KTM: 2011 KTM 350 SX-F Dirt Bike Motorcycle

In 2006, Stefan Everts was reigning world champion (with a mere 14 victories in 15 Grand Prix) and then he became KTM Race Director.

Back then, he could already see where the future of motocross was heading and in KTM he found an ideal partner for his vision: efficient and maximum practicable performance from smaller displacements in an overall package that’s tailored unconditionally to the requirements of the rider.

2011 ktm 350 sx-f, ktm, ktm dirt bikes, ktm 350, ktm sx-f, ktm motorcycles4 years or so later, it’s ready: the new 350 SX-F. With a new engine, fuel injection system and smaller displacement, new bodywork, new chassis – in fact, a whole new concept.

What with the first Grand Prix victory and racing to the top of the overall standings in the MX1 class after only two races, maybe even the beginning of a new era in motocross …

Just to make it completely clear: When developing the new SX bikes, it wasn’t a case of making a special bike for a specific rider or a particular track.

It’s all about a unique bike for every track and every motocross rider. From works team professionals to motocross enthusiasts with no professional ambitions.

Whoever claims that’s impossible just hasn’t tried hard enough. Because efficient power development and playful handling are not a question of taste.

You have to give a revolutionary new development some time. Or so they say. We maintain the opposite: If you do your job properly, then you take your time beforehand. And only push the bike to the starting gate when it is ready.

The new KTM SX bikes took 6 out of 6 possible race wins at the opening round of this season’s World Championships. (The brand new 350 SX-F appears to have been not quite “ready” yet. It only finished second in the first Grand Prix of the new season. But then it won the next. And the next. And the …).

After 3 World Championship weekends: 9 race wins, 140 laps in the lead and the top places in the overall standings in MX1 and MX2 for riders and manufacturers. Whatever the current season still has in store, it is hard to imagine more convincing proof of the new KTM bikes’ ability to win.

The first thing you notice on all 2011 SX-F and SX models is the completely newly developed bodywork with its super-slim spoiler line. Or the numerous, practical, detailed solutions, such as the grip recesses, protected from dirt and heat, integrated into the rear fender. When you sit on the bike for the first time, you are struck by the perfect knee contact in the area of the fuel tank, airbox and lateral frame tube. What you experience on the first test lap is a whole new dimension …

The spine of the new 2011 SX-F model is formed by a completely newly developed chassis with linkage system. Choosing chrome-molybdenum steel as the frame material offers a whole string of structural advantages over aluminium: It provides more flexible design options, so no compromises need to be made when positioning the fuel tank or other components.

Moreover, chromoly is not as stiff as aluminium and it’s easier to maintain. As if that weren’t enough already, the new KTM frame is also even lighter than the lightest frames from the competition and twoand- a-half times more durable in material-murdering factory use.

DOHC Cylinder Head
Precision power unit engineering: Four titanium valves are opened by twin overhead camshafts, the 8g superlight finger followers are DLC-coated. This extremely hard carbon layer (diamond-likecarbon) minimises friction – and therefore wear – and is one of the reasons behind engine speeds of up to 13,000 rpm.

Electric Starter
A few years ago, KTM proved that an electric starter is not a matter of comfort and convenience in motocross (“comfort” really doesn’t come into it in motocross). An electric starter is simply a useful tool that makes you quicker. And for weight fetishists and traditionalists, we offer the opportunity to retrofit a kickstarter. After all, if you remove the electric starter, you do save 1,500 g.

The most important thing on the track isn’t “displacement”; it’s “lap time”. With the 350 SX-F, KTM has introduced a new displacement into the motocross world championship that, already in the first world championship races, has shown what it’s made for – for winning.

The completely newly developed 350 SX-F engine is an ultra-compact four-stroke with the latest electronic fuel injection system and an electric starter. The lightweight (27 kg), extremely short-stroke DOHC power unit with 57.5 mm stroke and 88 mm bore excels with its very broad rpm range and efficient rideability.

