Dirt Bike Engine
Dirt Bike Engine Parts at JJ Motorsports
Discover a full range of dirt bike engine components for rebuilding or upgrading your performance from JJ Motorsports. From crankshafts to cylinder heads and piston kits, these precision-engineered components ensure reliable performance. For additional upgrades, check out our full selection of off-road dirt bike parts to keep your engine running at peak efficiency on the track or trails.
Shop trusted brands like Wiseco for forged piston kits and K&N for high-flow oil filters. Explore related categories such as Dirt Bike Air and Fuel for intake upgrades or Dirt Bike Exhaust for complete systems.
Browse our in-stock inventory below with same-day shipping and expert support. Questions? Contact us for fitment advice!
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- Quantity
- Price
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On Sale
Wossner Crankshaft Assembly for Honda CRF250R 2010-2017 CS4001
WOSSNER
MSRP: $404.00Now: $383.80Was: $404.00The crankshaft is the heart of your engine—when it wears or fails, your CRF250R's performance suffers immediately. This Wossner assembly restores full power delivery and reliability with OEM-quality...09210881- SKU:
- 09210881
- Availability:
- Ships Same Business Day
- Weight:
- 8.49 LBS
MSRP: $404.00Now: $383.80Was: $404.00 -
On Sale
Wossner Crankshaft Assembly Kawasaki KX85 2006-2021 KX100 2006-2021 CS2005
WOSSNER
MSRP: $282.00Now: $267.90Was: $282.00A worn or damaged crankshaft assembly directly compromises your KX85 or KX100's reliability and power delivery. This Wossner complete assembly restores your engine to OEM-spec performance with...09210907- SKU:
- 09210907
- Availability:
- Ships Same Business Day
- Weight:
- 4.14 LBS
MSRP: $282.00Now: $267.90Was: $282.00 -
On Sale
Wossner Crankshaft Assembly Yamaha YZ85 2002-2018 CS2008
WOSSNER
MSRP: $262.00Now: $248.90Was: $262.00A worn or damaged crankshaft assembly directly impacts engine reliability, throttle response, and overall power delivery on your YZ85. This complete Wossner assembly restores your engine to factory...09210908- SKU:
- 09210908
- Availability:
- Ships Same Business Day
- Weight:
- 4.11 LBS
MSRP: $262.00Now: $248.90Was: $262.00Qty in Cart: 0Quantity:Price:MSRP: $262.00Now: $248.90Was: $262.00Subtotal: -
On Sale
Wossner Crankshaft Assembly Honda CR125R 1990-2007 CS2009
WOSSNER
MSRP: $342.00Now: $324.90Was: $342.00The crankshaft is the heart of your engine—when it fails or wears, your CR125R loses power, reliability, and precision. This Wossner assembly restores full performance with a CNC-precision...09210909- SKU:
- 09210909
- Availability:
- Ships Same Business Day
- Weight:
- 6.06 LBS
MSRP: $342.00Now: $324.90Was: $342.00 -
On Sale
Wossner Crankshaft Assembly Yamaha YZ125 2005-2021 YZ125X 2020-2022 CS2018
WOSSNER
MSRP: $342.00Now: $324.90Was: $342.00A worn or damaged crankshaft directly compromises engine performance, reliability, and longevity. This Wossner assembly restores factory specifications and efficiency without the need for individual...09210911- SKU:
- 09210911
- Availability:
- Ships Same Business Day
- Weight:
- 6.05 LBS
MSRP: $342.00Now: $324.90Was: $342.00Qty in Cart: 0Quantity:Price:MSRP: $342.00Now: $324.90Was: $342.00Subtotal: -
On Sale
