Frontal bodywork on a motorcycle intended to make the vehicle more aerodynamic and/or reduce wind pressure on the rider. Common types of fairings include flyscreens (very small shields placed over the headlight), bikini fairings (small fairings that fit completely around the headlight), half fairings and full fairings. In the 1950s roadrace motorcycles used what were called dustbin fairings that covered virtually the entire motorcycle, but these were outlawed due to the danger of cross winds blowing the motorcycle off of the racetrack!
Most motorcycles have a fuse block which houses a variety of fuses for different electrical circuits on the vehicle. Fuses protect electrical circuits from overloading by sacrificing themselves before damage can occur to electrical components or wires connected to the circuit. Most fuses contain a small filament, much like an incandescent light-bulb. When a circuit is overloaded the filament or link in the fuse melts and opens the circuit to prevent further damage. Fuses are rated by amperage limits they are designed to withstand. If the wrong size fuse is used it can cause damage to a circuit or cause premature failure of the fuse. Never replace a fuse with metal foil or wire once it has blown. AC circuits (ignition or lighting) will not be fused.
A flywheel puller is a special tool designed to quickly and safely remove a flywheel from the crankshaft of an engine without damage. Using the correct flywheel puller and using it properly will help you avoid damaging the threads on the crankshaft end. It is important to note that flywheels contain magnets which can be damaged or ruined if the flywheel is struck by a hammer or lands on the ground.
Flywheels usually fit onto a tapered shaft and become wedged onto the shaft when the flywheel bolt is torqued down, making the flywheel difficult and unsafe to remove without a flywheel puller. Gloves and goggles should always be used when removing a flywheel – sometimes flywheels break free with violent force and have been known to fly across a room on unsuspecting mechanics.
A good quality flywheel puller is a precision tool and it is very important to properly lubricate it prior to use. You can achieve good results with an anti-seizing lubricating agent or high-quality grease.
The system whereby the transmission output shaft drives the rear wheel of a motorcycle or ATV. Chains and sprockets are most often used on sport and off-road motorcycles. Shafts and gears are most often used on touring motorcycles and four-wheel drive ATVs. Belts and pulleys are used on many cruiser type motorcycles. A few experimental motorcycles have used hydraulic fluid to drive the rear wheel.
An AC ignition system using a generating coil (commonly called a source coil or exciter coil) and either a pickup coil (used in a Capacitor Discharge Ignition) or contact points (used in an Energy Transfer Ignition) as well as a magnetic flywheel to provide primary ignition current and switching. An external ignition coil is used to step up the voltage in order to produce a spark at the sparkplug.
A flywheel is an assembly consisting of weights that is bolted to an engine crankshaft to provide additional inertia during non-power producing strokes. The flywheel helps to smooth out abrupt movement of the crankshaft during the power stroke. Aftermarket flywheel weights can be purchased for some motorcycles to change the power characteristics of the engine. An engine fitted with a lighter flywheel will be more responsive to throttle input and rev faster – it will also be prone to easier stalling. An engine fitted with a heavier flywheel will be less responsive but will retain its power through inertia of the flywheel and be less prone to stalling. A heavy flywheel is desirable on a trail-bike being used in tight technical situations while a light flywheel is desirable on a motocross bike being run on a wide open track.
A precision made steel strip that is manufactured to a variety of exacting thicknesses for the purpose of measuring gaps between components. Feeler gauges are commonly used to check motorcycle spark plug gaps, valve clearances and for inspecting cylinder heads or clutch plates for any warping.