Fuel Tank Caps
About Fuel Tank Caps
The fuel cap seals the filler opening, keeps fuel and vapor in the tank and lets the tank vent as the fuel level drops. Riders replace one that is lost, cracked or leaking, or choose a new style to match custom parts.
Caps here are listed in a few styles, including pop-up caps and 12 point caps, in finishes such as chrome, black, red, blue, gold and carbon fiber. Fit comes first. Caps are made for a specific thread and tank opening, and the titles name machines such as Can-Am, Triumph and Harley-Davidson models, so match the listing to your machine, not just the look. Whatever the style, the cap has to seal and vent as the original does. A cap that does not vent properly can starve the engine of fuel, and one that does not seal can leak fuel and vapor, so use only a cap listed for your model.
Brands here include Arlen Ness, Acerbis, Paul Yaffe Bagger Nation, Moose Offroad and Emgo. If you are replacing the tank hardware, also see Fuel Tanks and Fuel Valves & Petcocks. The whole group is Air Intake & Fuel Delivery.
FAQs on fuel tank caps
Will any gas cap fit my machine?
No. Gas caps differ in thread, diameter and venting design, so a cap has to be listed for your model. Check the listing for your machine and year, or pick your machine in the Ride Finder, instead of choosing on appearance alone.
Does the style of a gas cap matter, or only the fit?
Style is mostly a matter of looks, as long as the cap fits the tank opening, seals and vents the way the original does. Pick the finish you like from caps listed for your model, and avoid a cap that is only said to be similar.
Why does my gas tank hiss or run out of fuel when I open the cap?
A hiss when you open the cap is normal pressure release. If the engine starves for fuel and recovers when you loosen the cap, the vent may be blocked, which can be the cap itself or a hose. Check the vent and clean or replace the part.
How do I know if my fuel cap needs replacing?
Replace a cap that has a cracked or hardened seal, will not tighten, leaks when the machine tips or smells of fuel. Never ride with a cap missing or loose, because fuel can spill and water and dirt can enter the tank.
