2013 KTM 250 SX‑F

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The main upgrade made for the 2013 version of the KTM 250 SX-F is its engine which comes with a completely new design, without kickstarter, in a new case, manufactured in a die-casting process. All these tweaks were made to keep the weight to as low as possible.

The engine wasn’t the only part that received attention from KTM’s engineers, as the body has also received a few modifications. Most of upgrades were made o improve the overall ergonomics and the company says that the “function of the plastics have been designed in such a way that the whole chassis and engine package forms a perfect harmony with the rider down to the very last detail.”

Among the design modifications made for the 2013 model you’ll find a restyled fuel tank and spoiler and a fresh airbox cover and front fender.

Hit the jump for more information on the 2013 KTM 250 SX‑F.

OVERVIEW

KTM 250 SX‑F

The KTM 250 SX‑F has been an established force in the MX2 World Championship for 8 years now. And the new generation appears with a completely new, even lighter engine and an updated injection system. In other words: a performance package that will redefine the MX2 class. Together with a new frame and new bodywork, the new KTM 250 SX‑F 2013 is a winning bike that dominates the MX2 class.

FORK

The further improved 48 mm upside-down fork featuring closed-cartridge technology has been optimised with completely revamped settings for perfect harmony with the new frame and engine. The new oil is significantly more wear-resistant and guarantees more consistent damping throughout both the course of a race and the bike’s life cycle. A new lower triple clamp is 80 g lighter and, just like the upper triple clamp, CNC-machined from high quality aluminium, whereby the steering characteristics and hence the responsiveness of the fork have been noticeably improved.

SHOCK ABSORBER

The WP monoshock has been further refined for 2013 and, together with the KTM linkage system, it excels with its completely revamped settings for improved damping, more traction and even higher reserves against bottoming out. As ever, rebound and compression damping (high and low speed) can be adapted individually to the track and rider in no time at all.

WHEELS

The wheels are fitted with lightweight, CNC-machined hubs and high-end EXCEL rims, plus new, black-coated spokes with aluminium nipples, guaranteeing the highest levels of stability while keeping weight to a minimum. The Pirelli Scorpion tyres (MX Mid Soft 32) stand for excellent traction and good performance. For the benefit of greater ride stability on the KTM 250 SX‑F, the rear axle has been increased in diameter from 20 mm to 25 mm.

BODYWORK

KTM 250 SX‑F

Not only visually does the completely revamped bodywork indicate that the 2013 model year represents a new SX generation. Above all, the ergonomics and function of the plastics have been designed in such a way that the whole chassis and engine package forms a perfect harmony with the rider down to the very last detail. The fuel tank and spoiler have been restyled along with the airbox cover and the front fender, including the start number plate. A particular highlight is the new front fender, which has no ribbing whatsoever on the inside, thereby preventing mud build-up. A pioneering structure and improved attachment of the fender to the triple clamp result in up to 50% greater lateral stiffness.

ENGINE

A completely new design, without kickstarter, in a new engine case, manufactured in a die-casting process. What’s all this for? To save weight. A new, elastic and simultaneously high-strength, aluminium alloy provides additional damage protection for the engine on the KTM 250 SX‑F 2013.

CYLINDER + PISTON

The stroke-bore ratio of the KTM 250 SX‑F 2013 has been defined as somewhat shorter-stroked for the benefit of higher peak power, with the new cylinder now boasting a bore of 78 mm (previously 76 mm), hence providing space for larger valves. Despite the larger diameter, the box-type, forged piston is lighter in weight. This reduces the moving masses and enables higher engine speeds as well as more power.

BALANCER SHAFT

KTM 250 SX‑F

The goal was less vibration in spite of increased revs. That’s why the new KTM 250 SX-F engine also has a laterally positioned balancer shaft, which also serves as the drive wheel for the timing chain and the water pump.

NEW INJECTION SYSTEM

The Keihin engine management system with electronic fuel injection has been improved significantly on the KTM 250 SX‑F 2013. Even more performance has been achieved with greater air flow through a new throttle body - featuring a 44 mm instead of a 42 mm port - in conjunction with the new injector nozzle. The throttle position sensor (TPS) is harder wearing and protected from stone impact with a plastic protector. The connectors are now enclosed in rubber grommets to protect them from steam-jet pressure. The wiring harness has been simplified and the quality of cables and connectors optimised. Additional engine characteristics can also still be activated with an optional map-select switch on the handlebars.

CYLINDER HEAD

Those wanting to know what drives a winner to victory will find the answer here. The heart of the newly developed DOHC engine is the redesigned cylinder head with twin overhead camshafts and DLC-coated cam followers that actuate the titanium valves. Larger, flow-optimised ducts in conjunction with the more generously dimensioned intake valves (intake 32.5 mm, exhaust 26.5 mm) guarantee 10% more gas flow and therefore significantly improved performance. The new camshafts on the 250 SX‑F 2013 have also been designed (new valve timing, larger stroke) for achieving a huge increase in performance compared with the predecessor model, above all at the top end of the rev range (max. 14,000 1/min, previously 13,400 1/min).

SPECIFICATIONS

KTM 250 SX‑F
Engine DesignSingle-cylinder, 4-stroke, spark-ignition engine, liquid-cooled
Displacement249.91 cm³
Bore78 mm
Stroke52.3 mm
Starting aidElectric starter
Engine lubricationForced oil lubrication with 2 Eaton pumps
Primary gear ratio22:68
Final drive13:48
Cooling systemLiquid cooling system, continuous circulation of cooling liquid with water pump
ClutchWet multi-disc clutch / hydraulically operated
Ignition systemContactless, controlled, fully electronic ignition system with digital ignition timing adjustment
FrameCentral tube frame made of chrome molybdenum steel tubing
ForksWP Suspension Up Side Down 4860 MXMA CC
Shock absorberWP Suspension 5018 BAVP DCC
Suspension travel Front300 mm
Suspension travel Rear330 mm
Brake systemDisc brakes, brake calipers on floating bearings
Brake discs - diameter Front260 mm
Brake discs - diameter Rear220 mm
Chain5/8 x 1/4"
Steering head angle63.5°
Wheel base1,495±10 mm
Ground clearance (unloaded)375 mm
Seat height (unloaded)992 mm
Total fuel tank capacity approx.7.5 l Unleaded premium fuel (95 RON)
Weight without fuel approx.102.8 kg

QUOTES

KTM 250 SX‑F

Dirtrider ---- "In short, some of the changes here include a shorter stroke, larger bore, a new cylinder head layout and a higher rpm range. The new 2013 also has larger ports, a bettered combustion chamber, larger intake valves and new camshafts. On the dyno, KTM claims a power increase of five horsepower. Harnessing all of this extra power are completely new engine cases that are made in a high-pressure die cast instead of a sand cast. This process allows the cases to be of a thinner wall thickness saving tons of weight."

Motocross ---- "Aesthetically, as always, the bike is appealing and attractive. Brakes and clutch are quality and, to me, even the lines on the bike are better this year. I can do without the soft foam feeling from the seat but then again I am a test rider and can get picky from time to time. KTM looks to be back in the shootout game this year with this all-new 2013 250 SX-F. I am looking forward to getting on a variety of tracks and really breaking down the nooks and crannies of the orange little 4 banger!"

Motorcycle-usa ---- "The 2013 KTM 250 SX-F is by far the best it has ever been and our team responded by giving it a second place finish in our 2013 250 motocross shootout. A strong engine, ridiculous brakes and electric start make the KTM a desirable bike to race or own. With some work to the suspension it could be even better, but we are impressed with the new Katoom and not surprised with its runner-up status."


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