Throttle Bodies
About Throttle Bodies
A throttle body meters the air that enters a fuel-injected engine. A plate inside opens as you twist the grip, and the injector adds fuel to match. Riders look at this category to replace a damaged throttle body or to move to a larger bore as part of an engine upgrade. A guard is also listed for certain Gas Gas, Husqvarna and KTM models, to shield the unit.
Bore size is the main spec. Listings show 51, 55, 58 and 66 mm, with Twin Cam fitments among them, plus a 70 mm induction kit for Touring models. A larger bore moves more air, but it pays off only when the intake, exhaust and engine can use it, and it needs a matching tune. Check how the throttle is operated, because some kits here are cable operated, and confirm that the controls on your bike suit the kit. A Polaris throttle body also appears. Match the model and year, or use the Ride Finder at the top of the page.
Brands here include S&S Cycle, Horsepower, Inc, Moose Offroad and Tecmate. A throttle body works with Fuel Injectors, Air Filters and Air Filter Housings, and the wider group is Air Intake & Fuel Delivery.
FAQs on motorcycle throttle bodies
Does a bigger throttle body add horsepower?
Only when the rest of the engine can use the extra air. A larger bore works together with the intake, exhaust, cams and tune, and on its own it may make no noticeable difference or dull low-speed response. Follow the kit maker's listed combinations for your engine.
What size throttle body does my engine need?
It depends on the engine's displacement, the intake manifold and air cleaner, and how the engine is modified. Bigger is not always better, because an oversized bore can hurt low-speed response. Choose the size the kit maker lists for your engine and setup.
Do I need a tune after installing a new throttle body?
Usually yes. The engine computer is calibrated for the original airflow, and a different bore changes it. Many kits call for a fuel map update or a tuner. Read the kit's instructions, and have the tune done before regular riding.
Can I clean a throttle body instead of replacing it?
Often. Carbon and varnish around the throttle plate can cause a rough idle, and a cleaner made for throttle bodies can remove it. Follow your service manual, because some bores have coatings and electronic throttle plates should not be forced open by hand.
Will a throttle body from another model fit my bike?
Probably not. Flange shape, bore, sensors and linkage differ between models and years. Use the fitment named in the listing, and pick your machine in the Ride Finder to see throttle bodies made for it.
