KTM revs up four-strokes for 2015

Publish Date: 
Jun 3, 2014

MURRIETA, Calif. - KTM announces major revisions to its 2015 model year four-stroke lineup. The company also revealed performance, stability and handling upgrades for its two-strokes and minis.

250 SX-F
"The 250 SX-F is once again a World Championship winner in MX2 and adds a prestigious AMA Supercross Lites Championship in 2013 and 2014 to its amazing trophy cabinet," KTM said. "The 2013 season was a great success in racing at all levels around the globe. The performance combination of a powerful and lively engine in a lightweight and agile chassis is sure to make the 250 SX-F the star of the show for yet another year."

Engine revisions include a lighter clutch basket and new clutch springs for a more consistent behavior under stress and over time as part of the CSS (coil spring steel) one-piece clutch system. The clutch continues to use a Brembo hydraulic system for light operation and controllable modulation. Within the proven DOHC engine are also new O-rings on the oil pump suction screen for increased durability.

For 2015, the 250 SX-F continues to use the Keihin engine management system with EFI and a 44mm throttle body, a quality wire harness, lightweight gearbox, and electric starter.

Features include:

  • Compact DOHC engine with two overhead camshafts and DLC-coated followers
  • Titanium valves (intake 32.5mm, exhaust 26.5mm)
  • RPM limit of 14,000 rpm
  • Flow optimized ports
  • Forged box-type piston for a low oscillating mass
  • A crankshaft employing a plain big end bearing for longer service intervals
  • New O-rings on the oil pump suction screen for increased durability
  • A multifunctional counter balance shaft, which drives the water pump and timing chain for reduced vibrations
  • An electric starter as standard
  • Lightweight and compact CSS clutch with eight clutch plates and a hard-wearing steel basket
  • New clutch basket with a weight-saving design
  • New clutch springs for more consistent behavior
  • Lightweight five-speed gearbox for precise and easy shifting, adapted for the 250 SX-F
  • An engine management system for a spontaneous throttle response, and an ability to change characteristics or read engine data with an optional User-Setting-Tool

350 SX-F
With the bike's low weight, playful agility and a high-revving engine, "it enjoys all of the very best characteristics in a package suited to amateurs and pros alike," KTM said.

For 2015, the 350 features a DOHC engine with lightweight titanium valves and DLC-coated followers for spontaneous power delivery, along with a crankshaft that has been designed to increase service intervals. New O-rings increase durability on the oil pump suction screen. An electric starter is standard. A new lighter clutch basket with new clutch springs compliments the CSS clutch with the Brembo hydraulic system for easy and precise control of a 250-agile bike with the power that can match a 450, KTM said.

More specifically, the 350 SX-F features:

  • A DOHC Cylinder head with ultra lightweight titanium valves and DLC-coated followers for a spontaneous power delivery and 450-rivaling maximum power
  • A crankshaft that employs a plain big end bearing and force-fitted bearing shells for longer service intervals
  • New O-rings on the oil pump suction screen for increased durability
  • A multifunctional counter balance shaft, which drives the water pump and timing chain for reduced vibrations
  • Electric starter as standard
  • CSS clutch eight clutch plates and a hard-wearing steel basket
  • A new clutch basket with a weight-saving design
  • Lightweight five-speed gearbox for precise, easy shifting adapted for the 350 SX-F
  • An engine management system for a spontaneous throttle response, and the option to change characteristics or read engine data with a separately purchased User-Setting-Tool

450 SX-F
The 450 SX-F is the weapon of choice for the Red Bull KTM Factory Race team in the AMA championships thanks to its compact SOHC engine that delivers explosive but controllable power, combined with an agile and stable chassis, KTM noted.

The 450 features:

  • A compact 60hp power pack with a single overhead camshaft and the latest electronic fuel injection
  • A single overhead camshaft controlling four ultra-lightweight titanium valves via "extremely rigid" rocker arms, DLC-coated on the intake side
  • Engine speeds of up to 11500 rpm and a three-layer head gasket for durability under the most extreme conditions
  • Bore of 95mm with a lightweight box-in-box type piston for low engine vibrations
  • A crankshaft that employs a plain big-end bearing and force-fitted bearing shells for longer service intervals
  • A side-mounted counter balance shaft that also drives the water pump
  • Electric starter as standard
  • A DDS clutch with Brembo hydraulic actuation -- a compact design that integrates an internal damping system
  • Lightweight five-speed gearbox for effortless shifting
  • New O-rings on the oil pump suction screen for increased durability
  • An engine management system for a spontaneous throttle response and an option to change characteristics or read engine data with a separately purchased User-Setting-Tool.

Read about the two-stroke and mini updates for 2015 HERE

From a press release. Media images courtesy KTM