Motocross Action Mag

FIRST LOOK! 2019 KTM 250SXF, 350SXF & 450SXF FOUR-STROKES

Date Added: 20/05/2018 17:02 by Motocross Action Mag
12pts
Description:

2019 KTM 450SXF four-stroke is even lighter than it was last year.

2019 KTM FOUR-STROKE FRAMES
All 2019 KTM SX models feature new high-tech and lightweight chromoly steel frames in various profiles including hydro-formed elements produced by WP Performance Systems with state-of-the-art robots. They feature optimized stiffness (2% stiffer longitudinally and 10% stiffer torsionally). The head stays are aluminum for all models. New frame guards improve grip and the right one is heat protector for the muffler. On the 250SXF, 350SXF and 450SXF there are brackets to mount a composite skid plate. The subframe is 900 grams (32 ounces) lighter and 40mm longer than before.

2019 BODYWORK, SEAT & AIRBOX
The all new-plastics that provide perfect ergonomics and contact points for the rider, maximum freedom of movement and improved handling. In addition, the I-beam design for the front and rear fenders are prime examples of an intelligent design, which guarantees maximum stability at lowest weight through a well thought-out structure and mounting.

A newly shaped seat provides improved ergonomics and better seat comfort. Due to newly developed silicone strips the seat cover provides better feel and grip. The seat installs with one long bolt from left side of the frame for easier removal and installation.

A new airbox has been completely reworked for increased. This improves throttle response. The 250SXF, 350SXF and 450SXF get new intake snorkels for improved engine performance. The large Twin-Air air filter is mounted on a stiff cage, which minimizes incorrect installation of the filter and cage. The filter can be changed without tools in seconds, a standard, original feature by KTM

2019 FUEL TANK
The 250SXF, 350SXF and 450SXF models are fitted with newly designed lightweight polyethylene tanks that improved ergonomics. Fuel capacity 1.85 gallons of fuel. The filler cap with an inside thread makes for easy and reliable closure. On the 250SXF, 350SXF and 450SXF the fuel pump hoses are routed in a straight line from the right side of the gas tank to the left-side-mounted fuel pump to eliminate kinking.

The 2019 KTM 450SXF gets a new seat, enlarged airbox, narrower ergos and more power.

2019 KTM 250SXF, 350SXF AND 450SXF EXHAUSTS
The new exhausts are slimmer and well within the sound limits for racing. The 250SXF, 350SXF and 450SXF four-strokes are fitted with new, model-specific head pipes with an advanced Flow Design Header (FDH). The resonator, which was only offered on the 450 last year, is better integrated into the pipe, making the front part of the exhaust slimmer and providing better engine performance and reduced noise. The four-stroke mufflers feature a new canister profile and end cap as well as a reworked internal design. Best of all, there is a slip-fit split between head pipe and mid-pipe that allows the exhaust system to be removed with having to remove the shock first.

2019 COOLING SYSTEM
All 2019 KTM model feature newly designed radiators which are mounted 12mm lower than the predecessors. This lowers the center of gravity and in conjunction with a new radiator shape they match perfectly with the design of the new radiator shroud to make the bike narrower and easier to get forward on the bike. Thanks to calculated liquid circulation (CFD) and improved air ventilation cooling is improved. The coolant tube, that passes through the frame, is 4 mm larger to improve coolant flow from the cylinder head to the radiators.

Hydrauiic clutch, electric starting, super shifting and the light weight make the 2019 KTM 450SXF the bike to beat in 2019.

2019 450SXF ENGINE
With its SOHC (single overhead camshaft) engine and compact cylinder head the 2019 KTM 450SXF engine is at the head of its class. Engine weight has been reduced to 59.5 pounds (with electric starter included). The compression ratio is 12.75:1. The 450SXF’s cylinder head is 15mm lower and 500 grams (17 ounces) lighter than last year. The gas flow through the newly shaped ports is controlled by a newly configured camshaft with improved cam surface and a shorter valve timing. The four-valve engine uses ultra-lightweight titanium valves (intake 40mm, exhaust 33mm), extremely rigid rocker arms and a low-friction cam chain guide

The 2019 450SXF uses a KTM-developed DDS clutch (damped diaphragm steel) with a wear-free steel basket and extremely heat resistant clutch plates. This design employs a diaphragm spring (Belleville washer) instead of the usual coil springs, which makes for a considerably easier clutch action. The diaphragm spring also leaves sufficient space for a rubber damping system integrated into the clutch hub, which benefits for both traction and durability.

Formula 1 supplier Pankl now makes the five-speed transmissions on the 2019 KTMs. All four-stroke engines are fitted with a gear sensor giving the option of different engine characteristics for each gear.

