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
-
On Sale
ATHENA Top End Gasket Kit - Suzuki P400510600098
ATHENA
MSRP: $73.95Now: $67.00Was: $73.95Engine freshening before race season requires precision-engineered gaskets that can handle varying fuel grades and compression ratios without compromise. The ATHENA Top End Gasket Kit gives you the flexibility to run either pump gas with stock...09342536- SKU:
- 09342536
- Availability:
- Ships Same Business Day
- Weight:
- 0.28 LBS
- MATERIAL:
- RUBBER
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
MSRP: $73.95Now: $67.00Was: $73.95 -
On Sale
ATHENA Top End Gasket Kit - Yamaha P400485600039
ATHENA
MSRP: $79.95Now: $72.00Was: $79.95When you're preparing for race day, a fresh top end is non-negotiable. The ATHENA Top End Gasket Kit gives you the flexibility to optimize your engine for either pump gas with stock compression or unleash higher compression with race fuel—letting you...09342534- SKU:
- 09342534
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- TOP END
MSRP: $79.95Now: $72.00Was: $79.95Qty in Cart: 0Quantity:Price:MSRP: $79.95Now: $72.00Was: $79.95Subtotal: -
On Sale
ATHENA Top End Gasket Kit - Kawasaki P400250600024
ATHENA
MSRP: $86.95Now: $78.00Was: $86.95A top-end gasket kit is essential maintenance for any engine rebuild or mid-season refresh, especially when you're preparing for race day. The ATHENA P400250600024 gives you the flexibility to run either standard fuel with stock compression or premium...09342533- SKU:
- 09342533
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- TYPE:
- TOP END
- MATERIAL:
- RUBBER
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
MSRP: $86.95Now: $78.00Was: $86.95 -
K&S TECHNOLOGIES Water Pump Repair Kit 75-6001
K&S TECHNOLOGIES
$20.95A failing water pump can quickly turn a race day into a costly disaster. This K&S Technologies repair kit gives you everything needed to restore your pump to factory specifications without replacing the entire assembly, saving time and money while...09342527- SKU:
- 09342527
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- TYPE:
- WATER PUMP REPAIR
- UNITS:
- KIT
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- GASKET KIT
$20.95Qty in Cart: 0Quantity:Price:$20.95Subtotal: -
COMETIC Top End Gasket Set C3174-EST
COMETIC
$91.95A failing head gasket will leave you stranded, and factory gaskets simply can't handle the pressures of high-output 4-stroke engines. The COMETIC C3174-EST Top End Gasket Set uses multi-layered steel construction with proprietary Viton rubber coating to...09342432- SKU:
- 09342432
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- TYPE:
- TOP END
- UNITS:
- KIT
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 77.00 MM
- PRODUCT NAME:
- GASKET KIT
$91.95Qty in Cart: 0Quantity:Price:$91.95Subtotal: -
COMETIC Top End Gasket Set C3268-EST
COMETIC
$84.95A failing head gasket can cost you an entire season. The COMETIC C3268-EST Top End Gasket Set uses multi-layered steel construction with Viton rubber coating to handle extreme cylinder pressures—whether you're running naturally aspirated or boosted power...09342420- SKU:
- 09342420
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- PRODUCT NAME:
- GASKET KIT
- BORE SIZE METRIC:
- 96.00 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- TOP END
$84.95 -
COMETIC Top End Gasket Set C3267-EST
COMETIC
$91.95High-output 4-stroke engines demand gasket technology that can withstand extreme combustion pressures and heat cycles without compromising the seal. COMETIC's EST gasket set uses multi-layered steel construction with proprietary Viton rubber coating to...09342414- SKU:
- 09342414
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
- BORE SIZE METRIC:
- 78.00 MM
- TYPE:
