Gaskets, Seals & Kits
About Gaskets, Seals & Kits
Gaskets and seals keep oil, coolant and combustion pressure where they belong, and they are replaced whenever the part they seal has been opened. Riders shop here to stop a leak at a cover or head, to reassemble an engine after a rebuild, or to refresh sealing parts at the same time as other work.
Kits come in three scopes. A single gasket, O-ring or seal covers one joint, such as a dipstick O-ring or a top cover gasket. A top-end gasket kit covers the cylinder and head and is a common purchase for dirt bikes and Japanese models. A complete gasket kit covers the whole engine. Listings are named by model, for example Honda, Kawasaki, Yamaha or KTM and Husqvarna, and Harley-Davidson parts by engine family, such as M8 and Evolution. Head gaskets list a bore size, such as 4.320 inch or 68 mm, which must match your cylinders. Some gaskets need sealant and some are installed dry, so follow the instructions.
Brands here include Athena, Cometic, BBR Motorsports, Cylinder Works and Colony. For more of the rebuild, see Engine Rebuild Kits & Components, Cylinder Heads and Engine Covers. Pick your machine in the Ride Finder at the top of the page.
FAQs on engine gaskets and seals
Should I buy a top-end gasket kit or a complete gasket kit?
A top-end kit is enough if you are only working on the cylinder and head. A complete kit makes sense when the engine cases will be split. Read the contents list, since kits for different models include different parts.
Can I reuse an old gasket?
It is not recommended. A used gasket has been compressed and may have hardened, so it can leak after reassembly. O-rings and seals should be replaced for the same reason, particularly when the cost is small.
Do I need gasket sealant when I fit a new gasket?
Only where the service manual or the gasket maker calls for it. Some gaskets go on dry, and too much sealant can squeeze into oil passages and block them. Follow the instructions for your model.
How should I prepare the surfaces before fitting a gasket?
Remove the old gasket material with a plastic scraper or similar, avoiding gouges, and clean the surfaces with solvent. Both mating faces should be flat, clean and dry before the new gasket goes on, or the new gasket may leak.
What is the difference between a gasket and a seal?
A gasket sits between two flat mating surfaces, such as a cover and a case. A seal, such as a double lip seal, rides around a moving or turning part such as a shaft. Both keep fluids in.
