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 - Honda C7278
COMETIC
$42.95A quality gasket set is non-negotiable for reliable top-end performance, especially when running high-horsepower builds or forced induction. The COMETIC C7278 uses multi-layered steel construction...09344269- SKU:
- 09344269
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- BORE SIZE METRIC:
- 71.00 MM
- THICKNESS IMPERIAL:
- 0,012'
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- TOP END
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- THICKNESS METRIC:
- 0.31 MM
$42.95Qty in Cart: 0Quantity:Price:$42.95Subtotal: -
HOT RODS Water Pump Repair Kit - Honda WPK0003
HOT RODS
$63.95A failing water pump doesn't just compromise cooling efficiency—it risks catastrophic engine damage if ignored. This repair kit addresses the root causes of pump failure by replacing worn bearings...09342915- SKU:
- 09342915
- Availability:
- Ships Same Business Day
- Weight:
- 0.12 LBS
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- WATER PUMP REPAIR
- UNITS:
- KIT
- RIDING STYLE:
- OFF-ROAD
$63.95 -
On Sale
ATHENA Top End Gasket Kit - Yamaha P400485600069
ATHENA
MSRP: $101.95Now: $87.00Was: $101.95When you're prepping your engine for race day, a quality gasket kit is non-negotiable—it's your seal against compression loss and mid-race failures. The ATHENA Top End Gasket Kit gives you the...09342581- SKU:
- 09342581
- Availability:
- Ships Same Business Day
- Weight:
- 0.21 LBS
- TYPE:
- TOP END
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- ATV
MSRP: $101.95Now: $87.00Was: $101.95 -
On Sale
ATHENA Complete Gasket Kit - Honda P400210850202
ATHENA
MSRP: $164.95Now: $148.00Was: $164.95A complete engine rebuild demands gasket integrity that won't compromise under sustained load and heat—this Athena kit delivers the precision sealing your top-end rebuild requires. Whether you're...09342541- SKU:
- 09342541
- Availability:
- Ships Same Business Day
- Weight:
- 0.28 LBS
- PRODUCT NAME:
- GASKET KIT
- ENGINE TYPE:
- -
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
MSRP: $164.95Now: $148.00Was: $164.95Qty in Cart: 0Quantity:Price:MSRP: $164.95Now: $148.00Was: $164.95Subtotal: -
On Sale
ATHENA Top End Gasket Kit - Honda P400210600187
ATHENA
MSRP: $84.95Now: $76.00Was: $84.95Whether you're prepping for race day or executing a midseason engine refresh, the ATHENA Top End Gasket Kit delivers the precision sealing your engine demands. This kit is engineered for riders who...09342540- SKU:
- 09342540
- Availability:
- Ships Same Business Day
- Weight:
- 0.19 LBS
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- TOP END
MSRP: $84.95Now: $76.00Was: $84.95Qty in Cart: 0Quantity:Price:MSRP: $84.95Now: $76.00Was: $84.95Subtotal: -
On Sale
ATHENA Top End Gasket Kit - KTM P400270600056
ATHENA
MSRP: $96.95Now: $87.00Was: $96.95When you're prepping for race day—whether it's your first season or your hundredth—a fresh top end gasket kit is non-negotiable. The ATHENA P400270600056 gives you the flexibility to run either pump...09342539- SKU:
- 09342539
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
MSRP: $96.95Now: $87.00Was: $96.95Qty in Cart: 0Quantity:Price:MSRP: $96.95Now: $87.00Was: $96.95Subtotal: -
On Sale
ATHENA Top End Gasket Kit - Honda P400210600202
ATHENA
MSRP: $61.95Now: $53.00Was: $61.95A top-end refresh is essential before competition season, and the ATHENA Top End Gasket Kit delivers the precision sealing your engine needs for consistent performance and reliability. This kit gives...09342538- SKU:
- 09342538
- Availability:
- Ships Same Business Day
- Weight:
- 0.19 LBS
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- TOP END
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $61.95Now: $53.00Was: $61.95 -
COMETIC Bottom End Gasket Set C3299
COMETIC
$15.95Engine seals and gaskets are critical wear items that degrade with heat cycles and age—compromised bottom end gaskets lead to oil leaks, contamination, and catastrophic engine failure. The COMETIC...09342514- SKU:
