Dirt Bike Crank Main Bearings & Seal Kits – Complete Bottom-End Rebuild Essentials
Protect the heart of your engine with our crank main bearings and seal kits — everything you need to properly rebuild your bottom end and stop costly oil leaks, crank play, and premature engine failur... show more
Dirt Bike Crank Main Bearings & Seal Kits – Complete Bottom-End Rebuild Essentials
Protect the heart of your engine with our crank main bearings and seal kits — everything you need to properly rebuild your bottom end and stop costly oil leaks, crank play, and premature engine failure. When your crankshaft starts to feel notchy or your cases start weeping oil, replacing worn bearings and seals together is the only reliable fix.
Why Riders Choose Our Main Bearings & Seal Kits
- Complete Kit, No Guesswork – Includes both left and right main bearings plus matching crank seals in one box, so nothing gets missed on a rebuild
- Premium Bearing Brands – Sourced from trusted manufacturers (SKF, Koyo, and equivalent OEM-spec suppliers) for smooth rotation and long service life
- Fuel & Oil-Resistant Seals – High-quality nitrile or Viton seal material holds up against modern fuels, oils, and heat cycling without hardening or leaking
- Precision Tolerances – Bearings and seals machined to factory specification for correct crank clearance and case sealing
Wide Model Range – Available for Honda CRF, Yamaha YZ/YZF, KTM SX/SX-F/EXC, Kawasaki KX/KX-F, and Suzuki RM/RM-Z
Why Bearings and Seals Should Be Replaced Together
Worn main bearings almost always go hand in hand with tired crank seals — once the bearing develops play, it accelerates seal wear, and a failing seal lets air and contaminants past, which accelerates bearing wear in return. Replacing them as a matched pair during any bottom-end rebuild avoids a repeat teardown a few rides later, and protects against transmission fluid contamination, air leaks affecting carburetion, and crankshaft damage from excessive play.
Perfect For
- Full bottom-end and crankshaft rebuilds
- Bikes showing notchy crank rotation or excessive play
- Engines with visible case oil weeping or air leaks
- Pre-season engine servicing and high-hours rebuilds
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