Wossner Crankshaft Assembly Yamaha YZ250 2003-2024 CS2028
WOSSNER
MSRP: $482.95Now: $458.80Was: $482.95A worn or damaged crankshaft directly compromises your YZ250's power delivery, throttle response, and engine reliability. The Wossner CS2028 restores full performance potential with...09210912- SKU:
- 09210912
- Availability:
- Ships Same Business Day
- Weight:
- 9.00 LBS
MSRP: $482.95Now: $458.80Was: $482.95 -
On Sale
Wossner Crankshaft Assembly Gas Gas MC 65 2021-2022 CS2055
WOSSNER
MSRP: $282.00Now: $267.90Was: $282.00A worn or damaged crankshaft directly compromises engine efficiency, throttle response, and overall reliability—especially in high-demand 2-stroke applications. The Wossner CS2055 restores your Gas...09210913- SKU:
- 09210913
- Availability:
- Ships Same Business Day
- Weight:
- 3.97 LBS
MSRP: $282.00Now: $267.90Was: $282.00Qty in Cart: 0Quantity:Price:MSRP: $282.00Now: $267.90Was: $282.00Subtotal: -
On Sale
Wossner Crankshaft Assembly KTM 85 SX 2018-2025 CS2065-2
WOSSNER
MSRP: $382.95Now: $363.80Was: $382.95Your KTM 85 SX's crankshaft is the heartbeat of engine performance—worn bearings and play in the connecting rod rob you of power, throttle response, and reliability when you need it most. The Wossner...09210915- SKU:
- 09210915
- Availability:
- Ships Same Business Day
- Weight:
- 4.38 LBS
MSRP: $382.95Now: $363.80Was: $382.95 -
On Sale
Wossner Crankshaft Assembly Yamaha YZ65 2018-2025 CS2071
WOSSNER
MSRP: $262.00Now: $248.90Was: $262.00A worn or damaged crankshaft directly compromises engine reliability and performance—especially critical on a high-revving YZ65 where precise reciprocating motion is essential. The Wossner CS2071...09210916- SKU:
- 09210916
- Availability:
- Ships Same Business Day
- Weight:
- 3.61 LBS
MSRP: $262.00Now: $248.90Was: $262.00 -
On Sale
Wossner Crankshaft Assembly Yamaha YZ250F 2014-2021 CS4072
WOSSNER
MSRP: $404.00Now: $383.80Was: $404.00The CS4072 crankshaft assembly is a precision-engineered replacement that restores your YZ250F's bottom-end reliability and maintains factory performance specifications. Whether you're rebuilding...09210921- SKU:
- 09210921
- Availability:
- Ships Same Business Day
- Weight:
- 7.00 LBS
MSRP: $404.00Now: $383.80Was: $404.00 -
On Sale
VINTCO Top End Piston Kit KTH01-00
VINTCO
MSRP: $183.95Now: $171.07Was: $183.95A worn top end compromises both power output and engine reliability—this kit gives you everything needed for a complete rebuild in one box. Whether you're restoring a tired engine or upgrading after...09106407- SKU:
- 09106407
- Availability:
- Ships Same Business Day
- Weight:
- 1.01 LBS
MSRP: $183.95Now: $171.07Was: $183.95 -
On Sale
VINTCO Top End Piston Kit KTH01-0.5
VINTCO
MSRP: $198.85Now: $184.93Was: $198.85A worn top end compromises both power delivery and engine longevity—this complete piston kit restores OEM specifications while delivering the reliability demanded by serious builders and racers. The...09106408- SKU:
- 09106408
- Availability:
- Ships Same Business Day
- Weight:
- 1.06 LBS
MSRP: $198.85Now: $184.93Was: $198.85Qty in Cart: 0Quantity:Price:MSRP: $198.85Now: $184.93Was: $198.85Subtotal: -
On Sale
VINTCO Top End Piston Kit KTH01-1.0
VINTCO