- 09342514
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- PRODUCT NAME:
- GASKET KIT
- MODEL:
- HI-PERFORMANCE
- TYPE:
- BOTTOM END
- BORE SIZE METRIC:
- 55.00 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$15.95 -
COMETIC Top End Gasket Set C3395-EST
COMETIC
$68.95A quality gasket set is non-negotiable when rebuilding a high-performance top end—improper sealing leads to compression loss, coolant weeps, and catastrophic engine failure. The COMETIC C3395-EST...09342451- SKU:
- 09342451
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- PRODUCT NAME:
- GASKET KIT
- BORE SIZE IMPERIAL:
- 3.819'
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- TOP END
$68.95Qty in Cart: 0Quantity:Price:$68.95Subtotal: -
COMETIC Top End Gasket Set C7944-EST
COMETIC
$84.95A failing top-end gasket doesn't just leak—it compromises combustion sealing, kills ring seal efficiency, and can cascade into catastrophic engine damage. The COMETIC C7944-EST uses Multi-Layer Steel...09342426- SKU:
- 09342426
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- TOP END
- BORE SIZE METRIC:
- 95.00 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- RIDING STYLE:
- ATV
- RIDING STYLE:
- STREET
$84.95 -
Cylinder Works Big Bore Gasket Kit for 2010-2017 Honda CRF250R 11007-G01
CYLINDER WORKS
$75.95When you're ready to unlock serious power gains on your CRF250R, you need a big bore kit that actually delivers—without the headache of machine work or expensive re-plating. The Cylinder Works...09342383- SKU:
- 09342383
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- MATERIAL:
- NICKEL SILICON CARBIDE
- BORE SIZE METRIC:
- OVERSIZED (+3.00 MM)
- TYPE:
- TOP END
- PRODUCT NAME:
- GASKET KIT
- STYLE:
- BIG BORE
$75.95Qty in Cart: 0Quantity:Price:$75.95Subtotal: -
Cylinder Works Big Bore Gasket Kit for 2009-2016 Kawasaki KX250F 31004-G01
CYLINDER WORKS
$92.95When you're pushing your KX250F to its limits, factory tolerances become your biggest constraint. The Cylinder Works Big Bore Gasket Kit delivers measurable displacement gains and improved combustion...09341929- SKU:
- 09341929
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- BORE SIZE METRIC:
- OVERSIZED (+3.00 MM)
- MATERIAL:
- NICKEL SILICON CARBIDE
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- BIG BORE
- UNITS:
- KIT
- TYPE:
- TOP END
$92.95Qty in Cart: 0Quantity:Price:$92.95Subtotal: -
On Sale
ATHENA Complete Gasket Kit - KTM P400270850019
ATHENA
MSRP: $150.95Now: $129.00Was: $150.95A complete engine rebuild demands gaskets that can handle extreme temperatures and sustained pressure without compromise. Athena's engineering ensures reliable sealing across all critical surfaces,...09341819- SKU:
- 09341819
- Availability:
- Ships Same Business Day
- Weight:
- 0.49 LBS
- RIDING STYLE:
- STREET
- TYPE:
- COMPLETE
- UNITS:
- KIT
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- GASKET KIT
MSRP: $150.95Now: $129.00Was: $150.95 -
On Sale
ATHENA Top End Gasket Kit P400270600220/1
ATHENA
MSRP: $51.95Now: $47.00Was: $51.95A top-end gasket kit is essential maintenance for any racer looking to extend engine life and maintain peak performance between rebuilds. The ATHENA P400270600220/1 gives you the flexibility to run...09340234- SKU:
- 09340234
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- PRODUCT NAME:
- GASKET KIT
- ENGINE TYPE:
- 2-STROKE
- MATERIAL:
- RUBBER
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
MSRP: $51.95Now: $47.00Was: $51.95Qty in Cart: 0Quantity:Price:MSRP: $51.95Now: $47.00Was: $51.95Subtotal: -
Cylinder Works Standard Bore Cylinder Kit for Polaris ACE 900 EPS 2016 60004-K02
CYLINDER WORKS
$1,060.95When your Polaris ACE 900 EPS starts showing signs of wear or you're looking to restore factory performance, a quality cylinder kit is essential. The Cylinder Works Standard Bore Cylinder eliminates...09310734- SKU:
- 09310734
- Availability:
