INSIDE KTM’S 2007 450SXF: ALL ELECTRIC START

On May 9, 2006 Last updated Feb 22, 2018

(All photos by Ray Archer)

   KTM has unveiled it’s next generation of motocross machines at the second round of the FIM World Motocross Championship at Bellpuig, Spain last weekend. Factory rider Jonathan Barragan rode the 450 SXF to fourth place on it’s debut. It’s understood that Sebastian Tortelli was given the opportunity to ride the bike but decided to stick to his regular mount.

    “I am really happy with the new bike,” Barragan said. “The engine is strong with a softer power delivery. The plastics are new and the tank feels a little wider but my impressions are good and I am keen to keep developing the bike.”

       The new 450 SXF is driven by a completely re-developed four-stroke single cylinder engine with 449cc displacement and twin overhead camshafts. Four super-lightweight titanium valves and a DLC- oated rocker arm work together with the compact cylinder head of the engine with high revving abilities. For the first time the motocross bike will come with an electric starter to set the 59 hp power unit with its Keihin carburetor in motion. The application of this new technology means a significant time saving at the start.

   The frame is made from generously dimensioned, oval tubular profile allowing for more space for the cooling system. Improved rigidity means that the weight of the new frame can be further reduced.

    The new, weight-optimized, light cast metal rocker, new geometric data from the latest PDS absorber system as well as a totally new WP Suspension upside down fork with integrated cartridge absorber system collectively transforms the SX chassis into the most advanced, high-quality unit in the entire offroad sector.

    When it comes to look and feel on the new SX generation, the KTM development engineers have paid special attention to perfect ergonomics and maximum ease of use. It is often the case that the first serious feedback that serves as the key to success comes as a result of tough off-road application. This is why the 450 SX-F is the first model of the new generation that features a fresh design for the tank section that now has a distinctively larger contact surface. In order to achieve the best possible feeling with the rider in every situation, the seat has also been totally overhauled. The new SX, with its numerous modifications, also has a new and very aggressive appearance that represents an unmistakable aesthetic milestone for KTM.

Motocross fans throughout the world however will still need a little patience before the final release of this model. Along with the new lines of KTM 125 SX, 250 SX and the 250 SX-F machines, the 450 SX-F will be officially presented to the international media in Mattighofen at the end of June. Delivery of the entire latest generation of KTM SX will follow immediately after.

2007 KTM PTOTOTYPE TECH SPECS

ENGINE
Engine Type: Single cylinder, 4-stroke
Displacement (cc): 449.3
Bore x Stroke (mm): 97 / 60.8
Compression ratio: 12,5 : 1
Performance: approx. 59 HP
Starter: electric starter
Transmission: 4 gears
Carburetor: Keihin MX FCR 41
Control: 4V / DOHC with finger levers
Primary ratio: 29 : 74
Final drive: 5/8 x 1/4″
Cooling: Liquid cooled
Clutch: Wet multi-disc clutch, operated hydraulically
Ignition: Kokusan digital CDI

CHASSIS
Frame: Chromium molybdenum
Subframe: Titanium
Handlebar: Aluminium
Front suspension: WP-USD 52 MA
Rear suspension: WP-PDS shock absorber
Suspension travel front/rear: 300 / 335 mm
Front brakes: Disc brake 260 mm
Rear brakes: Disc brake 220 mm
Front/rear rims: 1.6 x 21″ / 2.15 x 19″
Front/rear tyres: 80/100-21″ / 110/90-19″
Transmission ratio: 14:50
Main silencer: Titanium
Steering head angle: 63.5ø
Wheel caster: 112 mm
Wheelbase: 1481ñ10 mm
Ground clearance (unloaded): 380mm
Seat height (unloaded): 925mm
Fuel capacity: approx. 7 liters
Weight: approx. 100 kg