- TOP END
$91.95Qty in Cart: 0Quantity:Price:$91.95Subtotal: -
COMETIC Top End Gasket Set C7924-EST
COMETIC
$98.95If you're running a high-output 4-stroke engine—whether naturally aspirated or boosted—a quality gasket set is non-negotiable for reliability and performance. The COMETIC C7924-EST combines multi-layered steel construction with EST (Extreme Sealing...09342410- SKU:
- 09342410
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- BORE SIZE METRIC:
- 87.00 MM
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- ATV
- TYPE:
- TOP END
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$98.95Qty in Cart: 0Quantity:Price:$98.95Subtotal: -
COMETIC Top End Gasket Set C3187-EST
COMETIC
$64.95A quality top-end gasket set is non-negotiable for any engine rebuild or refresh—poor sealing leads to compression loss, oil weeping, and catastrophic failure under boost or high RPM. The COMETIC C3187-EST uses multi-layered steel construction with Viton...09342405- SKU:
- 09342405
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- BORE SIZE METRIC:
- 66.00 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- TOP END
$64.95Qty in Cart: 0Quantity:Price:$64.95Subtotal: -
COMETIC Top End Gasket Set C3416
COMETIC
$44.95A failed head gasket can sideline your engine and drain your wallet fast. The COMETIC C3416 Top End Gasket Set uses multi-layered steel construction with Viton rubber coating to handle the extreme pressures of today's high-output 4-stroke engines—whether...09342395- SKU:
- 09342395
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- BORE SIZE METRIC:
- 45.00 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- TOP END
- PRODUCT NAME:
- GASKET KIT
$44.95 -
Cylinder Works Big Bore Gasket Kit Yamaha YFZ450 2004-2009 2012-2013 23001-G01
CYLINDER WORKS
$112.95When you're pushing your YFZ450 to its limits, stock cylinder components become your bottleneck. The Cylinder Works Big Bore Gasket Kit delivers measurable gains in displacement and power without requiring extensive machine work or re-plating—just bolt...09342387- SKU:
- 09342387
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- RIDING STYLE:
- UTV
- TYPE:
- TOP END
- PRODUCT NAME:
- GASKET KIT
- STYLE:
- BIG BORE
- UNITS:
- KIT
$112.95Qty in Cart: 0Quantity:Price:$112.95Subtotal: -
Cylinder Works Big Bore Gasket Kit 79mm Bore 2005-2012 KTM 250 SX-F 51002-G01
CYLINDER WORKS
$143.95If you're running a 2005-2012 KTM 250 SX-F and want measurable gains in displacement, durability, and reliability without extensive machine work, a big bore kit is the most direct path forward. This Cylinder Works system delivers a complete 79mm bore...09342370- SKU:
- 09342370
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- MATERIAL:
- NICKEL SILICON CARBIDE
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- BIG BORE
- UNITS:
- KIT
- TYPE:
- TOP END
$143.95 -
Cylinder Works Big Bore Gasket Kit KTM 350 SX-F 2011-2012 51001-G01
CYLINDER WORKS
$149.95If you're running a KTM 350 SX-F and looking to extract real performance gains, a big bore kit is one of the most effective bolt-on upgrades available. This Cylinder Works system delivers increased displacement and compression without requiring machine...09342369- SKU:
- 09342369
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- MATERIAL:
- NICKEL SILICON CARBIDE
- STYLE:
- BIG BORE
- TYPE:
- TOP END
- PRODUCT NAME:
- GASKET KIT
$149.95 -
On Sale
ATHENA Top End Gasket Kit - KTM P400270600028
ATHENA
MSRP: $77.95Now: $70.00Was: $77.95Engine refresh cycles are critical to maintaining peak performance between races, and the ATHENA Top End Gasket Kit gives you the flexibility to tune your compression ratio based on fuel availability and track conditions. Whether you're running on pump...09342346- SKU:
- 09342346
