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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COMETIC Gasket Set - 78 mm - Honda C3133-EST
COMETIC
$84.95Factory gaskets can't handle the cylinder pressures generated by high-output 4-stroke engines, whether naturally aspirated or boosted. The COMETIC C3133-EST gasket set uses multi-layered steel...09340920- SKU:
- 09340920
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- TYPE:
- TOP END
- BORE SIZE METRIC:
- 78.00 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
$84.95 -
COMETIC Gasket Set - 96 mm - Honda C3047-EST
COMETIC
$88.95When running high-output forced induction or naturally aspirated builds, your factory gasket set becomes a liability. The COMETIC C3047-EST Gasket Set uses advanced multi-layered steel construction...09340905- SKU:
- 09340905
- Availability:
- Ships Same Business Day
- Weight:
- 0.17 LBS
- TYPE:
- TOP END
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
- BORE SIZE METRIC:
- 96.00 MM
$88.95Qty in Cart: 0Quantity:Price:$88.95Subtotal: -
On Sale
ATHENA Cylinder Gasket Kit - Yamaha 070203/1
ATHENA
MSRP: $13.95Now: $13.00Was: $13.95When you've committed to a 70cc big bore conversion on your Yamaha, a compromised cylinder gasket is a silent performance killer—leaking compression, oil, and coolant before you even notice. The...09340639- SKU:
- 09340639
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- RIDING STYLE:
- STREET
- TYPE:
- TOP END
- PRODUCT NAME:
- GASKET KIT
- UNITS:
- KIT
MSRP: $13.95Now: $13.00Was: $13.95 -
On Sale
ATHENA Cylinder Gasket Kit - Yamaha 070103/1
ATHENA
MSRP: $14.95Now: $13.00Was: $14.95When you've upgraded to an Athena 70cc big bore kit, maintaining a reliable seal between your cylinder and head is critical to preserving compression and preventing coolant or oil leakage. This...09340638- SKU:
- 09340638
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- RIDING STYLE:
- STREET
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- TOP END
- UNITS:
- KIT
MSRP: $14.95Now: $13.00Was: $14.95 -
COMETIC Top End Gasket Kit C7181
COMETIC
$51.95A quality gasket kit is the foundation of a reliable top end—poor sealing leads to compression loss, oil leakage, and catastrophic engine failure. The COMETIC C7181 uses multi-layered steel...09340315- SKU:
- 09340315
- Availability:
- Ships Same Business Day
- Weight:
- 0.09 LBS
- THICKNESS IMPERIAL:
- 0,012'
- TYPE:
- TOP END
- BORE SIZE METRIC:
- 54.00 MM
- THICKNESS METRIC:
- 0.31 MM
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$51.95 -
WINDEROSA Top End Gasket Kit - SL/SLTX1100 610806
WINDEROSA
$67.05Top-end gasket failure leads to compression loss, oil leaks, and catastrophic engine damage—replacing them preventatively with a complete OEM-quality kit saves you thousands in rebuild costs. The...09340271- SKU:
- 09340271
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- TOP END
- UNITS:
- KIT
$67.05 -
On Sale
ATHENA Gasket - KLX/DRZ/KFX/LTZ400 P400510160002
ATHENA
MSRP: $133.95Now: $121.00Was: $133.95Stock gaskets wear down under sustained performance use, leading to coolant leaks and compromised sealing integrity that can damage your engine. The ATHENA Gasket Kit is engineered specifically for...09340194- SKU:
- 09340194
- Availability:
- Ships Same Business Day
- Weight:
- 0.18 LBS
- TYPE:
- TOP END
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- ATV
- BORE SIZE:
- 94,00 MM
- RIDING STYLE:
- STREET
- BORE SIZE METRIC:
- 94.00 MM
- DISPLACEMENT:
- 435 CC
- RIDING STYLE:
- OFF-ROAD
MSRP: $133.95Now: $121.00Was: $133.95Qty in Cart: 0Quantity:Price:MSRP: $133.95Now: $121.00Was: $133.95Subtotal: -
