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.

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.

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.

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.

Christini Technologies Inc. designs and builds an All Wheel Drive motorcycle. In their fully mechanical system (no hydraulics or electronics,) power is in fact sent to both wheels at different ratios making it all wheel drive. The front wheel free-wheels until the rear wheel slips. Drive ratios to the front are between 60% and 80%. Once the rear wheel turns faster than the front wheel, the front wheel drive engages.

For more information see: http://www.christini.com/

The part of an engine where combustion of the air-fuel mixture takes place in the cylinder head. In two and four-stroke engines, and diesel motors, the combustion chamber refers to the space between the cylinder head and piston crown.

A one-piece engine cylinder made of cast iron with a precision machined cylinder bore. The porosity of cast iron retains oil for piston and ring lubrication, but it is very heavy. Many motorcycles have aluminum cylinders with cast iron sleeves to help reduce weight.