Guru On November - 28 - 2011

Royal Enfield Maintenance Tips-chapter-5

In this session, how timing of any Royal Enfield Bullet classic work and also will throw some light on idling speed and gear ratio of a motorcycle engine.

Ignition timing of any motorcycle is the timing in degrees of rotation of crank shaft at which spark commences so that the spark from the spark plug can ignite the mixture in the combustion chamber at the end of top dead center during compression stroke.  If spark occurs earlier than specified ignition timing, it is called “Advance” timing.  If spark occurs after the specified ignition timing, it is called “Retard” timing.

Idling speed of a motorbike engine is the speed of crankshaft in revolution per minute when the throttle is in closed position.

 Bullet Classic-Gear Ratio

The relative rotation between “Driven Gear” and “Driving Gear” is known as the “Gear Ratio.”  It is determined by number of teeth on the respective gears.

Gear Ratio = No. of teeth of Driven Gear

No. of teeth of Driving Gear

Gear ratios multiply the engine torque to fulfill various demands for pulling the motorcycle like.

More effort is required during initial movement of the motorcycle

More effort is required to climb an elevation by the motorbike

More effort is required while driving in muddy or sandy surfaces etc by the motorcycle

Bullet Classic -Final Drive Ratio

It is a relative rotation between the engine sprocket and the sprocket on the rear wheel.  Both the

Sprockets are connected through drive chain.  Final drive ratio further multiplies the torque available at the output shaft of the gear box of the motorcycle.

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