Parts of a motorcycle: the basis

Knowing the parts of a motorcycle is something that should be in the arsenal of every biker. You should not be a professional mechanic but, knowing the basics will definitely help you take the right decision when it comes to deal with issues and/or buying aftermarket parts. Keeping in mind that motorcycles can vary in design for several factors, but share the same basic anatomy, let’s talk a bit of the basics.

Engine

The engine is among the parts of the motorcycle that are essential to define a motorcycle as a motorcycle.

Almost all motorcycles on the market are equipped with conventional internal combustion engines. However, companies are starting to produce electric powered motorcycles.

The most common configurations nowadays are:

• Single
• Twin in line
• V-twin
• Boxer
• Triple in-line
• Four in-line
• V-Four

Engines with more cylinders for the same displacement make it easier to ride, while engines with fewer cylinders are cheaper, lighter, and easier to maintain.

Configuration is not the only trait that distinguish an engine, there also are the number of strokes and the way it is cooled:

• A liquid-cooled engine consists of a radiator which is the primary way their heat is dissipated. Coolant continuously circulates between the radiator and the cylinders when the engine is running. These engines have the potential for greater power at a given displacement, closer tolerances, and longer operating life.

• An air-cooled engine depends on air blowing and heat dissipation. These are cheaper to buy, less mechanically complex, and lighter. An air-cooled engine shrinks and expands along its wide temperature range requires looser tolerances, and gives shorter engine life. In order to improve it, an oil radiator is usually added.

• A two-stroke engine is lighter and much simpler mechanically. It produces more power when operating at its best. Most modern two-strokes are single-cylinder, liquid-cooled, and under 600 cc.

• A four-stroke engine is cleaner, more reliable, and provide power over a broader range of engine speeds.

Needless to say, motorcycle companies play with all these options to create motorcycle engines that can perform and provide a motorcycle model that can satisfy the needs of each motorcycle segment.

Transmission, clutch lever and shifter

These are the parts of the motorcycle that make movement possible.

When the rider pulls the clutch lever, the clutch spring contracts, causing the pressure plate to retract. This splits the friction and steel plates, so they spin freely. Thus the clutch disconnects the engine from the transmission. Therefore, the power to the rear wheel is stopped, and the gears can be changed thought the use of the gear shifter.

Frame

The frame is a bit different from the parts of the motorcycle that we have seen so far: it is the main structure of a motorcycle. This part is so important that by itself defines the motorcycle category, its design can make the motorcycle super easy to ride or a real pain in to go around with.

It is usually made of aluminum, but some premium motorcycles might have Carbon fiber, titanium, or magnesium frames.

Suspensions

These parts of the motorcycle make it possible to ride. The front fork is the most crucial part of handling the motorcycle. The combination of rake and trail in the front fork define the motorcycle behavior.

Forks have yokes that hold the fork tube (which contains the fork springs and oil) and are fastened by the steering stem to the neck of the frame. The lower legs of the forks are known as sliders that hold the damping assemblies. The front axle is positioned vertically and engages the sliders. The handlebars are attached to the top triple tree, allowing the rider to steer the motorcycle.

The rear suspension of the motorcycle uses a spring and damper combination to isolate the chassis and rider from road defects. Motorcycles can use a single shock absorber or a double rear suspension, which connects the rear swingarm to the motorcycle’s frame.

Usually, this shock absorber is in front of the rear wheel and uses a linkage to attach to the swing arm. The design of the rear suspension can be very different compared to the front suspension. It works with the front suspension to reduce road or trail impact. Some old motorcycles sport a rigid frame, therefore do not have a rear suspension.

Rims and tires

Rims and tires are the parts of the motorcycle that allow motion.

Wheel rims are made of steel or aluminum (usually with spokes and aluminum hub), mag-type cast, or machined aluminum. A rim is the frame of a tire that holds the force and tension caused by the vehicle’s weight and the effects of various road conditions.

The manufacturers have carefully considered and enhanced the safety of the rim to prevent any accidents due to rim failure or deformation. Proper fitting between the tire and the rim is essential for tubeless tires to seal the air. Older models had inner tubes between the rim and the tire.

Tires also play an important role as they are the only link between the vehicle and the road. A tire not only transmits the motor’s power to the road but also absorbs shocks from uneven road surfaces.

In addition, it supports the vehicle’s weight and transmits accelerating and braking force to the ground. Your safety depends not only on the maintenance of the tires but also on the choice of tires. Checking your tire pressure to ensure they are correctly inflated can make a real difference in how long your tires last.

Brakes

As you know, these parts of the motorcycle represent a rather important safety feature. Motorcycles typically have two independent brakes, one on the front wheel and one on the rear. Nevertheless, some models have “linked brakes,” whereby both can be applied simultaneously using only one control.

Their work is fairly easy to understand: pulling the brake, the force on the levers is transferred through an incompressible fluid to the caliper pistons, which then press the brake pads against the discs. Disc brakes and drum brakes are two braking systems used in today’s motorcycles:

• Disc Brake: Disc brakes are widely used in motorcycles, some brands use only one disk in the front, especially in the cruiser segment. Sport bikes, naked bikes and large bikes usually sport a double front disk set-up.
• Drum Brake: These brakes were used regularly before the invention of disc brakes.

Tank

The funny think about the tank is that among all the parts of the motorcycle, it is the most misunderstood one: most people thing that the function of the fuel tank is to hold fuel only. However, it has an important role in helping the rider controlling the vehicle (especially on sportbikes). It also provides a safe area for knees to hold while riding, which is an essential point of contact between bike and rider.

Motorcycle fuel tanks usually hold about 1.5 – 8.5 gallons of gas, but most have a gas tank with 3 – 6 gallons capacity.

Our trip into the essential parts of the motorcycle is over. If you are a newbie, we hope it was helpful. If you still have any doubts or questions, please let us know in the comments.