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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HOT RODS Seal Output Shaft OSK0023
HOT RODS
$27.95A leaking countershaft seal doesn't just waste oil—it compromises engine reliability and can lead to catastrophic bearing failure if left unaddressed. The HOT RODS Seal Output Shaft kit eliminates...09350587- SKU:
- 09350587
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- SEAL
- APPLICATION:
- COUNTERSHAFT
- APPLICATION:
- TRANSMISSION
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$27.95 -
HOT RODS Seal Output Shaft OSK0022
HOT RODS
$31.95A leaking countershaft seal doesn't just cost you performance—it costs you money in fluid loss and risks catastrophic damage to your transmission. The HOT RODS Seal Output Shaft kit gives you...09350586- SKU:
- 09350586
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- APPLICATION:
- COUNTERSHAFT
- APPLICATION:
- TRANSMISSION
- PRODUCT NAME:
- SEAL
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$31.95 -
HOT RODS Seal Output Shaft OSK0016
HOT RODS
$35.95A leaking countershaft seal will compromise your transmission's integrity and lead to costly damage if left unaddressed. The HOT RODS Seal Output Shaft kit eliminates guesswork by bundling everything...09350581- SKU:
- 09350581
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- SEAL
- APPLICATION:
- COUNTERSHAFT
- APPLICATION:
- TRANSMISSION
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$35.95 -
On Sale
ATHENA Water Pump Gasket Kit - KTM P400270475001
ATHENA
MSRP: $37.95Now: $34.00Was: $37.95Coolant leaks and seal failures can sideline your KTM mid-season, compromising engine reliability when you need it most. The ATHENA Water Pump Gasket Kit provides OEM-spec replacement seals and...09346063- SKU:
- 09346063
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- WATER PUMP
MSRP: $37.95Now: $34.00Was: $37.95 -
On Sale
ATHENA Water Pump Gasket Kit - Kawasaki P400250475009
ATHENA
MSRP: $50.95Now: $46.00Was: $50.95Coolant leaks and seal failures can compromise engine temperature control and lead to costly damage. The ATHENA Water Pump Gasket Kit provides OEM-equivalent sealing components engineered to...09346057- SKU:
- 09346057
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
MSRP: $50.95Now: $46.00Was: $50.95 -
On Sale
ATHENA Water Pump Gasket Kit - Honda P400210475012
ATHENA
MSRP: $33.95Now: $31.00Was: $33.95A failing water pump gasket kit leads to coolant leaks, overheating, and potential engine damage—issues that sideline your vehicle and compromise reliability. The ATHENA P400210475012 kit eliminates...09346048- SKU:
- 09346048
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
MSRP: $33.95Now: $31.00Was: $33.95 -
On Sale
COMETIC Bottom End Gasket Set - Yamaha C7507BE
COMETIC
MSRP: $90.95Now: $81.86Was: $90.95A complete bottom end gasket set is essential for any serious engine rebuild—it ensures proper sealing across all critical oil passages, drain points, and water circulation routes. Using...09344304- SKU:
- 09344304
- Availability:
- Ships Same Business Day
- Weight:
- 0.55 LBS
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- BOTTOM END
- MODEL:
- HI-PERFORMANCE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $90.95Now: $81.86Was: $90.95 -
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: $96.95Now: $87.00Was: $96.95When 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: $96.95Now: $87.00Was: $96.95 -
On Sale
ATHENA Top End Gasket Kit - Honda P400210600202
ATHENA
MSRP: $58.95Now: $53.00Was: $58.95A 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: $58.95Now: $53.00Was: $58.95 -
On Sale
COMETIC Bottom End Gasket Set C3299
COMETIC
MSRP: $15.95Now: $14.36Was: $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
MSRP: $15.95Now: $14.36Was: $15.95 -
On Sale
ATHENA Complete Gasket Kit - KTM P400270850019
ATHENA
MSRP: $142.95Now: $129.00Was: $142.95A 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: $142.95Now: $129.00Was: $142.95 -
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 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 -
Hot Cams Valve Shim 9.48 x 2.80 for Honda CRF450R 2002-2014 5PK948280
HOT CAMS
$10.95Valve clearance directly impacts combustion efficiency, engine longevity, and power delivery—and shims are the most reliable way to dial in precise adjustments on your CRF450R. Whether you're...09261404- SKU:
- 09261404
- Availability:
- Ships Same Business Day
- Weight:
- 0.06 LBS
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
- VALVE SHIM THICKNESS METRIC:
- 2.80 MM
- RIDING STYLE:
- STREET
- MATERIAL:
- STEEL
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- SNOW
- UNITS:
- 5 PACK
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
$10.95 -
Hot Cams Valve Shim 9.48mm x 2.75mm for Honda CRF450R 2002-2014 5PK948275
HOT CAMS
$10.95Valve clearance directly impacts combustion efficiency, fuel economy, and engine longevity—and worn or incorrect shims will throw off those critical tolerances. The Hot Cams 9.48mm x 2.75mm shim pack...09261403- SKU:
- 09261403
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
- MATERIAL:
- STEEL
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- SNOW
- UNITS:
- 5 PACK
- RIDING STYLE:
- STREET
- VALVE SHIM THICKNESS METRIC:
- 2.75 MM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
$10.95 -
Hot Cams Valve Shim 9.48 x 2.70 for Honda CRF450R 2002-2014 5PK948270
HOT CAMS
$10.95Valve clearance directly impacts engine efficiency, fuel atomization, and overall performance—and worn or incorrect shims throw off that critical tolerance. The HOT CAMS Valve Shim 9.48 x 2.70 mm...09261402- SKU:
- 09261402
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- TYPE:
- VALVE
- RIDING STYLE:
- ATV
- RIDING STYLE:
- STREET
- VALVE SHIM THICKNESS METRIC:
- 2.70 MM
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- SNOW
- UNITS:
- 5 PACK
- MATERIAL:
- STEEL
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
$10.95 -
Hot Cams Valve Shim 9.48mm x 2.50mm for Honda CRF 450R 2002-2014 5PK948250
HOT CAMS
$10.95Valve clearance directly impacts combustion efficiency, valve longevity, and overall engine reliability—especially in high-performance applications where tolerances are critical. This HOT CAMS shim...09261398- SKU:
- 09261398
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- STREET
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 2.50 MM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- ATV
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- VALVE
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
$10.95 -
Hot Cams Valve Shim 8.90mm x 2.12mm KTM 250 SX-F 2005-2011 5PK890212
HOT CAMS
$11.95Valve clearance drift is inevitable on high-revving four-strokes like the KTM 250 SX-F—even small deviations compromise combustion efficiency and can lead to bent valves or loss of power. These Hot...09261359- SKU:
- 09261359
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- MATERIAL:
- STEEL
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- SNOW
- UNITS:
- 5 PACK
- RIDING STYLE:
- STREET
- VALVE SHIM THICKNESS METRIC:
- 2.12 MM
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
$11.95