Engine Management System (EMS)KTM 350 SX-F Motorcycle Engine
The newly developed engine management system from Keihin with electronic fuel injection and 42 mm throttle body ensures spontaneous, powerful responsiveness and handling, along with maximum performance.

The system adapts itself automatically to different temperatures and altitudes, and is equipped with electronic cold-start enrichment. With the optional Map-Select-Switch (PowerParts), additional engine characteristics can be activated at the push of a button.

Furthermore, the User-Setting-Tool provides you with the opportunity to download detailed data from the bike via a USB interface and alter the mapping of ignition and injection individually on a PC.

Balancer Shaft
Every detail is important: The balancer shaft on the right-hand side not only effectively cancels out the inertia forces; it also serves as a drive mechanism for the timing chain and the water pump.

This intelligently designed solution makes a major contribution to the compact engine dimensions of the 350 SX-F.

Silencer
The new silencer with its voluminous appearance ensures that even future noise-limit requirements are adhered to reliably. Without the slightest compromise
in performance.

Shock & Swingarm
The new shock absorber for the 4-strokes has been tuned perfectly to the new frame concept with linkage system by the suspension specialists at WP.

Along with the rebound damping, the high- and low-speed compression damping can of course be adapted individually to every track and rider. The result: the finest possible responsiveness, outstanding traction and no end of reserves when it comes to bottoming out.

Brakes
All KTM SX models are equipped with the latest Brembo brakes as standard. Together with the lightweight Wave brake discs, the recognised benchmark in matters of application and braking performance.

Swingarm / Rear Suspension
The new generation of four-stroke SX models are equipped with a progressive linkage system specially developed for the new frame concept. The progression curve – optimised in endless test-bed and track tests – ensures that the WP monoshock keeps the rear wheel in constant contact with the ground, above all when the going really gets tough, for example, on extreme SuperCross tracks. Also part of the team: the new aluminium swingarm. Not only elegant, but also 300 g lighter and cast in a single piece.

Frame
A completely new frame concept: The profiled tubes made from lightweight chrome-molybdenum offer maximum torsional stiffness (ensuring greater ride stability) at the same time reduced longitudinal stiffness (noticeably more comfortable than “rock hard” aluminium). Simply put: It is the best we’ve ever ridden.

Cooling System
Thought through in fine detail: The cooling system, integrated into the frame without any open piping, simplifies mounting of the radiator and improves air flow under the fuel tank.

Fork
Competition Race Tech: Fully adjustable 48 mm upside-down fork with closed-cartridge technology and settings perfectly tuned to the new frame concept. The advantages of the sophisticated closed-cartridge system are well known: Unrivalled responsiveness over the entire suspension travel and noticeably more consistent damping under extreme use.

Fuel Tank
The slim SX fuel tank made from lightweight polyethylene has a capacity of 7.5 litres and, in the case of the 250 / 350 SX-F, is equipped with a compact fuel pump. The tried-and tested bayonet fuel tank cap can be opened in a flash and comes with a safety mechanism to prevent unintentional opening. The cap is unlocked simply by pressing the orange inner segment.

Airbox
Just one example of the unrivalled ease of maintenance on a KTM: Air filter replacement without tools in 15 seconds.

Wheels
The best and most expensive as standard: CNC-machined hubs and high-end EXCEL rims with new, high-strength aluminium spoke nipples and a gleaming spoke finish. Each wheel is another 200 g lighter.

Engine
Absolutely the most powerful engine in the MX2 starting field. With its free-revving and powerful motor, it is acknowledged as the benchmark in the quarter-litre four-stroke class. The new model year sees a fuel injection system, new camshafts, optimised intake port and numerous detail enhancements.

The 250 SX-F engine also continues to come equipped only with a kickstarter as standard. The new capacitor, combined with the fuel injection system, ensures that the engine can be started easily at all times and a battery can still be dispensed with. In addition, the new engine also offers the option of being retrofitted with the electric starter from the PowerParts range.

