Cylinder Bolts
About Cylinder Bolts
Cylinder studs and head bolts clamp the cylinder and cylinder head down onto the crankcase and hold the head gasket tight. They stretch, corrode or strip with age and repeated use, and a loose or damaged one can cause a head gasket leak. Riders replace them when the cylinder is off, when a thread is damaged, or when they fit stronger fasteners for a built engine.
Most listings are sets for Harley-Davidson, such as cylinder stud kits for Evolution, Twin Cam and Sportster engines and 12-point head bolt sets, plus engine fastener kits for newer KTM, Gas Gas, Husqvarna, Yamaha and Kawasaki dirt bikes. A stud is threaded at both ends and the cylinder and head slide over it, while a bolt threads into the case. The engine and years decide which one you need, so match the title. Tighten the fasteners to the figures and in the order your service manual gives, and check whether it permits reusing them. Fit a new head gasket whenever you take the head off.
Brands in this category include Bolt, Colony, Jims, Feuling Parts and Kibblewhite. Related categories are Complete Cylinders, Cylinder Heads and Gaskets, Seals & Kits. The full group is Engines & Engine Parts. Pick your machine in the Ride Finder at the top of the page.
FAQs on cylinder studs and head bolts
What is the difference between a cylinder stud and a head bolt?
A stud is a rod threaded at both ends. It screws into the crankcase and the cylinder and head slide over it, then nuts hold them down. A head bolt has a head and threads into the case. Which one your engine uses is set by its design.
Can I reuse cylinder studs and head bolts?
It depends on the engine and the fastener. Check your service manual, because some fasteners must be replaced after one use, and any that are stretched, rusty or have damaged threads should be replaced. When in doubt, fit new ones.
Do I need new studs when I replace a cylinder?
Not always. Inspect the old ones for bent shanks, damaged threads and corrosion, and replace them if there is any doubt. If you are changing the cylinder for a different type, the kit may call for different studs, so check the instructions.
How do I tighten cylinder head bolts correctly?
Use a torque wrench, follow the tightening order and the stages your manual gives, and make sure the threads are clean and, where the manual says so, lightly lubricated. Even tightening keeps the head flat against the gasket and avoids leaks.
What is an engine fastener kit?
It is a set of bolts and screws for a specific engine, sold as a group so you can replace damaged or lost fasteners at once. The kits in this category are made for particular dirt bike models and years, so check that yours is listed.
