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!
- Product
- Qty in Cart
- Quantity
- Price
- Subtotal
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Cylinder Works Kawasaki KX250F 2010 Standard Bore Cylinder Kit 77mm 13.2:1 30005-K01
CYLINDER WORKS
$679.95Factory cylinder wear limits piston-to-wall clearance and reduces combustion efficiency—a complete cylinder kit restores your KX250F's compression, throttle response, and ring seal integrity. The...09310341- SKU:
- 09310341
- Availability:
- Ships Same Business Day
- Weight:
- 3.30 LBS
- COMPRESSION RATIO IMPERIAL:
- 13.2:1
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- CYLINDER DIAMETER:
- 77,00 MM
- DISPLACEMENT:
- 249 CC
- ENGINE TYPE:
- 4-CYCLE
- PRODUCT NAME:
- CYLINDER
- CYLINDER DIAMETER METRIC:
- 77.00 MM
- STYLE:
- STANDARD
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
$679.95 -
Cylinder Works Honda CRF 250R 2010-2017 Big Bore Cylinder Kit 270cc 11007-K01
CYLINDER WORKS
$758.95Stock displacement limits your Honda CRF 250R's potential—this big bore kit unlocks an additional 20cc of swept volume, delivering measurable gains in mid-range torque and top-end power without...09310340- SKU:
- 09310340
- Availability:
- Ships Same Business Day
- Weight:
- 3.68 LBS
- COMPRESSION RATIO IMPERIAL:
- 13.2:1
- CYLINDER DIAMETER METRIC:
- 80.00 MM
- RIDING STYLE:
- OFF-ROAD
- DISPLACEMENT:
- 270 CC
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- CYLINDER DIAMETER:
- 80,00 MM
- PRODUCT NAME:
- CYLINDER KIT
- STYLE:
- BIG BORE
- UNITS:
- KIT
- ENGINE TYPE:
- 4-CYCLE
- OVERBORE METRIC:
- +3.20 MM
$758.95Qty in Cart: 0Quantity:Price:$758.95Subtotal: -
Cylinder Works Standard Bore Cylinder Kit Honda CRF250R 2010-2013 10007-K01
CYLINDER WORKS
$597.95When you're pushing a CRF250R to its limits, factory tolerances become a ceiling, not a target. The Cylinder Works Standard Bore Kit delivers a bolt-on refresh that restores compression, improves...09310338- SKU:
- 09310338
- Availability:
- Ships Same Business Day
- Weight:
- 3.55 LBS
- DISPLACEMENT:
- 249 CC
- ENGINE TYPE:
- 4-CYCLE
- PRODUCT NAME:
- CYLINDER KIT
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- CYLINDER DIAMETER:
- 76,80 MM
- UNITS:
- KIT
- CYLINDER DIAMETER METRIC:
- 76.80 MM
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- STANDARD
- COMPRESSION RATIO IMPERIAL:
- 13.2:1
$597.95 -
On Sale
ATHENA Cylinder Kit - KX250F P400250100013
ATHENA
MSRP: $1,105.30Now: $995.00Was: $1,105.30A worn or damaged cylinder directly compromises your KX250F's power delivery, throttle response, and overall reliability on the track. The ATHENA Cylinder Kit restores factory performance while...09310308- SKU:
- 09310308
- Availability:
- Ships Same Business Day
- Weight:
- 3.03 LBS
- BORE SIZE METRIC:
- 83.00 MM
- DISPLACEMENT:
- 290 CC
- ENGINE TYPE:
- 4-STROKE
- RIDING STYLE:
- OFF-ROAD
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- MATERIAL:
- ALUMINUM
- PRODUCT NAME:
- CYLINDER KIT
- STYLE:
- BIG BORE
- UNITS:
- KIT
MSRP: $1,105.30Now: $995.00Was: $1,105.30 -
Cylinder Works Standard Bore Cylinder Kit for 2002-2008 Honda CRF450R 10002-K01
CYLINDER WORKS
$651.95The Honda CRF450R demands reliable power delivery, especially if you're logging serious hours at the track or trail. This Cylinder Works kit delivers a complete bolt-on solution with matched Vertex...09310272- SKU:
- 09310272
- Availability:
- Ships Same Business Day
- Weight:
- 4.51 LBS
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- CYLINDER DIAMETER:
- 96,00 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- COMPRESSION RATIO IMPERIAL:
- 12.1:1
- DISPLACEMENT:
