Fuel Tank Caps
About Fuel Tank Caps
A fuel tank cap seals the filler opening to keep fuel and vapor in the tank and, on a vented design, lets air in as fuel is used. Riders replace caps that are lost, cracked, leaking at the seal or stuck, and many add a locking cap for security or a billet or colored cap for looks.
The most important choice is vented or non-vented. A vented cap has a path for air to enter. A non-vented cap relies on a separate vent or vapor system on the bike, so fitting the wrong type can starve the engine of fuel or trap pressure in the tank. Use the type your bike was designed for. Then decide on locking or non-locking and on the finish; chrome, gloss black, aluminum and colored caps all appear here. Cap and filler neck styles differ by make and model, so pick your bike in the Ride Finder at the top of the page.
Brands here include Mustang, Vortex, UFO, EPI and Drag Specialties. A few listings are related tank items, such as large-capacity gas tanks for certain KTM, Gas Gas and Honda models. If a cap only leaks at the rim, a new gasket from Gaskets, Seals & O-Rings may be all it needs. Also see Fuel Tanks, Fuel Petcocks & Taps and the wider group, Air Intake & Fuel Delivery.
FAQs on motorcycle gas caps
What is the difference between a vented and a non-vented gas cap?
A vented gas cap lets air into the tank as fuel is used, so fuel keeps flowing to the engine. A non-vented cap seals the tank and depends on a separate vent line or vapor system on the bike. Check which type your bike uses before buying, because they are not interchangeable.
Can the wrong gas cap make a motorcycle stall?
Yes. A non-vented cap on a bike that relies on a vented cap, or a blocked vent, can let a vacuum build in the tank until fuel flow drops and the engine stumbles or stops. If loosening the cap briefly restores normal running, that points to a venting problem.
Is a locking gas cap worth it?
A locking cap makes it harder for someone to open the tank to siphon fuel or tamper with it. Keep a spare key somewhere other than on the bike, because a lost key can mean replacing the cap, and check that the cap seals fully after each fill.
Will a gas cap from another bike fit mine?
Often not. Filler neck size, thread or bolt pattern and cap shape differ by make and model, and a cap that sits wrong may leak. Use a cap listed for your bike, and check the Ride Finder at the top of the page for matching listings.
What should I do if fuel leaks around the gas cap?
Check the cap's rubber seal and the sealing surface on the filler neck for cracks, dirt or flattening. A worn seal can often be replaced on its own, but a cracked cap should be replaced. Do not ride with fuel leaking, because fuel on a hot engine is a fire risk.