On Sale
ATHENA Cylinder Gasket Kit - KX125 P400250160001
ATHENA
MSRP: $53.95Now: $52.00Was: $53.95Maintain peak performance and reliability with the ATHENA Cylinder Gasket Kit, engineered to restore your KX125 to factory specifications or exceed them with premium materials. The nickel-carbide...09340190- SKU:
- 09340190
- Availability:
- Ships Same Business Day
- Weight:
- 0.06 LBS
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BORE SIZE:
- 54,00 MM
- BORE SIZE METRIC:
- 54.00 MM
- TYPE:
- TOP END
MSRP: $53.95Now: $52.00Was: $53.95 -
Cylinder Works Standard Bore High Compression Cylinder Kit for Polaris RZR 900 2015-2016 60004-K01HC
CYLINDER WORKS
$1,353.95If you're running a Polaris RZR 900 and want to restore original performance or eliminate the guesswork of piston-to-cylinder matching, this bolt-on kit delivers exactly what you need. The included...09310735- SKU:
- 09310735
- Availability:
- Ships Same Business Day
- Weight:
- 9.85 LBS
- UNITS:
- KIT
- BORE SIZE METRIC:
- 93.00 MM
- COMPRESSION RATIO IMPERIAL:
- 11.5:1
- CYLINDER DIAMETER:
- 93,00 MM
- ENGINE TYPE:
- 4-CYCLE
- PRODUCT NAME:
- CYLINDER KIT
- CYLINDER DIAMETER METRIC:
- 93.00 MM
- RIDING STYLE:
- UTV
- STYLE:
- STANDARD
$1,353.95 -
Cylinder Works Cylinder Kit Standard 40004-K02
CYLINDER WORKS
$704.95If you're running a two-stroke engine that's seen significant mileage, a worn cylinder directly kills performance—reducing compression, increasing blow-by, and forcing you to compensate with richer...09310502- SKU:
- 09310502
- Availability:
- Ships Same Business Day
- Weight:
- 3.30 LBS
- COMPRESSION RATIO IMPERIAL:
- 13.5:1
- CYLINDER DIAMETER METRIC:
- 77.00 MM
- DISPLACEMENT:
- 249 CC
- ENGINE TYPE:
- 4-CYCLE
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- STYLE:
- STANDARD
- CYLINDER DIAMETER:
- 77,00 MM
- PRODUCT NAME:
- CYLINDER KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$704.95 -
Cylinder Works Big Bore Cylinder Kit for Suzuki RM-Z250 2013-2018 41004-K02
CYLINDER WORKS
$799.95If you're running a 2013-2018 RM-Z250, a big bore cylinder kit is one of the most cost-effective ways to unlock measurable gains in displacement and power without a complete engine rebuild. The...09310501- SKU:
- 09310501
- Availability:
- Ships Same Business Day
- Weight:
- 3.20 LBS
- COMPRESSION RATIO IMPERIAL:
- 13.5:1
- ENGINE TYPE:
- 4-CYCLE
- PRODUCT NAME:
- CYLINDER KIT
- STYLE:
- BIG BORE
- CYLINDER DIAMETER METRIC:
- 80.00 MM
- RIDING STYLE:
- OFF-ROAD
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- CYLINDER DIAMETER:
- 80,00 MM
- DISPLACEMENT:
- 269 CC
- OVERBORE METRIC:
- +3.00 MM
- UNITS:
- KIT
$799.95 -
Cylinder Works Standard Bore Cylinder Kit KTM 65 SX 2009-2023 50005-K01
CYLINDER WORKS
$788.95When your KTM 65 SX starts showing signs of wear, a proper cylinder refresh is the most cost-effective way to restore lost compression and power. The Cylinder Works Standard Bore Kit eliminates...09310500- SKU:
- 09310500
- Availability:
- Ships Same Business Day
- Weight:
- 2.85 LBS
- COMPRESSION RATIO IMPERIAL:
- 2.09:1
- PRODUCT NAME:
- CYLINDER KIT
- CYLINDER DIAMETER:
- 45,00 MM
- CYLINDER DIAMETER METRIC:
- 45.00 MM
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- ENGINE TYPE:
- 2-CYCLE
- UNITS:
- KIT
- DISPLACEMENT:
- 65 CC
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- STANDARD
$788.95 -
Cylinder Works Standard Bore Cylinder Kit 2013-2015 KTM 350 SX-F 350 XC-F 50003-K01
CYLINDER WORKS
$867.95When your KTM 350 SX-F or XC-F's cylinder wears beyond acceptable limits, a quality replacement isn't optional—it's essential to maintaining peak compression, throttle response, and engine longevity...09310497- SKU:
