What Happens When Air Filters Clog on Motorcycles?by Chris Gilliland
A motorcycle's air filter is designed to allow as much air into the engine's intake as possible, while screening out harmful dirt and debris. This detritus can build up across the filter's paper, mesh or fiber element and eventually prevent air from flowing through the filter. If left as is, a clogged air filter can causes serious engine damage or a loss of performance.
How An Air Filter Works
A typical motorcycle air filter consists of a filtering element that is supported by a light plastic or rubber frame. The element itself can be made from several different materials, ranging from folded paper, cotton fiber, wire mesh or foam. Some materials provide better air flow and reusabliity, while others are more durable or cheaper to manufacture. In either case, the filter allows air to pass though the element, trapping large dust particles and road debris in the element. Some air filters have an additional coating of oil on the element's outer face to further reduce dust infiltration.
The Effects of a Clogged Air Filter
As an air filter clogs, it reduces the amount of air that is pulled into the engine intake system. This creates an imbalance in the air-to-fuel ratio that powers the engine and creates a rich-running condition, where there is more fuel than air. The lack of air prevents the fuel from igniting completely during the engine's combustion phase, reducing the engine's power output. Immediate symptoms are seen as decreased fuel economy, sluggish throttle response and a loss of power. If the air filter continues to collect dirt to the point of total clogging, the engine will not be able to ignite the fuel at all.
Clogged Air Filters and Motorcycle Cooling Systems
The air-to-fuel imbalance created by a clogged air filter can cause also problems with your motorcycle's cooling system. The addition of fuel into the air-fuel ratio reduces the total heat of combustion within the engine. As air is eliminated from the mixture, the temperatures drop. This can prevent your motorcycle's engine from reaching the fully warmed-up state where it will perform best.
All motorcycle manufacturers provide a Table of Periodic Maintenance in the motorcycle's owner's manual and service manual. This details maintenance procedures that must be performed at specific mileage intervals. You must check your air filter often, using this interval as a guide, to ensure that the filter allows enough air into the engine. You may need to inspect and clean or replace your air filter more frequently if you have been riding in extremely dusty or dirty conditions. In most cases, a paper element filter should be replaced as soon as dirt buildup is evident. However, light buildup can sometimes be shaken free. Foam, mesh and cotton filters may often be washed and re-oiled for use, following the directions provided by the filter's manufacturer.
- "Haynes Motorcycle Workshop PracticeTechbook"; John Fidell; 1999
- "Modern Motorcycle Technology: How Every Part of Your Motorcycle Works"; Massimo Clarke; 2010
- "The Professional Motorcycle Repair Program"; Professional Career Development Institute; 1995
An avid motorcyclist, Chris Gilliland has immersed himself into the two-wheeled world while balancing work life and raising three daughters. When he is not managing the parts department of a local, multi-line motorcycle dealership, Gilliland can often be found riding, writing or working on his motorcycle blog, Wingman's Garage.