Gaskets, Seals & O-Rings
About Gaskets, Seals & O-Rings
Gaskets, seals and O-rings keep oil, fuel, air and coolant where they belong at the joints between parts. Riders buy them when a cover, base or flange weeps oil, when a carburetor or intake joint leaks air, or when an engine, carburetor or primary drive is apart for a rebuild and every joint gets a fresh seal. Most gaskets are made to be used once, so a part that comes off usually needs a new one.
Start with what you are sealing. Top end gasket kits, such as those for KTM, Husqvarna and Gas Gas engines, cover the cylinder joints and come with different base gasket types, including fiber and rubber-coated steel. Carburetor gasket kits and diaphragm kits are listed by carburetor and model, shaft seals protect where a rotating shaft leaves a case, and O-rings are sold by size. A listing such as 2 inch ID by 2.125 inch OD tells you what to match. Viton, a fluorocarbon rubber, tolerates heat and fuel well.
Match the kit to your engine model and year, or use the Ride Finder at the top of the page. Brands here include Vertex, Colony, Drag Specialties, S&S Cycle and Cometic. Gaskets often go with Carburetor Parts, Fuel Tank Caps or Manifold Intake Adapters, Inlets & Joints, all within Air Intake & Fuel Delivery. A few other parts, such as Ski-Doo torsion spring spacers, are also filed here, so read each listing.
FAQs on gaskets, seals and O-rings
Can I reuse a motorcycle engine gasket?
Usually not. Paper, fiber and rubber-coated gaskets compress to the shape of the joint when tightened, and they rarely seal as well a second time. If the part has been removed, fit a new gasket and clean both mating surfaces of old material first.
How do I find the right O-ring size?
Measure the inside diameter, the outside diameter and the thickness of the ring's cross section, or read them from the old ring if it is not swollen or damaged. Sizes are often listed as ID by OD, and standard dash numbers such as -033 also identify them. Match the material to the fluid it will touch.
What is a Viton O-ring used for?
Viton is a fluorocarbon rubber that tolerates heat and many fuels and oils better than standard rubber. It is a common choice where an O-ring sees fuel, hot oil or high temperatures. Check the listing's material and size against the original before you buy.
Do I need gasket sealant with a new gasket?
Many gaskets are installed dry, and some call for a thin film of sealant in specific spots, such as case joints. Your service manual says which. Do not add sealant where the maker does not call for it, because the excess can break loose and block passages.
What does a top end gasket kit cover?
A top end kit generally holds the gaskets and seals needed when the cylinder head and cylinder come off, including a base gasket, with the other pieces varying by model. Kits are not interchangeable between engines, so compare the listing's contents with what your engine needs.