The Keihin Engine Management System, with electronic fuel injection, features a new 44mm throttle body, reworked throttle cable mount, and improved seal of the Manifold-Absolute-Pressure (MAP) sensor makes the system even more reliable. The ECU features new maps adapted to the new exhaust and cylinder head and it regulates the unique traction and launch control. In addition it provides different maps for optimal power characteristics for each gear.

Note the newly designed resonance chamber on the 2019 KTM 350SXF engine.

2019 350SXF ENGINE
The 2019 KTM 350SXF engine features a new clutch, improved transmission and a re-designed DOHC cylinder head. The reworked cylinder head design is 200 grams lighter than last year. The two overhead camshafts with a friction-optimized super-fine surface, finger followers with a DLC coating are taken over as well as four lightweight titanium valves (intake 36.3mm, exhaust 29.1mm). The flow rate has been maximized for an optimal power which ends at an engine speed of 13,400 rpm.

The 88mm, forged, bridge box, CP piston has its crown geometry designed to work perfectly with thee high-compression combustion chamber. The compression ratio is at 14:1.

A newly designed diaphragm steel (DS) clutch features a one-piece steel clutch basket with the primary gear machined into it. The diaphragm spring (belleville washer) reduces the operating force required to pull the clutch.

Formula 1 supplier Pankl now makes the five-speed transmissions on the 2019 KTMs. All four-stroke engines are fitted with a gear sensor giving the option of different engine characteristics for each gear.

The Keihin Engine Management System, with electronic fuel injection, features a new 44mm throttle body, reworked throttle cable mount, and improved seal of the Manifold-Absolute-Pressure (MAP) sensor makes the system even more reliable. The ECU features new maps adapted to the new exhaust and cylinder head and it regulates the unique traction and launch control. In addition, it provides different maps for optimal power characteristics for each gear.2019 250SXF ENGINE
The 250 SXF engine is known to be the strongest engine in its engine class. And with updates on valve timing, exhaust, airbox and EMS the entire power pack produces even more torque and power across the entire rpm range up to 14,000 rpm. The centerpiece of the compact DOHC (double overhead camshaft) engine is the cutting-edge cylinder head. It features two overhead camshafts which activate the titanium valves (intake 32.5mm, exhaust 26.5mm) via superlight finger followers. The exhaust camshaft features a new timing for improved power delivery. With a low engine weight of only 57 pounds (including electric starter) the KTM 250SXF is the lightest bike in the 250 class.

A newly developed DS (diaphragm steel) clutch features a one-piece clutch basket combined with the primary gear made of high-strength billet steel. It guarantees unbeatable reliability and contributes to the narrow engine size due to its compact rivet-less design. The DS clutch is pre-tensioned by diaphragm spring, which substantially reduces the operating force required to pull the Brembo hydraulic clutch.

The 2019 KTM 250 SXF uses a new five-speed transmission made by Pankl. All 2019 KTM four-stroke engines are fitted with a gear sensor giving the option of different engine characteristics for each gear.

The Keihin Engine Management System, with electronic fuel injection, features a new 44mm throttle body, reworked throttle cable mount, and improved seal of the Manifold-Absolute-Pressure (MAP) sensor makes the system even more reliable. The ECU features new maps adapted to the new exhaust and cylinder head and it regulates the unique traction and launch control. In addition it provides different maps for optimal power characteristics for each gear.2019 KTM 250SXF four-stroke.

2019 KTM 250SXF, 350SXF & 450SXF WHEELS/BATTERY/WIRING HARNESS
The KTM wheels feature CNC machined hubs and high-end Excel rims, but for 2019 the aluminum nipples will feature a reworked design to reduce the frequency of spoke tightening the spokes. The tires are a Dunlop Geomax MX3S combo.

250SXF, 350SXF and 450SXF four-strokes new and more capable, super lightweight, 2 Ah, Lithium-Ion (lithium-iron-phosphate) starter battery provides even quicker starting (especially at cold weather conditions) and contributes to the low vehicle weight. A reworked packaging of the voltage regulator and condenser concentrate the electrical components in a tray below the seat and makes the entire system even more reliable.

KTM’s 48mm WP air forks make the suspension on the 250SXF, 350SXF and 450SXF completely adjustable for any size rider.

2019 WP AER AIR FORKS & TRIPLE CLAMP
All 2019 KTM models are fitted with the lightweight WP AER 48mm front fork. The damping functions are in the right fork and the air spring is in the left. The left leg features a two-chamber air system with a capsuled air cartridge to prevent loss of air pressure—even if an the outer fork seal leaks the internal cartridge pressure stays the same. There is only a single air valve to adjust and an air pump is supplied with the bike.

The CNC-machined triple clamps feature a stiffer upper triple clamps (5% stiffer). The rubber-damped bar mounts reduce the vibration level and are two-way adjustable. An hour meter comes stock already mounted on the top triple clamp.

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