |
| Fuel Type | Petrol mix (20:1) |
| Lubrication | Premix |
| Starting System | Primary kick |
| Ignition | CDI |
| Ignition Timing | 18° BTDC @ 6000 rpm |
| Spark Plug | NGK B9EV |
| Compression Pressure | 17 psi (12.0 kg/cm²) |
Port Timing
| Scavenging | 59.5° |
| Exhaust Open/Close | 92° |
Transmission
| Transmission Type | 5-speed constant mesh |
| Clutch | Wet, multi-disc |
| 1st Gear | 2.000 (32/16) |
| 2nd Gear | 1.454 (32/22) |
| 3rd Gear | 1.143 (26/22) |
| 4th Gear | 0.954 (21/22) |
| 5th Gear | 0.791 (19/24) |
| Primary Reduction | 2.500 (65/26) |
| Final Reduction | 3.571 (50/14) |
| Overall Drive Ratio | 7.062 (Top gear) |
| Transmission Oil | 10W30, 10W40 |
| Transmission Oil Capacity | 1.0 L (1.1 US qt) |
Dimensions
| Overall Length | 2230 mm (87.8 in) |
| Overall Width | 840 mm (33.1 in) |
| Overall Height | 1200 mm (47.2 in) |
| Wheelbase | 1520 mm (59.8 in) |
| Ground Clearance | 355 mm (13.9 in) |
| Dry Weight | 105 kg (231 lb) |
| Fuel Tank Capacity | 9.8 L (2.4 US gal) |
| Seat Height | 985 mm (38.8 in) |
Chassis
| Frame Type | Tubular, single down tube |
| Steering Angle | 45° |
| Caster | 62° |
| Trail | 120 mm |
| Front Tire | 3.00-21 |
| Rear Tire | 5.10-18 |
Suspension
| Front | Telescopic fork |
| Rear | Uni-Trak swingarm |
| Front Suspension Travel | 300 mm |
| Rear Wheel Travel | 300 mm |
| Fork Oil | 426 cc (10W20) |
| Fork Air Pressure | 0.3 kg/cm² (4.3 psi) |
Brakes & Wheels
| Front Brake | Drum brake |
| Rear Brake | Drum brake |
| Front Drum Size | 140 × 28 mm |
| Rear Drum Size | 150 × 28 mm |
420cc Other Specs
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