- Ships Same Business Day
- Weight:
- 9.91 LBS
- COMPRESSION RATIO IMPERIAL:
- 10.5:1
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- CYLINDER DIAMETER METRIC:
- 93.00 MM
- STYLE:
- STANDARD
- UNITS:
- KIT
- CYLINDER DIAMETER:
- 93,00 MM
- DISPLACEMENT:
- STANDARD
- RIDING STYLE:
- UTV
- ENGINE TYPE:
- 4-CYCLE
- PRODUCT NAME:
- CYLINDER
$1,060.95Qty in Cart: 0Quantity:Price:$1,060.95Subtotal: -
Cylinder Works Standard Bore Cylinder Kit for Polaris RZR 900 2015-2016 60004
CYLINDER WORKS
$672.95The stock cylinder in your Polaris RZR 900 can wear rapidly under aggressive riding conditions, leading to power loss and increased friction. The Cylinder Works Standard Bore Cylinder Kit restores...09310733- SKU:
- 09310733
- Availability:
- Ships Same Business Day
- Weight:
- 7.15 LBS
- CYLINDER DIAMETER METRIC:
- 93.00 MM
- UNITS:
- EACH
- ENGINE TYPE:
- 4-CYCLE
- PRODUCT NAME:
- CYLINDER
- CYLINDER DIAMETER:
- 93,00 MM
- RIDING STYLE:
- UTV
- STYLE:
- STANDARD
$672.95 -
Cylinder Works Big Bore Cylinder Kit Yamaha YZ85 2002-2018 103.5cc 21007-K01
CYLINDER WORKS
$885.95If you're running a stock YZ85, you're leaving performance on the table. This big bore kit delivers a measurable increase in displacement and power output without requiring machine work or custom...09310346- SKU:
- 09310346
- Availability:
- Ships Same Business Day
- Weight:
- 3.60 LBS
- COMPRESSION RATIO IMPERIAL:
- 8.2:1
- ENGINE TYPE:
- 2-CYCLE
- PRODUCT NAME:
- CYLINDER KIT
- STYLE:
- BIG BORE
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- DISPLACEMENT:
- 103.5 CC
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- CYLINDER DIAMETER METRIC:
- 52.50 MM
- CYLINDER DIAMETER:
- 52,50 MM
- OVERBORE METRIC:
- +5.00 MM
$885.95Qty in Cart: 0Quantity:Price:$885.95Subtotal: -
Cylinder Works Suzuki RM-Z250 2010-2012 Standard Bore Cylinder Kit 40004-K01
CYLINDER WORKS
$704.95When your RM-Z250 cylinder shows signs of wear—scoring, loss of compression, or increased blow-by—a factory replacement often means sending your engine out for expensive machine work and re-plating...09310343- SKU:
- 09310343
- Availability:
- Ships Same Business Day
- Weight:
- 3.25 LBS
- COMPRESSION RATIO IMPERIAL:
- 13.4:1
- CYLINDER DIAMETER METRIC:
- 77.00 MM
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- STANDARD
- DISPLACEMENT:
- 249 CC
- ENGINE TYPE:
- 4-CYCLE
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- CYLINDER DIAMETER:
- 77,00 MM
- PRODUCT NAME:
- CYLINDER KIT
- UNITS:
- KIT
$704.95 -
Cylinder Works Kawasaki KX250F 2009 Standard Bore Cylinder Kit 30004-K01
CYLINDER WORKS
$679.95A worn or damaged cylinder compromises both power delivery and reliability—especially critical on a high-strung 250F that demands precision. This bolt-on Cylinder Works kit restores your engine to...09310277- SKU:
- 09310277
- Availability:
- Ships Same Business Day
- Weight:
- 3.15 LBS
- COMPRESSION RATIO IMPERIAL:
- 13.2:1
- CYLINDER DIAMETER METRIC:
- 77.00 MM
- RIDING STYLE:
- OFF-ROAD
- DISPLACEMENT:
- 249 CC
- ENGINE TYPE:
- 4-CYCLE
- STYLE:
- STANDARD
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- CYLINDER DIAMETER:
- 77,00 MM
- PRODUCT NAME:
- CYLINDER KIT
- UNITS:
- KIT
$679.95 -
On Sale
ATHENA Cylinder Kit - YZ250F - 83mm P400485100012
ATHENA
MSRP: $1,142.95Now: $1,029.00Was: $1,142.95If you're running a YZ250F at the edge of its limits, a worn or damaged cylinder is a performance killer that demands immediate attention. The ATHENA Cylinder Kit gives you OEM-quality reliability...09310024- SKU:
- 09310024
- Availability:
- Ships Same Business Day
- Weight:
- 3.68 LBS
- DISPLACEMENT:
- 290 CC
- ENGINE TYPE:
- 4-STROKE
- RIDING STYLE:
- OFF-ROAD
- MATERIAL:
- ALUMINUM
- BORE SIZE METRIC:
- 83.00 MM
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- PRODUCT NAME:
- CYLINDER KIT
- STYLE:
- BIG BORE
- UNITS:
- KIT
MSRP: $1,142.95Now: $1,029.00Was: $1,142.95Qty in Cart: 0Quantity:Price:MSRP: $1,142.95Now: $1,029.00Was: $1,142.95Subtotal:
