A type of engine used in some karting classes. The most common engines are manufactured by Briggs, Honda or Tecumseh. An excellent discussion on how a 4-cycle engine works can be found here.

The Ackerman effect is the increase of toe-out on the front wheels as the wheels are turned in a curve. The toe-out increase is reverse-proportional to the turn radius, i.e. the steeper the curve, the more toe-out. Just optically the effect seems to be that the inside front wheels appears to turn 'more' than the outside front wheel, which is in line with the observation that the inside front wheel actually needs to traverse a tighter curve than the outside wheel. It depends on the track if you really need Ackerman steering or not. In order to implement Ackerman steering, a special steering column is needed in which the two tie rods are not mounted into the same bearing hole, but rather in two separate holes which are located next to each other, and by a certain angle offset to the left and right of the kart's center-line. Thus, the two steering-column-side ends of the tie rods will have rotated to a different angle (as measured relative to the center line) when the steering wheel has been turned. This in turn will cause the tie rods to pull the pitman arm of the inside spindle more inward than the pitman arm of the outside spindle is pushed outward.

Adhesion

See stickyness.

Air box

A plastic contraption, which looks like a bottle with a rounded bottom, which is placed over the air filter. The air box has either two or three holes, which allow air to enter the box. It is mandated by many clubs and series' since it supposedly reduces the noise level of the engine.

Air cooled

Most karting engines are air cooled, i.e. the engine is radiating off exess heat in the surrounding air. These engines typically have fins to accomplish this. Air cooled engines are simpler than water cooled engines, but are typically louder as well and are overheating more easily.

Air filter

A device to filter the air before it enters the carburetor. There are foam filters, wire-mesh filters, and some people just have a sock over the carburetor. There are advantages and disadvantages to all of thse means. The wire-mesh filters appear to be most common these days.

Air filter spray

A special spray used to clean wire-type air filters. Special light oils may also be used to clean foam-type air filters.

Air tank

A portable, pressurized tank which will make inflating tires a breeze. Highly recommended.

Alignment

The positioning of the front wheels of a kart relative to each other. There may either be toe-in or toe-out. The rear wheels are always perfectly aligned, since they are mounted on a stiff axle (as long as the axle is not bent).

Apex

The inside portion of a curve where the vehicle should be closest to the kerb in order to take the fastest way around the track. This is often, but not always, the geometric center of the turn. Hitting the apex just right will be an important art to learn for every new driver. Driving a late apex, i.e. hitting the inside curb after the geometric center of the turn, will often result in higher lap-times, while hitting the apex early will often result in desaster. Certain track characteristics might warrant a late apex or early apex, though. Strictly speaking, the apex is actually always the geometric center of the bend. But drivers tend to use this term to describe the clipping point, i.e. the point where the car is closest to the kerb and travels the slowest.

Asphalt oval

As the name implies, racing on an oval track, made from asphalt. See speedway.

Asphalt racing

Racing on a hard, smooth surface (asphalt, concrete) as compared to dirt racing. Slick tires are used. The kart setup may differ significantly from dirt racing.

Axle

A round, typically hollow metal bar on which the rear wheels are mounted on. The brake disc(s) and sprocket (gear) are also mounted on it. The axle sits on two or three rear axle bearings, depending on make and setup of the kart. The bearings are mounted in the axle cassettes. Axles of different thickness are used, the thicker (stiffer) ones in the faster classes where the tires typically develop more grip and the flexing of the frame should be less.

See weight.

Battery

A kart does not have a starter engine built in. Instead, a separate starter is used. The battery is mounted into the starter.

Bead breaker

A tool for dismounting tires from wheel rims.

Bearing

Where rotating parts are mounted in. The front wheels are mounted on bearings to the spindles, while the rear axle is mounted on either 2 or 3 bearings, which are housed in the axle cassettes, to the frame. They need to be replaced occasionally, typically once a season.

