Engine management system (EMS)
Apart from controlling EFI parameters on the 4-strokes, the Keihin EMS features selectable engine maps via the switch on the handlebar as well as traction control. Combined with the gear sensor, power delivery is tailored for each gear.
- Keihin EMS → smaller, lighter and faster at processing engine data for more efficient engine management
- Gear sensor → specific engine maps for each gear
The EMS features an electronic control unit (ECU) on the 2-strokes, which is responsible for a number of functions. The unit determines ignition timing and amount of fuel and oil injected. It also receives information from the throttle position sensor, ambient air and intake pressure sensors as well as crankcase pressure and water temperature sensors to adapt values and make corrections for automatic temperature and altitude compensation. Prior to fuel injection, this would have meant changing carburettor jets.
The 4-stroke range features a 42mm Keihin throttle body. The injector is positioned for the most efficient flow into the combustion chamber, while to ensure optimal throttle response the throttle cable is mounted directly without a throttle linkage.
- Throttle body → 42 mm, injector positioned for optimal flow, more immediate throttle response thanks to direct cable mounting
The 2-strokes use a 39 mm throttle body which regulates the amount of air entering the engine via a butterfly operated by dual throttle cables connected to the handlebar throttle assembly. Unlike 4-stroke throttle bodies, fuel is not introduced at this point, but rather 2-stroke oil is mixed with the air entering the engine to lubricate the crankshaft, cylinder and piston. Additionally, a throttle position sensor (TPS) relays airflow data to the ECU which in turn calculates the amount of oil and fuel delivered to the engine while a bypass screw regulates the idling speed and a cold start device opens an air bypass for cold starts.
- 39 mm throttle body → regulates air flow, TPS relays airflow data
Tailored specifically for each model using an innovative 3D design process, the 2-stroke header pipes feature advanced geometry and performance. The TE 250i/300i header pipe offers more ground clearance making it less susceptible to damage, while a corrugated surface makes the header pipe more durable to rock damage and other hazards found on the enduro trail. The 2-stroke mufflers also feature an aluminium mounting bracket and advanced internal construction for excellent noise damping and weight saving.
The 4-stroke exhaust system is designed to deliver class-leading performance for the lowest possible weight. The header pipe is designed and manufactured in two pieces, to be as compact as possible. The joining arrangement allows it to be removed without having to take out the rear shock. Further innovation allows for a short, compact silencer without increased noise levels. The component is crafted from lightweight aluminium and is stylishly finished in a black coating to highlight its premium quality.
- Corrugated surface on TE 250i/300i → less susceptible to damage
- Header joining position on 4-stroke → remove without removing rear shock