- 449 CC
- ENGINE TYPE:
- 4-CYCLE
- PRODUCT NAME:
- CYLINDER KIT
- CYLINDER DIAMETER METRIC:
- 96.00 MM
- STYLE:
- STANDARD
$651.95 -
Cylinder Works Standard Bore Cylinder Kit Honda CRF250R 2008-2009 10001-K02
CYLINDER WORKS
$609.95The Honda CRF250R demands reliable power delivery, and a worn cylinder limits both performance and engine longevity. This Cylinder Works Standard Bore Kit restores your engine to peak efficiency with...09310271- SKU:
- 09310271
- Availability:
- Ships Same Business Day
- Weight:
- 3.55 LBS
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- STYLE:
- STANDARD
- COMPRESSION RATIO IMPERIAL:
- 13.0:1
- CYLINDER DIAMETER:
- 78,00 MM
- DISPLACEMENT:
- 249 CC
- ENGINE TYPE:
- 4-CYCLE
- PRODUCT NAME:
- CYLINDER KIT
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- CYLINDER DIAMETER METRIC:
- 78.00 MM
$609.95 -
Cylinder Works Standard Bore Cylinder Kit Honda CRF450R 2017-2018 10001-K01
CYLINDER WORKS
$597.95Stock cylinder wear limits your CRF450R's potential, whether you're chasing track times or extending engine life on your rebuild. The Cylinder Works Standard Bore Kit delivers a direct bolt-on...09310270- SKU:
- 09310270
- Availability:
- Ships Same Business Day
- Weight:
- 4.32 LBS
- COMPRESSION RATIO IMPERIAL:
- 12.9:1
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- CYLINDER DIAMETER METRIC:
- 78.00 MM
- CYLINDER DIAMETER:
- 78,00 MM
- DISPLACEMENT:
- 249 CC
- ENGINE TYPE:
- 4-CYCLE
- PRODUCT NAME:
- CYLINDER KIT
- STYLE:
- STANDARD
$597.95 -
Cylinder Works Cylinder Kit Standard 66mm Bore 11.7:1 Compression Honda CRF150R 2007-2009 10004-K01
CYLINDER WORKS
$550.95If you're running a CRF150R and want measurable power gains without the downtime of traditional re-plating, this complete cylinder kit delivers bolt-on simplicity and proven durability. The matched...09310269- SKU:
- 09310269
- Availability:
- Ships Same Business Day
- Weight:
- 2.80 LBS
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- CYLINDER DIAMETER METRIC:
- 66.00 MM
- STYLE:
- STANDARD
- CYLINDER DIAMETER:
- 66,00 MM
- DISPLACEMENT:
- 149 CC
- ENGINE TYPE:
- 4-CYCLE
- COMPRESSION RATIO IMPERIAL:
- 11.7:1
- PRODUCT NAME:
- CYLINDER KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$550.95 -
On Sale
ATHENA Cylinder Kit - YZ125 - 58mm P400485100029
ATHENA
MSRP: $1,131.95Now: $1,102.00Was: $1,131.95The ATHENA Cylinder Kit for YZ125 delivers measurable performance gains through precision engineering and superior materials. If you're running stock components, you're leaving horsepower on the...09310258- SKU:
- 09310258
- Availability:
- Ships Same Business Day
- Weight:
- 5.43 LBS
- BORE SIZE METRIC:
- 58.00 MM
- MATERIAL:
- ALUMINUM
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- ENGINE TYPE:
- 2-STROKE
- DISPLACEMENT:
- 144 CC
- PRODUCT NAME:
- CYLINDER KIT
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- BIG BORE
- UNITS:
- KIT
MSRP: $1,131.95Now: $1,102.00Was: $1,131.95 -
On Sale
ATHENA Cylinder Kit - WR250R/X - 83mm P400485100032
ATHENA
MSRP: $1,352.95Now: $1,218.00Was: $1,352.95If you're running a WR250R/X and want to unlock genuine displacement gains with measurable power increases, the ATHENA Cylinder Kit delivers the reliability and precision engineering that separates...09310252- SKU:
- 09310252
- Availability:
- Ships Same Business Day
- Weight:
- 4.29 LBS
- PRODUCT NAME:
- CYLINDER KIT
- STYLE:
- BIG BORE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BORE SIZE METRIC:
- 83.00 MM
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- DISPLACEMENT:
- 290 CC
- ENGINE TYPE:
- 4-STROKE
- MATERIAL:
- ALUMINUM