Binding

A term used to describe the kart slowing down excessively in the turns because both rear tires are planted too firmly. See also understeer, as that is the extreme case of binding. See handling.

Black flagging

A black flag is show to a driver by race officials when he/she is disqualified, i.e. needs to end the race instantly. This typically happens as a result of a rules violation. See also flag man.

Blades

Another term for torsion bars.

Blue printing

What the engine builder does to a new, stock engine to make it competitive. It is a costly procedure (several hundred to more than a thousand dollars) in which the new engine is taken completely apart, and all parts are machined to the (hopefully allowable) limit, in order to get as much performance out of the engine as possible. Non-blue printed engines are often not competitive.

Body work

Various plastic pieces and panels attached to the kart. The amount and measurements of the body work may be regulated. Typical pieces of body work are: The front nose, side pods or side panels.

Books

A great source of knowledge for any new karter. There are some excellent racing books and even specific karting books. Good books are certainly worth the investment and will save you alot of time and money and disappointemnts. For a selection of good racing books click here.

Brake

The system to slow down a moving vehicle. In a kart with only rear brakes this consists of brake pedal, brake tie rod, master cylinder, brake hoses, brake fluid, slave cylinder, brake pads and brake disc.

Brake disc

The brake disc is mounted on the rear axle and rotates with the same speed as the axle itself. The disc is aligned to sit precisely between the two brake pads which in turn are mounted into the slave cylinder. When the brake is applied, a lot of heat can be generated from friction on the brake disc. Hence, various designes and materials are used for the brakes. The disc is typically grooved in a manner which is designed to facilitate heat dissipation. The disc is vented. There are also double disc assemblies, which are more resistant against warping. There are also 'floating' brake discs, which have the benefit of aligning themselves. The brake disc is also called the brake rotor.

Brake actuating rod

A different name for brake tie rod.

Brake fluid

Brake fluid fills the master cylinder, the brake hoses and the slave cylinder. It is specially design to withstand the heat in the brake system and to transmit the mechanical pressure from the brake pedal hydraulically to the slave cylinder. Various brands are offered. When the brake fluid is replenished, care needs to be taken not to introduce any air bubbles into the brake system. Air will compress under pressure and make the braking performance less predictable and give it a 'squishy' feel.

Brake hoses

There are typically two brake hoses connecting the master cylinder with the slave cylinder. (Several slave cylinders on karts with front brakes). The hoses are made of a clear plastic, to make it easier to check for undesired air bubbles in the brake fluid which flows through the hoses.

Brake pads

There are typically two brake pads mounted to the calipers inside of the slave cylinder. When the brake is applied, the brake pads are pressed down by the calipers on the rotating surface of the brake disc. Through friction, the kart is therefore slowed down. Brake pads need to be replaced quite regularly.

Brake pedal

The brake pedal is typically located on the left side of the kart, i.e. a kart brake is operated with the left foot, which takes some getting used to. The pedal itself is typically quite simple, often not more than a thin, bend metal bar, secured with only one simple joint on the frame. The pedal is connected to the master cylinder via the brake tie rod.

Brake rotor

A different name for brake disc.

Brake tie rod

The brake tie rod connects the brake pedal to the master cylinder via the clevis. It essentially trasmits the movement of the brake pedal to the brake system. The brake tie rod is also called the control rod or the brake actuating rod. Also see tie rods.

Briggs

Manufacturer of a 4-cycle engine used in some karting classes.

Bumper

The front and back of the frame is protected by additionally mounted metal bars, the bumpers. These bumpers are adding a few inches to the length of the kart. Their height and length may be regulated. If the kart is equipped with front nose, this nose is mounted onto the front bumper. A number plate is typically attached to the rear bumper.

A kart with a roll cage and seat belts. Most popular on ovals.

Calipers

The calipers are located inside of the slave cylinder. The brake pads are mounted to them. The calipers are moved via hydraulics which in turn presses the brake pads onto the rotating brake disc.

