2025 Triumph TF 250-X
General Specifications
| Model | Triumph TF 250-X |
| Year | 2025 |
| Category | Motocross |
| Engine Type | Single-cylinder, liquid-cooled, DOHC, 4-valve, 4-stroke engine |
| Weight | 104 kg wet (manufacturer specification) |
Engine
| Displacement | 249.95 cc |
| Bore x Stroke | 78.0 x 52.3 mm |
| Compression Ratio | 14.4:1 |
| Fuel System | Dell'Orto electronic fuel injection throttle body with Athena engine management system |
| Ignition | ECU-controlled electronic ignition with Athena EMS and updated 2025 fuel mapping |
| Spark Plug | NGK LMAR9AI-8 |
| Spark Plug Gap | 0.8 mm |
| Cooling System | Liquid-cooled, radiator system with mechanically driven coolant pump; Triumph D2053 OAT premixed coolant, 2.4-litre system capacity |
| Starting System | Electric start |
Transmission
| Transmission | 5-speed manual gearbox |
| Clutch | Wet multi-plate clutch with Belleville spring |
| Final Drive | Chain drive, 13-tooth front sprocket and 48-tooth rear sprocket; 114-link chain listed in parts data |
Dimensions
| Overall Length | |
| Overall Width | 836 mm across handlebars |
| Overall Height | 1270 mm |
| Wheelbase | 1492 mm |
| Ground Clearance | |
| Seat Height | 960 mm |
| Fuel Capacity | 7.0 litres |
Chassis
| Frame | Lightweight aluminium spine and double-cradle frame with fabricated aluminium swingarm |
| Front Tyre | 80/100-21 Pirelli Scorpion MX32 Mid Soft | Tyre Size Guide |
| Rear Tyre | 100/90-19 Pirelli Scorpion MX32 Mid Soft | Tyre Size Guide |
Suspension
| Front Suspension | 48 mm KYB Air-Oil Separate (AOS) inverted coil-spring forks with adjustable compression and rebound damping | Fork Oil Levels |
| Front Suspension Travel | 310 mm |
| Rear Suspension | KYB piggyback coil-spring monoshock with linkage, adjustable high-speed and low-speed compression damping and rebound damping |
| Rear Suspension Travel | 305 mm |
| Fork Oil | KYB AOS-compatible suspension fork oil. KYB 01M is a commonly available KYB fork lubricant; confirm the exact approved fluid, inner-cartridge quantity and outer-chamber oil volume against the Triumph service manual. The owner handbook specifies adjusting fork oil volume in 5 ml increments when tuning. |
Brakes & Wheels
| Front Brake | 260 mm Galfer disc with Brembo floating caliper and twin 24 mm pistons |
| Rear Brake | 220 mm Galfer disc with Brembo floating caliper and single 26 mm piston |
| Front Wheel Size | 21 x 1.60 inch DirtStar 7000 Series aluminium spoked rim |
| Rear Wheel Size | 19 x 1.85 inch DirtStar 7000 Series aluminium spoked rim |
Service Data
| Fuel Type | Unleaded petrol meeting the minimum octane and fuel-quality requirements specified in the Triumph owner's handbook |
| Premix Information | Not applicable. Four-stroke engine with pressure-fed engine lubrication. Do not mix two-stroke oil into the petrol. |
| Gearbox Oil | SAE 10W-50 fully synthetic motorcycle engine oil meeting API SN or higher and JASO MA2. Engine and gearbox use a common lubrication system. Oil capacity: 0.85 litres without filter replacement, 0.95 litres with filter replacement and 1.0 litre dry fill. |
| Air Filter | Washable, reusable oiled foam air-filter element |
| Service Notes | The 2025 Triumph TF 250-X is the second model year of Triumph's purpose-built four-stroke motocross motorcycle. The 2025 model retains the original 249.95cc DOHC engine and lightweight aluminium chassis while receiving revised ECU fuel mapping for more consistent power delivery across operating temperatures and updated graphics. The engine features a forged aluminium piston, titanium valves and advanced internal coatings. Manufacturer specifications include 48 mm KYB AOS forks with 310 mm travel, KYB rear shock with 305 mm travel, Brembo brakes and Pirelli Scorpion MX32 tyres. Spark plug NGK LMAR9AI-8 with a 0.8 mm gap is listed for the 2025 model in specialist parts data; confirm against the factory handbook before replacement. Triumph specifies SAE 10W-50 fully synthetic motorcycle engine oil meeting API SN or higher and JASO MA2. Oil refill quantity is 0.95 litres when replacing the oil filter. The cooling system holds approximately 2.4 litres of specified premixed coolant. Maintain the air filter, engine oil, oil filter, valve clearances, cooling system, chain and suspension linkage according to Triumph's competition maintenance schedule. Follow the factory service manual for KYB fork oil specifications and exact service quantities. |
2025 Triumph TF 250-X – Refining Britain's New Motocross Contender
The 2025 Triumph TF 250-X represents the second year of the British manufacturer's return to serious off-road competition machinery. Following the introduction of the TF 250-X for 2024, Triumph entered the highly competitive 250cc four-stroke motocross category with a purpose-built engine, lightweight aluminium frame and premium racing components. Developed with input from motocross legend Ricky Carmichael and enduro champion Iván Cervantes, the motorcycle marked an important expansion beyond Triumph's established road motorcycle heritage.
For 2025, Triumph concentrated on refinement rather than introducing an entirely new generation. The principal technical change was revised electronic fuel mapping, designed to improve the consistency of fuel delivery and throttle response across different engine temperatures and operating conditions. Updated graphics also distinguish the second-year motorcycle from its predecessor. The basic engine, five-speed transmission and aluminium chassis remain substantially unchanged.
The 249.95cc liquid-cooled four-stroke engine features dual overhead camshafts, four valves, a 14.4:1 compression ratio and electronic fuel injection controlled by an Athena engine-management system. A forged aluminium piston and titanium valves reflect its competition-focused construction. Owners looking for replacement components can consult the MXOwners motorcycle parts finder when researching service and repair options.
The TF 250-X also stands out for its suspension and braking equipment. KYB 48 mm AOS coil-spring forks provide 310 mm of front travel, while the linkage-operated KYB rear shock offers 305 mm of travel with adjustable high-speed and low-speed compression damping. Brembo braking components and Pirelli Scorpion MX32 tyres complete the standard package. Correct rider sag, spring preload and damping adjustments are important for achieving balanced handling, and the MXOwners rear suspension setup guide provides useful information about these adjustments.
Routine maintenance is particularly important on a high-revving competition four-stroke. Triumph specifies fully synthetic SAE 10W-50 engine oil meeting API SN or higher and JASO MA2 standards, with approximately 0.95 litres required when replacing the oil filter. Regular attention to the foam air filter, valve clearances, cooling system and suspension components remains essential. With improved fuel mapping and the same race-oriented mechanical package introduced in 2024, the 2025 TF 250-X continues Triumph's effort to establish itself in modern motocross competition.