MSRP: $1,352.95Now: $1,218.00Was: $1,352.95Qty in Cart: 0Quantity:Price:MSRP: $1,352.95Now: $1,218.00Was: $1,352.95Subtotal: -
On Sale
ATHENA Cylinder Kit - SX65 - 50mm P400270100002
ATHENA
MSRP: $872.95Now: $786.00Was: $872.95The ATHENA Cylinder Kit for SX65 delivers the displacement and thermal management your 50mm bore demands. With a nickel-carbide coated aluminum cylinder and forged piston engineered for durability,...09310245- SKU:
- 09310245
- Availability:
- Ships Same Business Day
- Weight:
- 3.28 LBS
- DISPLACEMENT:
- 80 CC
- MATERIAL:
- ALUMINUM
- BORE SIZE METRIC:
- 50.00 MM
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- CYLINDER KIT
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- BIG BORE
- UNITS:
- KIT
MSRP: $872.95Now: $786.00Was: $872.95Qty in Cart: 0Quantity:Price:MSRP: $872.95Now: $786.00Was: $872.95Subtotal: -
Cylinder Works Big Bore Kit Yamaha YZ450F 2006-2009 WR450F 2007-2015 21003-K01
CYLINDER WORKS
$873.95If you're running a YZ450F or WR450F and want measurable gains in displacement and power output, a big bore kit is the most efficient path forward. The Cylinder Works Big Bore Kit delivers bolt-on...09310174- SKU:
- 09310174
- Availability:
- Ships Same Business Day
- Weight:
- 4.04 LBS
- ENGINE TYPE:
- 4-CYCLE
- PRODUCT NAME:
- CYLINDER KIT
- STYLE:
- BIG BORE
- DISPLACEMENT:
- 478 CC
- COMPRESSION RATIO IMPERIAL:
- 12.5:1
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- CYLINDER DIAMETER:
- 98,00 MM
- CYLINDER DIAMETER METRIC:
- 98.00 MM
- OVERBORE METRIC:
- +3.00 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$873.95Qty in Cart: 0Quantity:Price:$873.95Subtotal: -
Cylinder Works Big Bore Cylinder Kit for Honda CRF250R 2004-2009 2012-2013 CRF250X 2004-2017 11001-K01
CYLINDER WORKS
$752.95If you're running a CRF250R or CRF250X and want measurable gains in displacement and power without a complete engine overhaul, the Cylinder Works Big Bore Kit delivers exactly that. This bolt-on...09310118- SKU:
- 09310118
- Availability:
- Ships Same Business Day
- Weight:
- 3.03 LBS
- CYLINDER DIAMETER METRIC:
- 81.00 MM
- RIDING STYLE:
- OFF-ROAD
- ENGINE TYPE:
- 4-CYCLE
- COMPRESSION RATIO IMPERIAL:
- 13.0:1
- CYLINDER DIAMETER:
- 81,00 MM
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- DISPLACEMENT:
- 269 CC
- OVERBORE METRIC:
- +3.00 MM
- PRODUCT NAME:
- CYLINDER KIT
- STYLE:
- BIG BORE
- UNITS:
- KIT
$752.95 -
On Sale
ATHENA Cylinder Kit - RMZ450 - 100mm P400510100006
ATHENA
MSRP: $1,156.95Now: $1,041.00Was: $1,156.95The ATHENA Cylinder Kit delivers measurable gains in displacement and compression for the RMZ450, translating directly to increased horsepower and throttle response. The nickel-carbide coated...09310114- SKU:
- 09310114
- Availability:
- Ships Same Business Day
- Weight:
- 3.73 LBS
- PRODUCT NAME:
- CYLINDER KIT
- STYLE:
- BIG BORE
- DISPLACEMENT:
- 490 CC
- ENGINE TYPE:
- 4-STROKE
- MATERIAL:
- ALUMINUM
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- UNITS:
- KIT
- BORE SIZE METRIC:
- 100.00 MM
- RIDING STYLE:
- OFF-ROAD
MSRP: $1,156.95Now: $1,041.00Was: $1,156.95 -
On Sale
ATHENA Cylinder Kit - KX125 - 58mm P400250100011
ATHENA
MSRP: $1,201.95Now: $1,082.00Was: $1,201.95The ATHENA Cylinder Kit delivers the displacement and reliability your KX125 demands when stock limits won't cut it. With a 58mm bore, optimized water jacket design, and factory-grade coatings,...09310109- SKU:
- 09310109
- Availability:
- Ships Same Business Day
- Weight:
- 5.62 LBS
- BORE SIZE METRIC:
- 58.00 MM
- MATERIAL:
- ALUMINUM
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- ENGINE TYPE:
- 2-STROKE
- RIDING STYLE:
- OFF-ROAD