Cam shaft

In 4-cycle engines the opening and closing of the intake and exhaust valves is controlled by the cam shaft. The cam shaft rotates over the end of the valves, periodically pressing them close via excentric lobes. Please click here for a great explanation.

Camber

Camber is the number of degrees that the top of the tire is tipped inward (negative camber) or outward (positive camber). It affects handling. Most karts will have some negative camber. Depending on the frame it might be adjustable by repositioning the kingpin. See there for more details.

Can

A short name for the 'can type' of exhausts used in many karting classes. These are typically either the sportsman can or the super sportsman can (SSX).

Carb

Short for carburetor.

Carburetor

A devcie which mixes the fuel with oxygen before it enters the cylinder in which it will eventually detonate. This mixing is necessary, since without oxygen there would be no explosion, or burning. The carburetor which is mandated on most classes which utilize the KT-100, is the Walbro. See carburetor pulse line.

Carburetor pulse line

A hose that carries the pulse signal, which operates the fuel pump.

Carburetor setting

The combined settings of the high-speed needle and the low-speed needle, which determines the ratio of the fuel - oil mixture.

Caster

Caster is the amount of degrees the top of the kingpin leans towards the rear of the kart. On some frames this is adjustable. It affects handling. Check out the description of kingpin for more information.

Cassettes

The bearings of the rear axle are mounted into the axle cassettes, which in turn are mounted into the journals of the frame. The cassettes are typically solid metal pieces, machined to provide a snug fit for the bearings.

Chain

The chain connects the sprocket on the engine to the sprocket on the rear axle. When the rear sprocket is changed, the length of the chain needs to be modified. Special tools are needed to mount and unmount a chain, most notably the chain breaker. The chain needs to be taken care of by applying some kind of lube. Which lube is the best is also a topic of heated discussion. There are different kinds of chains, which are distinguished primarily by the number of links per foot. E.g. the #219 chain has 39.2 links/foot, the #35 chain has 32, the #40 chain has 24 and the #520 has 19.2. The very first number of the chain designation indicates the size of a link (called a pitch), in 1/8th of an inch. E.g. in a #35 chain, the pitch size would be 3/8th of an inch, in a #520 chain it would be 5/8th of an inch, etc. The #219 is an exception, though, it's pitch size is 2.45/8th. The subsequent one or two numbers are used to distinguish even more details of the chain, e.g. characteristics of the pin, thickness of the plate, etc. A specific sprocket will therefore require a specific chain, since the gap between the teeth determines the pitch size which is applicable. The finer the teeth, the more gear ratios can be tried without varying the size of the driven sprocket too much. The #219 chain is the chain with the smalles pitches, hence it will allow the use of more fine-teethed sprockets. A popular variety is the '#35 space chain'. See also oiler.

Chain alignment

The term is actually a little bit misleading. What is meant is the correct alignment of drive gear and driven gear such that they are located in the same plane. Otherwise the chain would have to run 'around a corner' so to speak.

Chain breaker

A very handy and necessary tool which allows you to link and unlink the chain. By tightening a screw, the pin which holds to chain links together can be removed or re-inserted.

Chain guard

A curved metal or plastic shield, connected to the engine on one end and the frame on the other end. It is located above the chain, and prevents oil to be flung from the moving chain onto the driver. More importantly, it protects the driver from metal shrapnels entering his/her body in case of a broken chain!

Chassis

See frame.

CHT

The Cylinder Head Temperature is measured and displayed on a temperature gauge. If the temperature gets to high, the driver may have to richen the fuel. If it is not hot enough, the driver makes the Fuel leaner, i.e. increases the air to fuel ratio. Good temperatures for the KT-100 are 325 to 350 degrees (F).

CIK

Commission Internationale de Karting. French for 'International karting committee', an international karting governing body.

