2002 KTM 250SX
General Specifications
| Model | KTM 250 SX |
| Year | 2002 |
| Category | Motocross |
| Engine Type | Single-cylinder, 2-stroke |
| Weight | Approximately 101 kg dry |
Engine
| Displacement | 249 cc |
| Bore x Stroke | 66.4 x 72 mm |
| Compression Ratio | |
| Fuel System | Keihin PWK 38 carburettor | Replacement Options |
| Ignition | Kokusan electronic CDI |
| Spark Plug | NGK BR8ECM |
| Spark Plug Gap | 0.6 mm |
| Cooling System | Liquid cooled |
| Starting System | Kick starter |
Transmission
| Transmission | 5-speed manual |
| Clutch | Wet multi-disc clutch, Magura hydraulic operation |
| Final Drive | Chain |
Dimensions
| Overall Length | |
| Overall Width | |
| Overall Height | |
| Wheelbase | Approximately 1481 mm |
| Ground Clearance | |
| Seat Height | |
| Fuel Capacity | Approximately 7.5 litres |
Chassis
Suspension
| Front Suspension | WP 43 mm upside-down telescopic fork | Fork Oil Levels |
| Front Suspension Travel | 295 mm |
| Rear Suspension | WP PDS monoshock, linkage-less |
| Rear Suspension Travel | Approximately 320 mm wheel travel |
| Fork Oil | SAE 5 fork oil; 120 mm oil level |
Brakes & Wheels
| Front Brake | Brembo hydraulic single disc |
| Rear Brake | Brembo hydraulic single disc |
| Front Wheel Size | 21 inch |
| Rear Wheel Size | 19 inch |
Service Data
| Fuel Type | Premium unleaded petrol with 2-stroke oil premix |
| Premix Information | High-quality 2-stroke motorcycle oil mixed with petrol | Premix Calculator |
| Gearbox Oil | 0.8 litre SAE 15W-50 |
| Air Filter | Washable oiled foam element |
| Service Notes | Competition maintenance schedule. Clean and re-oil the foam air filter frequently, especially in dusty conditions. Replace gearbox oil regularly and inspect the piston, rings, small-end bearing and TVC exhaust power-valve system at appropriate racing service intervals. |
2002 KTM 250 SX – Refining KTM's Two-Stroke Contender
The 2002 KTM 250 SX was primarily an evolutionary development of the previous year's machine rather than an all-new generation. By this stage KTM had established the basic formula that made its 250 two-stroke distinctive: a powerful 249 cc engine, quality European components, hydraulic clutch and the unusual linkage-less PDS rear suspension system.
Its liquid-cooled two-stroke engine retained the 66.4 x 72 mm bore and stroke and breathed through a 38 mm Keihin PWK carburettor. The engine used KTM's exhaust power-valve system to make the hard-hitting 250 more usable across the rev range. Owners restoring an original machine should pay particular attention to carburettor wear, jetting and accumulated deposits in the power-valve mechanism. MXOwners' carburettor information and replacement options can be useful when the original PWK needs attention.
The chassis continued KTM's chrome-moly steel construction and WP suspension package. A 43 mm WP upside-down fork provided 295 mm of travel, while the rear used the WP PDS shock mounted directly between frame and swingarm without a conventional linkage. Correct suspension servicing and setup are important on these older KTMs, and owners rebuilding the front end can consult the fork oil reference information.
Other typically premium KTM equipment included Brembo hydraulic disc brakes and a Magura hydraulic clutch. Combined with a dry weight of roughly 101 kg, the result was a serious open-class motocross machine with a noticeably different character from the Japanese 250 two-strokes of the period.
Today the 2002 250 SX remains an appealing early-2000s KTM because it combines strong two-stroke performance with relatively straightforward mechanical construction. A healthy top end, clean power valve, correctly serviced WP suspension, fresh gearbox oil and properly maintained foam air filter are the foundations of a good example. Owners replacing ageing rubber can also check the motocross tyre size guide when selecting modern tyres for the original 21-inch front and 19-inch rear wheels.