- 09310497
- Availability:
- Ships Same Business Day
- Weight:
- 3.85 LBS
- COMPRESSION RATIO IMPERIAL:
- 13.6:1
- CYLINDER DIAMETER:
- 88,00 MM
- ENGINE TYPE:
- 4-CYCLE
- STYLE:
- STANDARD
- CYLINDER DIAMETER METRIC:
- 88.00 MM
- DISPLACEMENT:
- 350 CC
- RIDING STYLE:
- OFF-ROAD
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- PRODUCT NAME:
- CYLINDER KIT
- UNITS:
- KIT
$867.95Qty in Cart: 0Quantity:Price:$867.95Subtotal: -
Cylinder Works Big Bore Cylinder Kit for 2013-2015 KTM 350 SX-F 35003-K01
CYLINDER WORKS
$982.95If you're running a 2013-2015 KTM 350 SX-F, this big bore kit delivers measurable gains in displacement and power without requiring extensive machine work or re-plating. The bolt-on design means...09310495- SKU:
- 09310495
- Availability:
- Ships Same Business Day
- Weight:
- 3.70 LBS
- ENGINE TYPE:
- 4-CYCLE
- CYLINDER DIAMETER METRIC:
- 90.00 MM
- COMPRESSION RATIO IMPERIAL:
- 13.5:1
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- CYLINDER DIAMETER:
- 90,00 MM
- DISPLACEMENT:
- 365 CC
- OVERBORE METRIC:
- +2.00 MM
- PRODUCT NAME:
- CYLINDER KIT
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- BIG BORE
- UNITS:
- KIT
$982.95Qty in Cart: 0Quantity:Price:$982.95Subtotal: -
Cylinder Works Yamaha YZ 450 F 2010-2013 High Compression Cylinder Kit 21005-K01
CYLINDER WORKS
$901.95Stock YZ 450F cylinders sacrifice durability and peak performance for cost savings. The Cylinder Works High Compression Kit restores the power and reliability your engine demands, delivering...09310354- SKU:
- 09310354
- Availability:
- Ships Same Business Day
- Weight:
- 4.45 LBS
- CYLINDER DIAMETER METRIC:
- 99.00 MM
- RIDING STYLE:
- OFF-ROAD
- DISPLACEMENT:
- 468 CC
- STYLE:
- HIGH COMPRESSION
- COMPRESSION RATIO IMPERIAL:
- 12.5:1
- CYLINDER DIAMETER:
- 99,00 MM
- ENGINE TYPE:
- 4-CYCLE
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- PRODUCT NAME:
- CYLINDER KIT
- UNITS:
- KIT
$901.95Qty in Cart: 0Quantity:Price:$901.95Subtotal: -
Cylinder Works Standard Bore Cylinder Kit 77mm 13.4:1 Compression Suzuki RM-Z250 2007-2009 40003-K01
CYLINDER WORKS
$704.95If you're running a 2007-2009 RM-Z250 and want genuine performance gains without the headache of machine work, this Cylinder Works kit delivers a straightforward path to increased displacement and...09310352- SKU:
- 09310352
- Availability:
- Ships Same Business Day
- Weight:
- 3.20 LBS
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- CYLINDER DIAMETER:
- 77,00 MM
- DISPLACEMENT:
- 249 CC
- ENGINE TYPE:
- 4-CYCLE
- PRODUCT NAME:
- CYLINDER KIT
- CYLINDER DIAMETER METRIC:
- 77.00 MM
- STYLE:
- STANDARD
- COMPRESSION RATIO IMPERIAL:
- 13.4:1
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
$704.95Qty in Cart: 0Quantity:Price:$704.95Subtotal: -
Cylinder Works Standard Bore Cylinder Kit 2010-2013 Yamaha YZ450F 20005-K01
CYLINDER WORKS
$804.95If you're running a 2010-2013 YZ450F, a worn or damaged cylinder directly impacts combustion efficiency, power delivery, and engine longevity. The Cylinder Works Standard Bore Kit restores your...09310345- SKU:
- 09310345
- Availability:
- Ships Same Business Day
- Weight:
- 4.58 LBS
- CYLINDER DIAMETER:
- 97,00 MM
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- STYLE:
- STANDARD
- COMPRESSION RATIO IMPERIAL:
- 12.5:1
- CYLINDER DIAMETER METRIC:
- 97.00 MM
- ENGINE TYPE:
- 4-CYCLE
- DISPLACEMENT:
- 449 CC
- PRODUCT NAME:
- CYLINDER KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$804.95 -
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
