Troubleshoot A Motorcycle Air Intake Boot

Air intake boots connect between the carburetor and air filter.

Motorcycle air intake boots are short sections of rubber or composite duct that connect between the carburetor intake and the air filter. Like a lot of parts on a motorcycle, air intake boots are subject to the effects of heat, oil, water and dirt. Cracks or punctures in a boot can affect the volume of intake air to the carburetor, resulting in performance problems. Many riders overlook the boot and replace the air filter or attempt to adjust the carburetor to correct performance issues. Troubleshooting the air intake boot on your motorcycle helps to isolate the source of problems.


1. Locate the clamps that secure the boot to the carburetor intake and the air filter. Depending on the motorcycle, it may be necessary to remove the seat to access each end of the boot and the clamps. Your repair manual should have carburetor and air cleaner service procedures that include this information.

2. Tighten the boot clamp at the carburetor and the air filter by turning the clamp screws clockwise with a metric nut driver or screwdriver.

3. Start the motorcycle and let it warm up for two minutes. Minor air-volume problems are harder to isolate when heavier, cool air is drawn into the system.

4. Twist the throttle handgrip several times when the engine is warmed up. A crisp response suggests one or both of the clamps were loose. Any delay or stumble in acceleration indicates another problem.

5. Turn the engine off. Loosen both clamp screws counterclockwise with the nut driver. Work each end of the boot off the air cleaner and carburetor by hand and remove the boot.

6. Inspect the boot thoroughly for cracks or punctures. Put one or two tablespoons of water in the boot and roll the boot by hand as you look for small leaks. Replace the boot if you find a leak or crack. When no damages are found, set the boot aside.

7. Start the motorcycle and twist the throttle several times. A crisp response indicates a clogged or dirty air filter is inhibiting the volume of air-flow. A poor throttle response indicates a problem with the carburetor.