VALVE TRAIN

The crankshaft drives a laterally positioned intermediate shaft that also acts as a balancer shaft, water pump drive and timing chain drive for the two camshafts. A hydraulic chain adjuster ensures reliable chain tension and consequently extremely precise valve timing.

ENGINE

The 350cc four-stroke engine, with state-of-the-art electronic fuel injection, provides a very broad useable rev range and distinguishes itself with dynamic yet strength-saving engine characteristics. With peak power of more than 45 hp, the 350 EXC‑F is powerful enough to beat every 450 in the E2 class.

OIL CIRCUIT

The 350 EXC‑F engine is equipped with two oil pumps. A pressure pump supplies reliable lubrication to the crankshaft, piston, balancer shaft and valve controls. It also ensures cooling of the ignition and lubrication of the clutch. A suction pump draws oil from the crankcase and uses it to lubricate the transmission. This creates a slight vacuum in the crankcase, which also increases engine performance.

DDS CLUTCH

The single-piece outer hub of the further optimised DDS (Damped Diaphragm Steel) clutch is machined along with its primary gear from a solid block of high-strength steel. This process guarantees unbeatable reliability and allows the engine to be extremely narrow thanks to the compact, rivetless design of the outer clutch hub. In addition, this design allows use of thin steel discs, which also contributes to the compact dimensions of the clutch. The diaphragm spring enables implementation of an additional hub damping mechanism - a benefit in terms of traction and gearbox wear. Furthermore, an optimised inner clutch hub improves the durability of the clutch. Finally, in conjunction with the diaphragm spring, the hydraulic clutch actuation system from Brembo ensures very smooth and very precise clutch control.

TRANSMISSION

The six-speed transmission is designed specifically for the engine characteristics of the 350cc and 450cc engine and for every type of enduro use. It excels with precise and easy shifting.

BALANCER SHAFT

To counterbalance the inertia forces, the 350 EXC‑F engine is equipped with a balancer shaft on the right-hand side, which acts simultaneously as a water-pump drive and a drive wheel for the timing chain. This solution makes a major contribution to the extremely compact design of the engine.

ENGINE MANAGEMENT SYSTEM (EMS)

The engine management system from Keihin, with electronic fuel injection and 42 mm throttle body, ensures spontaneous responsiveness and maximum engine performance. Various engine characteristics can be selected via the EMS, with a map-select switch available as a PowerPart. Furthermore, a user-setting tool (also available as an option) allows data to be read from the bike by laptop and the mapping, ignition and fuel injection to be modified in a matter of a few mouse clicks.

ENGINE CASE

The engine case production process was already converted from sand casting to die casting in the previous model year in order to reduce the wall thickness and save weight. In MY 2014, the optimised gasket for the new water-pump cover guarantees absolute reliability even in the toughest of conditions.

CRANKSHAFT

Compared with the 350 SX‑F, the 350 EXC‑F is equipped with a heavier crankshaft to generate more gyrating mass for more uniform power development and better traction. Similarly to last season's KTM SX-F models, it is equipped with a plain bearing in the lower conrod eye. The previous needle bearing is replaced with two press-fit bearing shells that run directly on the crankshaft's crank pin. This design enhances the durability of the engine, thereby enabling an extension to the service intervals for the crankshaft.

CYLINDER HEAD

Together with very small, lightweight (only 8 g) cam followers with DLC coating, the DOHC cylinder head is equipped with four ultra-light titanium valves (intake 36.3 mm, exhaust 29.1 mm), allowing extremely high engine speeds of up to 12,000 rpm. The valve timings of the camshafts are designed perfectly for performance in the enduro-specific lower rev range. New valve spring retainers ensure even greater durability in the most extreme conditions in MY 2014 and a revamped auto-decompressor optimises starting behaviour.

STARTER

The engine is equipped as standard with both kickstarter and electric starter. Positioned behind the cylinder, the electric starter is well protected. Its drive is connected to the optimised freewheel on the ignition rotor.

ALTERNATOR

The 350 EXC‑F engine is equipped with a 196 watt alternator featuring an integrated freewheel for the starter. The alternator provides sufficient power for the fuel injection system, lights and other electrical loads. Compared with the 350 SX‑F, the oil-cooled rotor has a larger diameter, which provides more gyrating mass and requires a larger ignition cover.