Compression Gauge
A compression gauge kit usually includes a hose and fitting which screws into the spark plug hole in an engines cylinder head along with the gauge itself. When a compression test is performed while cranking the engine, the gauge provides a reading of the cranking pressure in the combustion chamber and provides some idea as to the condition of the engines top end.
Cold Cranking Amps
The measurement of cranking amperes a battery can deliver over a period of 30 seconds at 0°F (-18°C). Commonly used to rate automotive batteries, it is not usually used to rate motorcycle batteries. Motorcycle batteries are rated in Amp/hours (A/h), that is, how many hours can a fully charged battery supply one amp of current to a load. The larger a motorcycle battery is physically, the greater its Amp/hour capacity.
Capacitor
Also known as a condenser. An electrical component that is made up of two metal sheets separated by an insulator. It is designed to store an electrical charge.
A popular “hop-up” in the racing and off-road community is to replace the battery in a motorcycle with a large capacitor. The capacitor stores enough electrical energy from the alternator to operate the ignition system and related electrical components. These kits are available as “battery eliminators” and help to save weight and cut down on maintenance. The drawback of replacing a battery with a capacitor is that you will lose the ability to operate an electric starter.
Caliper
Hydraulic disc brake systems utilize brake calipers to hold and actuate the brake pads. The brake pads are held in place so that the brake disc is positioned between them. The caliper has one or more pistons which use hydraulic pressure to push the brake pads against the brake disc which in effect squeezes the rotating disc connected to the wheel and creates the braking action. Calipers are filled with brake fluid and are connected to a master cylinder by the way of a brake line. The master cylinder supplies the hydraulic pressure. It is important to routinely inspect and even rebuild the brake calipers on a motorcycle or ATV. The word “caliper” can also be used for a type of measuring tool that clamps around the component being measured, much as the brake caliper clamps around the brake disc. These measuring calipers can be Vernier, dial or digital types.
Squid
We’ve all seen him before - he’s the idiot riding that bike down the highway with flip-flops on his feet, his T-shirt riding up his back, flipping around with the wind. He MAY have a pair of gloves on but don’t count on it. He’s most likely got a decent helmet but you’ll often find it partially on his head or hanging from the helmet lock when he’s riding around town cruising. He may be riding a sportbike, Harley, a dirt bike or even an ATV - regardless he is a bad rider and needs to grow up.
If he’s riding a sportbike he is likely to be passing cars by dangerously zig-zagging through them on the highway. People in cars are shaking their heads and raising their fists. He cares more about who is watching him ride than actually enjoying the ride. He looks for his reflection in store windows so he can watch himself riding by.
He squares off his turns and slows down in a jittery fashion but he is sure to punch it when the road opens up. His bike may be all tricked out, maybe it has some neon lights on it even - it is most likely loud. If he scrapes up the cash to buy a good set of leathers he still rides like an idiot and gives other bikers a bad name. He needs a good kick in the ass and should be sent to Rider Safety Training. For now he is just another squid.
Die Tool
A tool specially made for cutting and cleaning male threads on bolts and studs. Dies are included in tap and die sets available from most tool suppliers.
Flywheel Magneto Ignition System
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.
Magneto
The term magneto is, of course, derived from the word magnet. It refers to a magnetic flywheel (usually bolted on the end of the crankshaft) spinning near a coil of wire, which will produce AC voltage. This AC voltage can either be used directly to power an ignition system or lighting system, or it can be rectified into DC voltage to charge the battery or power any DC circuits on the motorcycle.
Flywheel
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.
Reed Valve
Motorcycle two-stroke engines feature a one-way valve positioned in the intake port. The valve is made up of a reed cage that holds the reed petals. The petals prevent the backward flow of crankcase air/fuel mixture out of the carburetor. Reed valves should be inspected on a routine basis. Over time, reed petals can fatigue and break loose causing severe engine damage.