- DISPLACEMENT:
- 144 CC
- PRODUCT NAME:
- CYLINDER KIT
- STYLE:
- BIG BORE
- UNITS:
- KIT
MSRP: $1,201.95Now: $1,082.00Was: $1,201.95 -
On Sale
ATHENA Cylinder Kit - KX65 - 50mm P400250100007
ATHENA
MSRP: $863.95Now: $840.00Was: $863.95If you're pushing your KX65 to its limits, a worn or compromised cylinder is a bottleneck you can't afford. The ATHENA Cylinder Kit delivers measurable gains in compression consistency and heat...09310107- SKU:
- 09310107
- Availability:
- Ships Same Business Day
- Weight:
- 3.31 LBS
- PRODUCT NAME:
- CYLINDER KIT
- STYLE:
- BIG BORE
- DISPLACEMENT:
- 80 CC
- BORE SIZE METRIC:
- 50.00 MM
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- ENGINE TYPE:
- 2-STROKE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- MATERIAL:
- ALUMINUM
MSRP: $863.95Now: $840.00Was: $863.95 -
On Sale
ATHENA Cylinder Kit - YZ125 - 54mm P400485100017
ATHENA
MSRP: $1,027.95Now: $1,000.00Was: $1,027.95The ATHENA Cylinder Kit delivers the displacement and reliability your YZ125 needs to stay competitive on the track. With a larger 54mm bore and premium coatings engineered for durability, this kit...09310095- SKU:
- 09310095
- Availability:
- Ships Same Business Day
- Weight:
- 5.61 LBS
- DISPLACEMENT:
- 125 CC
- PRODUCT NAME:
- CYLINDER KIT
- MATERIAL:
- ALUMINUM
- BORE SIZE METRIC:
- 54.00 MM
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- ENGINE TYPE:
- 2-STROKE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- STYLE:
- STOCK BORE
MSRP: $1,027.95Now: $1,000.00Was: $1,027.95 -
On Sale
ATHENA Cylinder Kit - Yamaha 070200
ATHENA
MSRP: $243.95Now: $237.00Was: $243.95Restore your Yamaha's peak performance with a complete cylinder kit engineered for reliability and longevity. The ATHENA 070200 combines a reinforced aluminum cylinder with advanced thermal...09310077- SKU:
- 09310077
- Availability:
- Ships Same Business Day
- Weight:
- 2.70 LBS
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- ENGINE TYPE:
- 2-STROKE
- UNITS:
- KIT
- DISPLACEMENT:
- 70 CC
- PRODUCT NAME:
- CYLINDER KIT
- RIDING STYLE:
- STREET
- STYLE:
- BIG BORE
- BORE SIZE METRIC:
- 47.66 MM
- MATERIAL:
- ALUMINUM
MSRP: $243.95Now: $237.00Was: $243.95 -
On Sale
ATHENA Cylinder Kit - Yamaha/Malaguti 070100
ATHENA
MSRP: $262.95Now: $237.00Was: $262.95When you're ready to unlock serious performance gains on your Yamaha or Malaguti 070, a quality cylinder kit is non-negotiable. The ATHENA Cylinder Kit delivers the displacement and durability you...09310076- SKU:
- 09310076
- Availability:
- Ships Same Business Day
- Weight:
- 2.80 LBS
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- UNITS:
- KIT
- DISPLACEMENT:
- 70 CC
- PRODUCT NAME:
- CYLINDER KIT
- RIDING STYLE:
- STREET
- STYLE:
- BIG BORE
- BORE SIZE METRIC:
- 47.66 MM
- ENGINE TYPE:
- 2-STROKE
- MATERIAL:
- ALUMINUM
MSRP: $262.95Now: $237.00Was: $262.95Qty in Cart: 0Quantity:Price:MSRP: $262.95Now: $237.00Was: $262.95Subtotal: -
On Sale
ATHENA Cylinder Kit - KLX/DRZ/KFX/LTZ400 P400510100002
ATHENA
MSRP: $1,117.95Now: $1,006.00Was: $1,117.95Stock cylinder limitations can compromise peak horsepower and throttle response on your KLX, DRZ, KFX, or LTZ400. The ATHENA Cylinder Kit delivers measurable gains through advanced materials and...09310016- SKU:
- 09310016
- Availability:
- Ships Same Business Day
- Weight:
- 4.96 LBS
- DISPLACEMENT:
- 435 CC
- MATERIAL:
- ALUMINUM
- BORE SIZE METRIC:
- 94.00 MM
- ENGINE TYPE:
- 4-STROKE
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- RIDING STYLE:
- STREET
- PRODUCT NAME:
- CYLINDER KIT
- STYLE:
- BIG BORE
- UNITS:
- KIT
MSRP: $1,117.95Now: $1,006.00Was: $1,117.95
