KTM has announced its US-bound models for 2014 and the big news focuses on one model, the 250XCF-W. It (along with all the four-stroke XC-W and EXC models) gets a new, lighter frame. What the 250XCF-W alone gets, is an all-new engine. The DOHC motor has larger intake valves to match a larger piston. Yes, the piston diameter has increased 2.0mm, and the stroke has decreased 2.7mm. KTM claims a 10% increase in intake flow rate, and that piston that has grown in diameter has actually gotten lighter, which KTM claims results in quicker response. The bike also gets the DDS clutch and looks to be the leader in the orange brigade as far as changed models.
All the KTM model lines gets updates and tweaks worthy of calling themselves new models, but nothing as radical as the 250XCF-W’s makeover. One interesting changed mentioned by KTM on the 450 SX-F is the “North American R&D re-tuned suspension” – so they’ve been playing with the handling and suspension action of the four-stroke motocrosser. Other refinements to the four-stroke MXers are a new front brake, chain guide, and silencer.
Two-stroke racers shouldn’t feel left out, the MX smokers got some engine tweaks, including a new Boyesen intake on all the big bikes, a new shape to the 125s piston, and a new cylinder head, and ignition mapping for the 250SX.
THE FOLLOWING INFORMATION IS STRAIGHT FROM KTM’S ANNOUNCEMENT OF THE NEW MODELS:
XC-W/EXC MODEL 2014 NEWS
Only two years after the launch of the new offroad generation (the revolutionary 350 XCF-W flagship), KTM has again revised the complete Enduro Competition range for 2014. Headlining the changes is the all-new engine for the 250 XCF-W, as well as lighter frame and swingarm development, refined suspension setups and new ergonomically enhanced bodywork for all XC-W/EXC models. KTM enters 2014 with a markedly improved range of high-tech 2- and 4-stroke models, setting a substantially higher benchmark for the Enduro world.
• Lighter frames for the 4-stroke models
• New lower triple clamp
• Suspension set up of the 250/300 XC-W and 250 XCF-W models optimized
• New 250cc 4-stroke engine for the 250 XCF-W
• New ECU for the 250 XCF-W
• Revised exhaust system for the 250 XCF-W
• Revised bodywork
• New headlight
• New colors and graphics
• 250 XCF-W and 250/300 XC-W now even more powerful and agile
• Less weight for the 4-stroke models
• Optimized ergonomics and contact areas
• Brighter headlight
<strong>2014 KTM 250 XCF-W</strong>
For 2014, the lively 250 4-stroke receives a completely new DOHC engine distinguished mainly by significantly more torque than its predecessor. The new power plant, the optimized frame and the new bodywork make the 250 XCF-W a winner’s bike bound to define the new benchmark of its class.
For 2014, the KTM engineers lit up the next evolutionary stage and designed a brand new cutting-edge DOHC engine for the 250 XCF-W, combining their concentrated engine know-how from racing and development. The new generation’s construction shares many base components with the successful 350 XCF-W engine. This achieves a perceptible increase of torque up to 4 Nm between 6,000 – 7,000 rpm.
The centerpiece of the newly-developed DOHC engine is its newly- designed cylinder head with two overhead camshafts and DLC- coated followers. Compared to last year, larger, flow optimized ports in combination with larger intake valves ensure a flow rate increase of about 10 percent, which in turn means a significant performance gain. The new camshafts also have been designed in such a way as to achieve a significant power and torque increase compared to the predecessor and at the same time an Enduro specific power delivery. The engine’s optimized cooling jacket ensures better heat dissipation.
• Flow optimized ports with larger cross-section » torque increase
• Enlarged intake valve cross-sections (32.5mm instead of 30.9mm) » torque increase
• New camshafts » Enduro specific power delivery
• Optimized cooling jacket » improved cooling
For 2014, the new 250 XCF-W power pack has received a somewhat shorter stroke. The resulting larger bore allows the use of the larger intake valves. The forged bridged-box-type piston is even lighter than the previous component despite its 2.0mm larger diameter. Thanks to the 2.7mm shorter stroke and the lower oscillating masses, the new engine displays an even more dynamic power delivery.
• New cylinder with larger bore (78mm instead of 76mm) » increased area for larger valves, power increase
• Larger, lighter piston » lower vibrations, even quicker engine response
The crankshaft drives an intermediate shaft on the side which in turn drives the coolant pump and the two camshafts via the cam chain while at the same time acting as a counter balancer. A hydraulic chain tensioner ensures reliable chain tension to achieve highly precise valve timings.
