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 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
$98.95 -
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
$64.95 -
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 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: $50.95 -
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 -
COMETIC Gasket Set - 95 mm - Yamaha C7908-EST
COMETIC
$89.95A quality gasket set is non-negotiable when you're rebuilding a top end—it's the seal between raw power and catastrophic failure. The COMETIC C7908-EST delivers the sealing reliability you need for high-output 4-stroke engines, whether naturally...09340933- SKU:
- 09340933
- Availability:
- Ships Same Business Day
- Weight:
- 0.23 LBS
- BORE SIZE METRIC:
- 95.00 MM
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- STREET
- TYPE:
- TOP END
$89.95 -
COMETIC Gasket Set - 77 mm - Yamaha C7905-EST
COMETIC
$83.95High-output 4-stroke engines demand gasket solutions engineered for extreme cylinder pressures and heat cycles. The COMETIC C7905-EST Gasket Set delivers reliable sealing across naturally aspirated and forced-induction applications, preventing blowby and...09340932- SKU:
- 09340932
- Availability:
- Ships Same Business Day
- Weight:
- 0.19 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
- BORE SIZE METRIC:
- 77.00 MM
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- GASKET KIT
$83.95 -
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 construction with Extreme Sealing Technology (EST) to...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 -
On Sale
ATHENA Cylinder Gasket Kit - Yamaha 070203/1
ATHENA
MSRP: $14.95Now: $13.00Was: $14.95When 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 ATHENA Cylinder Gasket Kit 070203/1 is engineered...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: $14.95Now: $13.00Was: $14.95 -
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 OEM-equivalent gasket kit ensures a proper fit and long-term...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 construction with Viton rubber coating to handle extreme...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 WINDEROSA Top End Gasket Kit gives you all the critical...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 Cylinder Gasket Kit - KX125 P400250160001
ATHENA
MSRP: $57.95Now: $52.00Was: $57.95Maintain 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 coated aluminum cylinder and molybdenum-coated forged...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: $57.95Now: $52.00Was: $57.95 -
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 Vertex pistons are precision-matched to the cylinder,...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 jetting just to maintain baseline power. The Cylinder...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
