3 Motorcycle Fuel & Air Parts that Need Cleaning

A motorcycle’s performance depends a lot on having the proper air-fuel ratio (known as the Stoichiometric ratio) to keep it from running too rich or lean. 

Dirty or clogged fuel and air parts can negatively affect this delicate ratio, and cause a whole slew of other problems with your motorcycle. Preventing problems with the air-fuel mixture sometimes only requires the cleaning of certain parts. Here are 3 motorcycle fuel and air parts that need to be cleaned to help prevent engine combustion problems.

Rich vs Lean 

Before we get into the parts, let’s talk about rich running vs lean running engines. When tuning a motorcycle, it’s important to determine whether it’s running too rich or too lean on the ratio of fuel to air inside the combustion chamber, and adjust it accordingly. 

A rich running engine simply means there’s too much fuel in the mix. The percentage of air is too low, and the percentage of fuel is too high, which results in incomplete combustion. A lean running engine simply means there’s too much air and not enough fuel in the mix, and therefore the combustion doesn't pack enough punch to get full power. 

Cleaning or replacing fuel and air parts such as carburetors and air filters can help resolve problems with an engine running too rich or too lean. 

Clean the Air Filter

Cleaning and/or replacing the air filter is one of the most important routine maintenance jobs you can do. But only reusable foam and fabric air filters are meant to be cleaned and reused, not disposable paper filters. 

When the air filter gets clogged, it restricts air flow, making the engine start to burn too much fuel. Signs that an air filter is clogged include fouled spark plugs, hard starts, sluggish throttle, and black exhaust smoke. 

If left unattended, a dirty air filter will eventually fail to keep contaminants out of the engine. And if the engine doesn’t get enough clean air, it loses power and performance. Dirt, debris and grime can build up to the point that clean air no longer passes through the filter, so it needs to be cleaned or replaced. 

Clean your motorcycle’s reusable foam or fabric air filter with quality air filter cleaners and filter oils regularly to protect the engine and improve gas mileage.

Clean the Carburetor

On carbureted motorcycles, a day will come when you have to either clean, rebuild or replace a carburetor. Because no matter how well you take care of your bike, the carb will eventually get dirty and build up gunk left by evaporated fuel and other contaminants that make their way into the fuel system.

Clogged carburetor jets prevent the proper fuel and air mixture from entering the cylinder, which can lead to major issues. When carburetor jets get blocked, the amount of fuel reaching the carb is reduced, impairing a motorcycle’s performance if left unchecked. Clogged jets are often the result of stale fuel sitting in the carb when the motorcycle is inactive. Stagnant fuel leaves a gummy residue behind, and if the carb gets clogged, it'll prevent the bike from running properly. 

Cleaning the carburetor is essentially disassembling the carb, spraying it with and/or soaking it in carb cleaner, and scrubbing off dirt and grime to eliminate problems like rough idling, engine bogging and other performance issues.

Clean the Fuel Injectors

On fuel-injected motorcycles, the injectors help deliver the correct fuel-to-air ratio to the engine to ensure a clean burn and maximum power. 

The ethanol found in modern fuels can create varnish-like deposits within the spray tips of the fuel injectors. Dirt and other contaminants affect the fuel injectors’ ability to do their job, which in turn messes up the fuel-to-air ratio. Symptoms of dirty or clogged fuel injectors in a motorcycle include loss of power, poor idling and increased fuel consumption. 

Clean the fuel injectors at least once every three years, but even sooner if your motorcycle sat too long, or if the injectors show any symptoms of being dirty or clogged.

Another problem that could be caused by dirty or faulty fuel and air parts is a motorcycle only running on choke, due to poor internal combustion. Watch the video below to learn how to troubleshoot problems with an engine that only runs on choke.