Classes

Kart racing is done in classes, i.e. only karts belonging to a specific class will race against each other. There is a huge variety of classes, which is typically quite confusing to a beginner. Apart of novice classes and senior classes, classes which differentiate according to the weight of driver and kart, there are also various 4-cycle and 2-cycle classes, classes which differentiate according to engine manufacturer, different exhaust systems, different kinds of tires, direct drive or clutch etc. The most common classes in 2-cycle racing are novice sportsman, sportsman, super sportsman, pipe (a.k.a. KT-100) and the direct drive class Formula-Y. For a beginner, it is important to see which class is popular on the local race tracks, since you want to compete against more than just one or two others.

Cleaners

Various more or less poisonous substances which are used to remove dirt buildup, oil, grease and other stuff from parts and engine.

Clevis

A small component which threads onto the brake tie rod and connects the rod to the master cylinder.

Clutch

The clutch allows the engine and drive wheels to be disconnected (such as when idling at a stop) when disengaged, and the engine and rear wheels to be connected when fully engaged. Shifter karts have a manual clutch that must be engaged/disengaged manually by the driver, other clutches automatically engage or disengage (slip) based on the engine RPM. This stall speed can be changed (modifying the clutch) and therefore is part of the setup. Well known manufacturers of clutches are Horstman and L&T.

Clutch holder

The holder holds the hub assembly of the clutch so the starter nut can be removed. This tool might be specific to the brand of clutch you are using.

Clutch lining

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Clutch oil

A special oil used to lube the inner parts of a wet clutch. It needs to be checked and replenished regularly (after every race). Oil may leak out of the clutch, which makes wet clutches just a tad messy.

Clutch puller

A tool which is necessary to unmount a clutch. The puller removes the hub from the crankshaft. This tool might be specific to the brand of clutch you are using.

Clutch tool

Compresser, adjuster

Compound

Various types of tires will use different compounds, i.e. rubber mixtures. The compound determines the stickyness of the tire.

Compression gauge

A tool to measure the pressure in the cylinder at the top end of travel of the piston. Comparing this pressure to the baseline which was established for this kind of engine can give indications of the internal conditions of the engine. Low compression usually means poor performance. The tool is inserted in the slot for the spark plug after the plug was removed.

Computer

These days more and more kart racers use computers to analyze their lap times and other data, just like the professional racing teams. Of course, the right software is needed. Computers are heavy equipment, so it is advantageous if the software runs on small and portable computers as well, e.g. the Lap Tracker which also runs on the Palm Pilot.

Connecting rod

A metal rod inside of the engine which connects the crankshaft to the piston. Having this rod break in a running engine would result in major damage, which is just one more reason to have your engine regularly re-built. The purpose of the connecting rod is to translate the up-and-down motion of the piston into the rotational motion of the crankshaft

Contact patch

The area with which a tire makes contact with the road surface. The larger the contact patch, the more grip the tire will develop. The size of the contact patch is also determined by the load on the tire.

Control rod

A different name for brake tie rod.

Cordura

An abresion resistant material which is used to manufacture the karting suit and potentially also the gloves and shoes. It is not fire resistant, but it potects when the driver is scrubbing over the ground after an accident.

Cotter pin

A pin made from a thick wire, folded such that one end of the pin will have two wire ends. The pin can then be used for the same purpose as safety wire, by bending the two wire ends apart, after the pin has been inserted into the hole, such that the pin can not slip out anymore.

Crank case

The part of the engine which houses the rotating crankshaft. On 2-cycle engines which use the reed valve or rotary valve principle, it also contains the intake for the air - fuel mixture. The crank case is located inside of the sump.

Crankshaft

The axle which sticks sideways out of the engine and which is turned, potentially thousands of times a second, by the up-down motion of the piston inside of the cylinder. The piston is connected to the crankshaft via the connecting rod. The clutch typically mounts on the crankshaft, outside of the engine.

Cross weight

In oval racing the weight is not evenly distributed across the frame since some wheels have to carry much more load than others. The percentage of weight on the right front vs. the left rear wheel is called the cross weight.

CRG

Manufacturer of a 2-cycle engine used in some karting classes.