Engine Management System
The newly developed engine management system for the 250 SX-F from Keihin is equipped with all the features of the 350 SX-F, such as temperature and altitude compensation, and cold-start enrichment. The Map-Select-Switch (PowerParts) is just as much an option, as is the User-Setting-Tool for individual configuration on a PC.

Cylinder Head
The heart of the exceedingly compact 250 cc engine is the intelligently designed cylinder head with twin overhead camshafts and DLC-coated finger followers. The new cylinder head means a 10 % increased flow in the intake port, which translates to noticeably better performance. The newly developed camshafts with optimised valve timing provide for better cylinder charging and therefore a fuller torque curve.

Ignition / Alternator
The new 250 SX-F engine is equipped with a more powerful alternator that now runs in the oil bath. It supplies the power required for the newly developed fuel injection system.

Triple Clamps
The triple clamps are CNC-machined from a solid aluminium block and constitute an exclusive KTM patent. They are not only drop-dead gorgeous, they also noticeably support the sliding and bending behaviour of the fork.

When a bike is already so well-equipped as standard as a KTM, then there is nothing that you really need to bolt onto it to ride your way to the podium.
No need to splash out on “the usual” accessories, because they all come as standard. However, for individual adaptation to personal taste, you can always find something in the KTM PowerParts range. Ask your dealer for a Catalogue and visit www.ktm.com for all the latest news.

The 350 SX-F has an ultra-compact 4-stroke engine with modern electronic fuel injection and electric start. The extremely short stroke 349.7cc DOHC engine with 88mm bore and 57.5mm stroke has a wide usable speed range, top performance and easy rideability.

2011 KTM 350 SX-F – USA Specifications
MSRP: See KTM Dealer for prices

Engine

KTM Motorcycles

Engine type Single cylinder, 4-stroke
Displacement 349.7 cc
Bore x stroke 88/57.5 mm
Compression ratio 13.5:1
Starter Electric starter/12V 3 Ah
Transmission 5 gears
Carburetor Keihin EFI, throttle body 42 mm
Control 4 V/DOHC with finger followers
Lubrication Pressure lubrication with 2 oil pumps
Engine lubrication Motorex, SAE 10W50
Primary drive 24:73
Final drive 14:50
Cooling Liquid cooled
Clutch Wet multi-disc clutch, operated hydraulically
Ignition Keihin EMS

Chassis

Frame Central double-cradle-type 25CrMo4
Subframe Aluminium
Handlebar Renthal, Aluminium Ø 28/22 mm (1.10/0.87″)
Front suspension WP USD Ø 48 mm (1.89″)
Rear suspension WP-Monoshock with linkage
Suspension travel front/rear 300/330 mm
Brakes, front/rear Disc brakes 260/220 mm (10.24/8.66″)
Rims, front/rear 1.60 x 21″; 2.15 x 19″ Excel
Tires, front/rear 80/100-21″; 110/90-19″
Chain 5/8 x 1/4″
Main silencer Aluminium
Steering head angle 63.5°
Wheel base 1495±10 mm
Ground clearance (unloaded) 375 mm
Seat height 992 mm
Tank capacity approx. 7.5 liters
Weight (no fuel) approx. 103.9 kg

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3 comments to KTM: 2011 KTM 350 SX-F Dirt Bike Motorcycle

  1. Jørgen
    February 5th, 2011 at 4:41 am

    Best motocross bike i have ride.

  2. Motorcycle Advice USA
    February 7th, 2011 at 8:50 am

    What do you find on the KTM 350 SX-F Dirt Bike to be better than other Dirt Bikes?

  3. Motorcycle Advice USA
    March 9th, 2011 at 10:05 am

    Yea KTM sure has brought it to the table with the these great machines that they are introducing to the market! And when you see Mike Alessi riding good out there on the KTM 350 SX-F you know its an amazing bike!