The new 250 XCF-W’s crankshaft has a 5 percent heavier flywheel to achieve optimum traction. Like last season’s KTM SX-F models, it now has a plain big end bearing. The previous needle bearing is replaced by two force-fitted bearing shells that run directly on the crank pin. The necessary oil feed for this bearing is ensured by the engine’s pressure lubrication. This design increases the engine’s long-term durability, allowing to lengthen the crankshaft service interval – a customer benefit with respect to time, effort and cost.
• Shortened stroke » more dynamic engine response
• Crankshaft mass increased by 5 percent » improved traction
• Plain big end bearing » increased durability and less maintenance – crankshaft service interval extended from 105 to 135 hours
A completely new crankcase design, which is now pressure die-cast, allows to reduce the wall thicknesses significantly, compared to cases produced by gravity die-cast. A new aluminum alloy which at the same time has great tensile strength ensures a high resilience against stone- chipping and other damage.
• Pressure die-casting instead of gravity die-casting » thinner wall thicknesses » weight reduction (0.6 kg)
• New aluminum alloy » increased ductility » more resilient crankcase
• New clutch and ignition covers » matching new crankcase design
In order to balance the mass-forces, the new 250 XCF-W engine uses a multifunctional counter balance shaft which also drives the water pump and timing chain.
• Multifunctional counter balance shaft » reduced vibrations
The new 250 XCF-W engine can be started with a kickstarter as well as an electric starter. Well protected behind the cylinder, the electric starter is connected to the starter freewheel on the ignition rotor via the starter drive in the ignition cover.
• Optimized starter freewheel mechanism » increased durability and reliability
The new 250 XCF-W now also uses the proven DDS clutch (damped diaphragm steel) with a wear-free clutch basket and diaphragm spring. The basket is machined from high-tensile steel in one piece together with the primary drive gear. This process guarantees unbeatable reliability and contributes to the narrow engine width due to its compact rivet-less design. Additionally, it allows the use of thin steel linings which also contribute to compact clutch dimensions. The diaphragm spring makes it possible to implement an additional rubber damping system inside the clutch hub, guaranteeing reliability for the transmission and good traction. In addition, a stronger inner hub further increases stability. Finally, the hydraulic clutch mechanism by Brembo in conjunction with the diaphragm spring guarantees a very light operation and good controllable modulation of the clutch.
• New DDS clutch with steel basket , diaphragm spring and integrated rubber dampener » low weight, compact installation space, low operating force, gear box protection
• Clutch package specially matched to the 250 XCF-W engine » optimized modulation
• Reinforced inner hub » increased reliability
• Reworked clutch master cylinder (sand-blasted with black cover)
Specially developed for the 250 XCF-W, the new 6-speed Enduro gear box has slightly shorter gear ratios in 4th, 5th and 6th gear than the predecessor. The new transmission is distinguished by easy and precise shifting. The final drive gear ratio has been matched to the new gear box.
• Newly-designed 6-speed gear box » optimized gear ratios, precise shifting, high durability (13:32 16:30 16:24 23:28 23:23 26:22)
• Matching final drive gear ratio (13/52 instead of 13/50) » gearing matched to new transmission
ENGINE MANAGEMENT SYSTEM (EMS)
The Engine Management System by Keihin with electronic fuel injection and 42mm throttle body ensures a spontaneous response and maximum engine performance. An oil-cooled 196 W AC alternator provides sufficient energy for the fuel injection, lighting and other electrical loads. A newly-designed ECU ensures even faster and absolutely reliable data processing.
• New ECU » faster data processing, higher ignition energy
THE DIFFERENCES BETWEEN THE 2014 250 XCF-W ENGINE AND THE 2014 250 SX-F ENGINE:
• Camshafts with Enduro-specific timings and less lift
• Reduced valve spring rate
• 0.4 mm higher cylinder for reduced compression
• 6-speed gear box instead of 5-speed
• Electric starter and kickstarter vs. electric starter only with no kickstarter option
• More powerful generator
• DDS clutch (damped diaphragm steel) with diaphragm spring and hub dampener vs. CSS clutch (coil spring steel) with coil springs
• Crankshaft with heavier flywheel (35 percent heavier than SX-F)