Engines & Components
About Engines & Components
Engine work on a snowmobile usually means one of three jobs: a top end rebuild after a seized or worn piston, routine ignition and starting parts, or a repair on a pull-start that has stopped catching. The parts for all of them are collected here, from piston kits and ring sets to gaskets, bearings, seals and recoil components.
The group is organized as Snowmobile Engine Components, and the listings inside show how to pick. Pistons are sold by bore diameter in millimeters, such as 66.50, 68.25 or 72.00, and some sizes step up for cylinders that have been rebored, so measure your cylinder and read the service manual first. A full top end set bundles the main wear parts for one job, while a complete gasket set suits a larger rebuild. Needle bearings and seals are matched by their dimensions, which are written into the title. Parts differ between two-stroke and four-stroke engines and between engine families, so make, model and year matter.
Brands in this group include Vertex, Hot Rods, EPI, Ultimax and NGK Spark Plugs. Pick your sled in the Ride Finder at the top of the page. A rebuilt engine also needs a healthy supply of air and spark, so see Exhaust, Electrical Components and Air Intake & Fuel Systems.
FAQs on snowmobile engine parts
How do I know which piston size my snowmobile needs?
Start with the standard bore listed in your manual, then measure the cylinder for wear. Pistons are listed by diameter in millimeters, and oversize versions exist for cylinders that have been rebored. Match the piston to the measured and finished cylinder, and check the listing's make and year.
What is a top end rebuild?
A top end rebuild replaces the parts at the top of the engine that wear fastest: the piston, rings, wrist pin bearing and gaskets, and sometimes the cylinder is refinished. The crankshaft and lower engine are left alone. It is often done after a seizure, a loss of compression or oil smoking.
Should I replace the rings when I replace a piston?
Yes. New rings should go on with a new piston and a fresh gasket set, because used rings have worn to the old cylinder and piston. Rings are listed by size, so make sure the ring set matches the piston bore you are fitting.
Do two-stroke and four-stroke snowmobile engines use the same parts?
No. Two-stroke and four-stroke engines are built differently, so their pistons, rings, gaskets and bearings are not interchangeable, and parts also vary between engine families. Match every part to your sled's make, model and year, and use the Ride Finder to narrow the list.
How do I find the right spark plug for my snowmobile?
The plug type, heat range and gap are in your owner's manual, and the plug's code is printed on its body. Use the type the manufacturer specifies, and replace plugs that are worn, fouled or have a damaged tip.