Cylinder

Part of the engine in which the piston is moving up and down. The detonation of the air - fuel mixture takes place in the cylinder. The cylinder end in the crank case at the bottom and the cylinder head at the top.

Cylinder head

A part of the engine which is mounted on top of the cylinder. In effect, it is the 'lid' on the cylinder. The cylinder head houses the spark plug and (on 4-cycle engines) the valves. The cylinder head is mounted to the cylinder by 4 to 6 screws, which need to be tightened very carefully in order not to damage the head. The cylinder head on air cooled engines is equipped with fins for cooling. The Cylinder Head Temperature (CHT) is measured and displayed on the temperature gauge.

Karting without a clutch. The crankshaft is directly connected to the rear axle via the chain. Thus, the kart engine cannot run when the kart is not in motion. A direct drive kart needs to be push-started. Since you don't need a starter or a clutch, some people claim that it is actually a less complicated and less expensive way of driving. The direct drive classes (e.g. Formula-Y) are typically quite fast. While in the US direct drive tends to be more exotic, in the rest of the world direct drive is standard.

Dirt tires

Contrary to slicks, dirt tires have a profile which is useful when racing on mud, sand or dirt. See dirt oval.

Dirt oval

As the name implies, dirt racing on an oval track, made from dirt or clay. See speedway.

Dirt racing

Racing on dirt (sand, clay, mud) as compared to asphalt racing. Special dirt tires are used. The kart setup may differ significantly from asphalt racing.

Display

Another name for the gauges which are typically attached to the steering wheel.

Draft

A fast moving racing vehicle will create an area of low pressure, a relative vacuum, behind it. Another vehicle can use this low pressure area to its advantage, since in that area the air resistance is reduced, i.e. it will be able to go faster, gaining on the leading vehicle. The first vehicle is said to produce a draft. Also see drafting. It should be noted that for slower classes of racing (i.e. many classes of sprint karting), draft is not much of an issue. The effet is more pronounced in faster kinds of racing (F1, CART, IRL, NASCAR, etc.).

Drafting

When a vehicle takes advantage of another vehicle's draft and thereby manages to either keep up with or even gain ground on the leading vehicle which is producing the draft. The second vehicle is said to be drafting. It is interesting that a drafting vehicle even increases the speed of the leading vehicle somewhat. The trailing vehicle's presence in the relative vacuum produced by the first vehicle will straighten out the air turbulences behind the leading vehicle. These turbulences would otherwise have slowed down the leader. Thus, especially in NASCAR races in can often be observed that several vehicles forming a train are moving faster than an individual vehicle. In most classes of karting drafting is not a big factor due to the relatively low speed.

Drive gear

Other name for drive sprocket.

Drive sprocket

The small sprocket mounted on the outside-portion of the crankshaft. It is connected via the chain with the driven sprocket. Also called the drive gear. See also gear ratio.

Driven gear

Other name for driven sprocket.

Driven sprocket

The larger sprocket mounted on the rear axle. It is connected via the chain with the drive sprocket. Also called the driven gear. The size of the driven sprocket is measured in teeth. See also gear ratio.

Drivers meeting

The drivers' meeting is where the participants ona race day are briefed about club rules and regulations. It is very important to attend this meeting since one might also receive information about schedule or rule changes.

Dry clutch

A kind of clutch which does not rely on oil for heat dissipation like wet clutches. A dry clutch is lighter and offer less resistance friction. At the same time, they might burn out more easily than wet clutches. Wet clutches are also typically used in heavier classes. Dry clutches are also most suitable for lighter, slower classes.

Duct tape

A commonly used type of sticky-tape which holds racing vehicles together in pretty much all forms of racing.

Durometer

A device use dto test the stickyness of tires. It is usually applied during tech inspection right after the race has been completed, to see whether a competitors tire does not exceed the legal amount of grip.

Dynamometer

Also called 'Dyno'. A machine which allows the engine builder to measure the torque and horsepower of an engine.