Manifold Intake Adapter, Inlet & Joint
About Manifold Intake Adapter, Inlet & Joint
The intake manifold, or inlet, is the passage that carries the air and fuel mixture from the carburetor to the cylinder, and the joint is the seal where the two meet. Owners replace one when the rubber hardens or cracks and lets air leak in, or when a larger carburetor needs a matching manifold.
Match the manifold to the carburetor. Several listings here state the carburetor size in the title, such as a 44 mm Yamaha manifold or a manifold for 34/36 mm carbs on a Banshee, and the bore and flange have to match the carburetor you are fitting. Other listings include a carburetor mounting flange and a fuel inlet seat for an S&S carburetor. A leaking manifold lets in extra air, which leans out the mixture and can cause a high or surging idle and hard starting. Fittings sold as CarbMate/VacuumMate come in M5 and M6 sizes, so match the thread size to the port in your manifold. Changing the carburetor or manifold can also change jetting, so follow the carburetor maker's setup guide.
Brands here include Mikuni, S&S Cycle, Bikeman Performance, Moose Offroad and Modquad. Replace the seals while the joint is open, using Gaskets, Seals & O-Rings. Related groups are Carburetors and Carburetor Parts. The whole group is Air Intake & Fuel Delivery.
FAQs on intake manifolds and carburetor joints
What does an intake manifold do on an ATV or UTV engine?
The intake manifold connects the carburetor or throttle body to the cylinder head and carries the air and fuel mixture into the engine. It has to be sealed against air leaks, because extra air entering after the carburetor changes the mixture.
How can I tell if my intake manifold is leaking?
Look for cracks, a hardened or split rubber boot and loose clamps. Symptoms of an air leak include a high or hunting idle, hard starting and a lean-running engine that may pop or overheat. Check the manifold and its seals before changing carburetor jets.
Do I need a new manifold if I change carburetor size?
Often yes. The manifold bore and mounting flange must match the carburetor, and listings here name sizes such as 44 mm and 34/36 mm. Check the carburetor maker's fitment notes for your model, since a mismatch can restrict flow or leave a gap.
Should I replace the gasket or O-ring when I change the manifold?
Yes. Fit new seals whenever the joint is opened, because old ones harden and flatten and can leak. A leak at this joint lets in unmetered air and upsets the mixture. Tighten the clamps and bolts evenly, following your service manual, so the manifold seats flat.