- Availability:
- Ships Same Business Day
- Weight:
- 0.18 LBS
- TYPE:
- TOP END
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
MSRP: $77.95Now: $70.00Was: $77.95 -
On Sale
ATHENA Top End Gasket Kit - KTM P400270600045
ATHENA
MSRP: $50.95Now: $46.00Was: $50.95Whether you're prepping for race day or executing a midseason engine refresh, the ATHENA Top End Gasket Kit gives you the flexibility to dial in your compression ratio without a full rebuild. Choose standard fuel with stock compression for reliability,...09342341- SKU:
- 09342341
- Availability:
- Ships Same Business Day
- Weight:
- 0.13 LBS
- UNITS:
- KIT
- TYPE:
- TOP END
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
MSRP: $50.95Now: $46.00Was: $50.95Qty in Cart: 0Quantity:Price:MSRP: $50.95Now: $46.00Was: $50.95Subtotal: -
On Sale
ATHENA Complete Gasket Kit - KTM P400270850045
ATHENA
MSRP: $116.95Now: $105.00Was: $116.95A complete engine rebuild demands gaskets that won't fail under extreme operating conditions. The ATHENA Complete Gasket Kit delivers OEM-equivalent sealing integrity with materials engineered to handle sustained high temperatures and pressure cycles...09342337- SKU:
- 09342337
- Availability:
- Ships Same Business Day
- Weight:
- 0.32 LBS
- RIDING STYLE:
- STREET
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- ENGINE TYPE:
- -
- UNITS:
- KIT
MSRP: $116.95Now: $105.00Was: $116.95 -
On Sale
ATHENA Gasket Kit - CRF150R P400210160019
ATHENA
MSRP: $64.95Now: $58.00Was: $64.95The ATHENA Gasket Kit is engineered for riders who demand reliability and thermal stability from their CRF150R. Factory gaskets degrade under sustained heat and load—this complete kit replaces worn sealing surfaces and pairs with an optimized aluminum...09341968- SKU:
- 09341968
- Availability:
- Ships Same Business Day
- Weight:
- 0.12 LBS
- PRODUCT NAME:
- GASKET KIT
- BORE SIZE METRIC:
- 69.00 MM
- TYPE:
- TOP END
- BORE SIZE:
- 69,00 MM
- DISPLACEMENT:
- 163.5 CC
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $64.95Now: $58.00Was: $64.95 -
On Sale
ATHENA Complete Gasket Kit - Kawasaki P400250850024
ATHENA
MSRP: $185.95Now: $167.00Was: $185.95A complete gasket kit is essential for any top-end or full engine rebuild—worn gaskets are a leading cause of compression loss, oil leaks, and coolant seepage that compromise performance and reliability. The ATHENA P400250850024 delivers OEM-quality...09341964- SKU:
- 09341964
- Availability:
- Ships Same Business Day
- Weight:
- 0.38 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
- RIDING STYLE:
- STREET
- ENGINE TYPE:
- -
- PRODUCT NAME:
- GASKET KIT
MSRP: $185.95Now: $167.00Was: $185.95 -
Cylinder Works Standard Bore Gasket Kit 810944
CYLINDER WORKS
$80.70A worn or damaged gasket kit compromises compression, increases blow-by, and accelerates engine wear—costing you performance and reliability. The Cylinder Works Standard Bore Gasket Kit 810944 delivers a complete, matched-component solution that restores...09341939- SKU:
- 09341939
- Availability:
- Ships Same Business Day
- Weight:
- 0.17 LBS
- STYLE:
- STANDARD
- TYPE:
- TOP END
- UNITS:
- KIT
- MATERIAL:
- NICKEL SILICON CARBIDE
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- ATV
$80.70 -
K&S TECHNOLOGIES Water Pump Repair Gasket Kit - YZ250F 75-4004
K&S TECHNOLOGIES
$35.65A leaking water pump can compromise your YZ250F's cooling system and derail race day performance. This K&S Technologies gasket kit supplies all OEM-spec seals and O-rings needed to restore a watertight seal without replacing the entire pump assembly. Get...09341924- SKU:
- 09341924
- Availability:
- Ships Same Business Day
- Weight:
- 0.22 LBS
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP REPAIR
- UNITS:
- KIT
$35.65Qty in Cart: 0Quantity:Price:$35.65Subtotal:
