A good toothed belt; timing belt; cogged belt; cog belt; or synchronous belt is a versatile belt with teeth moulded onto its internal surface. It is designed to run over coordinating toothed pulleys or sprockets . Toothed belts are found in several in mechanical gadgets, where high-power transmission is desired.
Toothed belts are used widely in mechanical devices, including 
sewing machines ,photocopiers and many others. A major usage of toothed belts is really as the timing belt utilized to operate a vehicle the camshafts within an vehicle or motorcycle engine.
As toothed belts can deliver more power than a friction-drive belt, they are used for high-power transmissions. Included in these are the primary drive of some motorcycles , notably afterwards Harley-Davidsons ;and the supercharger used for dragsters .
Microlight aircraft driven by high-speed two-stroke engines such as the Rotax 532 use toothed belt reduction drives to allow the use of a quieter and more efficient slower-rate propeller. Some amateur-built airplanes run by automotive engines make use of cog belt reduction drive units.
A tooth pulley has some teeth whereas a set belt pulley doesn’t have any teeth.
The tooth pulley is utilized when accurate transmission of the torque is necessary. Toned belt pulleys or V-belt pulleys cannot deliver 100% accurate tranny of the torque because there’s always some (very little – but nonetheless) slipping between the pulley and belt.
TOOTHED PULLEY / TIMING BELT
Ever-power pulleys that specialize in engagement transmission
Pointer through this to learn more regarding Toothed pulley.