Motorcycles Technology

Save Fuel just by driving normally, with Honda's Idling Stop System

1. What is the Idling Stop System?

Normally, once you start an engine, it continues to consume fuel until you switch it off. In other words, it burns gas unnecessarily at traffic lights and other brief stops.

The Idling Stop System automatically switches the engine off at traffic lights and other brief stops, eliminating wasteful fuel consumption.

When the Idling Stop System is switched on, it automatically turns the engine off and on for you when you stop and start up. This results in a fuel saving of approximately 7%, compared to when the system is not in operation (according to Honda testing using ECE R40 mode).

What is ECE R40 mode?

ECE R40 mode

ECE R40 mode is a driving pattern widely adopted for exhaust emission testing around the world. During testing, the vehicle is accelerated to predetermined speeds, decelerated, and stopped within a specified time frame; this pattern is repeated several times, then researchers calculate the amount of fuel consumed.

2. All the rider needs to do is drive normally

Idling Stop System Switch

All you need to do is switch to Idling Stop mode.
The engine automatically turns off at traffic signals and other brief stops1. When you’re ready to go, just turn the throttle grip and it starts up again instantly.

1 Engine coolant temperature must be over 60˚C for system to operate.

3. The AC generator-equipped Idling Stop System features quiet starts

Honda developed an ACG (AC generator) starter-type Idling Stop System for the PCX—a first for a 125cc-class motorcycle and scooter*—in order to deliver comfortable operation even as Idling Stop is put to work frequently in city driving.
*According to Honda survey

In the Idling Stop System, the engine is started via the same AC generator used to generate electricity and charge the battery while riding. This eliminates the need for a conventional starter motor, thus there are no reduction gears and gear meshing noises – just smooth, quiet starts.

4. Starting the engine with a small amount of force

In order to be able to start a 125cc-class engine like the one in the PCX with a compact ACG starter, Honda incorporated a number of innovative ideas in engine design.


To start the engine,the fuel-air mixture inside the cylinder needs to be compressed, requiruring considerable power. 
To compensate, the exhaust valve is opened slightly, reducing the amount of power required for compression.

The decompression mechanism operates only at startup, not during normal engine operation.


The engine is rotated slightly in the opposite direction before starting. This allows the piston to take a ‘running start’, making it easier to start the engine with a small amount of power.

5. Efforts to improve motorcycle environmental performance

Motorcycles are already comparatively easy on the environment and economical, but Honda is engaged in a variety of initiatives in order to further improve their environmental performance.

Using alcohol-based fuel made from plants

Using alcohol-based fuel made from plants

Alcohol-based fuel made from plants does not increase the net amount of atmospheric CO2 when burned. Honda has developed a Mix Fuel Injection System capable of running on both gasoline and alcohol for use in Brazil, where use of alcohol-based fuel is widespread.

Making scooters that run on electricity instead of gasoline

Making scooters that run on electricity instead of gasoline

The electric scooter EV-neo emits no CO2 in operation and offers quiet operation. The introduction of leasing of this product with its superior environmental performance is a key first step toward the popularization of electric scooters.

In addition to these initiatives, Honda is also working to improve existing gasoline engines, so that they will be able to perform more work using less fuel.

Improving gasoline engine efficiency

4-stroke engines

4-stroke engines

Honda employs fuel-efficient, cleaner-burning 4-stroke engines in all its motorcycles, including its 50cc-class models.



Honda employs fuel-efficient PGM-FI (electronic fuel injection) in most models, from small scooters to large-displacement motorcycles.

Friction reduction

Friction reduction

Honda continues to develop technologies to minimize the friction produced during engine operation.

Idling Stop System

Idling Stop System

The Idling Stop System enables the engine to produce zero exhaust emissions when it is engaged and the vehicle is stationary.