MSRP: $198.85Now: $184.93Was: $198.85A complete top-end rebuild requires precision-engineered components that work in concert—and this kit delivers all the critical parts in one package. Whether you're restoring lost compression,...09106409- SKU:
- 09106409
- Availability:
- Ships Same Business Day
- Weight:
- 1.06 LBS
MSRP: $198.85Now: $184.93Was: $198.85 -
On Sale
VINTCO Top End Piston Kit KTH01-1.5
VINTCO
MSRP: $198.85Now: $184.93Was: $198.85A top-end rebuild demands precision components and complete gasket coverage—this kit eliminates sourcing parts piecemeal and ensures your engine seals properly at every critical junction. Whether...09106410- SKU:
- 09106410
- Availability:
- Ships Same Business Day
- Weight:
- 1.01 LBS
MSRP: $198.85Now: $184.93Was: $198.85 -
On Sale
VINTCO Top End Piston Kit KTH02-00
VINTCO
MSRP: $188.85Now: $175.63Was: $188.85A complete top-end rebuild requires precision components that work in harmony—and this kit delivers all the critical parts in one box. Whether you're refreshing a worn engine or building a...09106411- SKU:
- 09106411
- Availability:
- Ships Same Business Day
- Weight:
- 0.92 LBS
MSRP: $188.85Now: $175.63Was: $188.85 -
On Sale
VINTCO Top End Piston Kit KTH02-0.5
VINTCO
MSRP: $188.85Now: $175.63Was: $188.85A worn or damaged top end is a reliability killer—and rebuilding with OEM-equivalent components ensures your engine performs at its peak without compromise. The VINTCO KTH02-0.5 gives you everything...09106412- SKU:
- 09106412
- Availability:
- Ships Same Business Day
- Weight:
- 1.01 LBS
MSRP: $188.85Now: $175.63Was: $188.85 -
On Sale
VINTCO Top End Piston Kit KTH02-1.0
VINTCO
MSRP: $188.85Now: $175.63Was: $188.85A top-end rebuild demands precision components that restore compression, sealing, and reliability. The VINTCO KTH02-1.0 delivers a complete piston assembly with matched rings, bearings, and...09106413- SKU:
- 09106413
- Availability:
- Ships Same Business Day
- Weight:
- 1.01 LBS
MSRP: $188.85Now: $175.63Was: $188.85 -
On Sale
VINTCO Top End Piston Kit KTH02-1.5
VINTCO
MSRP: $185.95Now: $172.93Was: $185.95A worn or damaged top end is the silent killer of engine performance—excessive blow-by, lost compression, and oil consumption are your first warning signs. This VINTCO Top End Piston Kit delivers...09106414- SKU:
- 09106414
- Availability:
- Ships Same Business Day
- Weight:
- 0.91 LBS
MSRP: $185.95Now: $172.93Was: $185.95Qty in Cart: 0Quantity:Price:MSRP: $185.95Now: $172.93Was: $185.95Subtotal: -
On Sale
VINTCO Top End Piston Kit KTH03-00
VINTCO
MSRP: $195.85Now: $182.14Was: $195.85A worn or damaged top end compromises combustion efficiency and reliability—this comprehensive piston kit delivers everything needed for a complete, properly-sealed rebuild. Whether you're recovering...09106415- SKU:
- 09106415
- Availability:
- Ships Same Business Day
- Weight:
- 1.31 LBS
MSRP: $195.85Now: $182.14Was: $195.85Qty in Cart: 0Quantity:Price:MSRP: $195.85Now: $182.14Was: $195.85Subtotal: -
On Sale
VINTCO Top End Piston Kit KTH03-0.5
VINTCO
MSRP: $195.85Now: $182.14Was: $195.85A worn or damaged top end doesn't just cost you performance—it costs you reliability on the track or trail. The VINTCO Top End Piston Kit KTH03-0.5 gives you a complete solution with OEM-quality...09106416- SKU:
- 09106416
- Availability:
- Ships Same Business Day
- Weight:
- 1.01 LBS
MSRP: $195.85Now: $182.14Was: $195.85
