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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Wiseco Piston Kit Standard Yamaha YZ125 2005-2021 845M05400
WISECO
$143.95Your YZ125 piston is the foundation of engine reliability and power delivery—a worn or damaged unit tanks your throttle response and durability on the track. The Wiseco 845M05400 piston kit delivers precision-engineered construction with a tight...09100571- SKU:
- 09100571
- Availability:
- Ships Same Business Day
- Weight:
- 0.38 LBS
- PISTON MATERIAL:
- FORGED
- RIDING STYLE:
- OFF-ROAD
- STROKE LENGTH METRIC:
- 54.50 MM
- BORE SIZE METRIC:
- 54.00 MM
- MODEL:
- PRO-LITE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- BORE - OVERSIZE:
- STANDARD
- BORE - OVERSIZE METRIC:
- STANDARD
- DISPLACEMENT:
- 125 CC
- PRODUCT NAME:
- PISTON
- UNITS:
- EACH
$143.95Qty in Cart: 0Quantity:Price:$143.95Subtotal: -
Wiseco YZ85 2002-2018 Piston Kit with Gaskets PK1202
WISECO
$181.95The Wiseco PK1202 is engineered for YZ85 riders who demand reliable top-end performance without compromise. This complete piston kit delivers the precision bore diameter and optimized ring design necessary for consistent power delivery and throttle...09030299- SKU:
- 09030299
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
- BORE - OVERSIZE METRIC:
- STANDARD
- PRODUCT NAME:
- REBUILD KIT
- BORE - OVERSIZE:
- STANDARD
- ENGINE TYPE:
- 2-STROKE
- PISTON DIAMETER METRIC:
- 47.45 MM
- SKIRT COATING:
- NON-COATED
- BORE SIZE METRIC:
- 47.50 MM
- DISPLACEMENT:
- 85 CC
- PISTON MATERIAL:
- 4032 ALUMINUM ALLOY
- MODEL:
- PRO-LITE
- RIDING STYLE:
- OFF-ROAD
- STROKE LENGTH METRIC:
- 47.80 MM
- TYPE:
- TOP END
- UNITS:
- KIT
$181.95 -
K & N Oil Filter KN-207
K & N
$11.99Synthetic racing oils demand a filter engineered to match their performance characteristics—and the K&N KN-207 delivers exactly that. With a synthetic media designed to handle high concentrations of synthetic and blended oils, this filter maintains...07120033- SKU:
- 07120033
- Availability:
- Ships Same Business Day
- Weight:
- 0.07 LBS
- BASE COLOR:
- RED
- UNITS:
- EACH
- BASE FINISH:
- NATURAL
- COLOR/FINISH:
- RED
- FILTER MEDIA MATERIAL:
- SYNTHETIC
- LENGTH METRIC:
- 44 MM
- STYLE:
- STANDARD
- TYPE:
- CARTRIDGE
- PRODUCT NAME:
- OIL FILTER
- RIDING STYLE:
- OFF-ROAD
$11.99 -
Hot Cams Valve Shim 8.90mm x 2.52mm for KTM 250 SX-F 2005-2011 5PK890252
HOT CAMS
$11.95Valve shim clearance directly impacts combustion efficiency, valve timing accuracy, and engine longevity on high-revving 4-stroke engines like the KTM 250 SX-F. Over time, shims wear and compress, throwing off critical valve lash tolerances and robbing...09261369- SKU:
- 09261369
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
$11.95Qty in Cart: 0Quantity:Price:$11.95Subtotal: -
HOT RODS Main Bearing Seal Kit - Can-Am HR00101
HOT RODS
$123.95A quality main bearing seal kit is essential when rebuilding your crankshaft assembly—it ensures proper lubrication retention and prevents oil leakage that can compromise engine integrity. The HOT RODS Main Bearing Seal Kit for Can-Am delivers...09240639- SKU:
- 09240639
- Availability:
- Ships Same Business Day
- Weight:
- 0.55 LBS
$123.95 -
HOT RODS Main Bearing Seal Kit - Can-Am HR00102
HOT RODS
$190.95Main bearing seals are critical wear items that directly impact crankshaft longevity and engine reliability. Worn or degraded seals allow contaminants and oil leakage that accelerate bearing failure and compromise performance. This HOT RODS kit provides...09240640- SKU:
- 09240640
- Availability:
- Ships Same Business Day
- Weight:
- 0.60 LBS
$190.95 -
HOT RODS Plain Bearing Crankshaft - Can-Am HR00103
HOT RODS
$62.95A worn or damaged crankshaft compromises engine reliability and performance—forcing costly downtime and potential catastrophic failure. The HOT RODS Plain Bearing Crankshaft (HR00103) delivers OEM-equivalent durability with the precision engineering...09240641- SKU:
- 09240641
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
$62.95 -
HOT RODS Plain Bearing Crankshaft - Can-Am HR00104
HOT RODS
$62.95A worn or damaged crankshaft compromises engine reliability and performance across the board—throttle response suffers, bearing wear accelerates, and catastrophic failure becomes a real risk. The HOT RODS Plain Bearing Crankshaft (HR00104) is engineered...09240642- SKU:
- 09240642
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
$62.95 -
HOT RODS Connecting Rod Kit - Yamaha 8618
HOT RODS
$232.95When you're pushing your Yamaha engine to higher RPMs and demanding more from your build, factory connecting rods become your first limitation. The HOT RODS 8618 Kit replaces them with heavy-duty, precision-engineered components built to handle sustained...09230042- SKU:
- 09230042
- Availability:
- Ships Same Business Day
- Weight:
- 1.10 LBS
$232.95 -
HOT RODS Connecting Rod Kit - Can- Am HR00062
HOT RODS
$212.95High-RPM reliability demands a connecting rod built to withstand extreme stress without compromise. The HOT RODS Connecting Rod Kit delivers OE-grade durability with engineering refinements designed specifically for sustained performance at elevated...09210884- SKU:
- 09210884
- Availability:
- Ships Same Business Day
- Weight:
- 1.40 LBS
$212.95 -
HOT RODS Crankshaft Assembly - OEM Stroke - Can-Am HR00064
HOT RODS
$1,034.95Your engine's crankshaft is the foundation of reliability and performance. A compromised crank means lost power, instability, and potential catastrophic failure. The HOT RODS Crankshaft Assembly delivers OEM-equivalent durability while maintaining...09210886- SKU:
- 09210886
- Availability:
- Ships Same Business Day
- Weight:
- 15.70 LBS
$1,034.95 -
HOT RODS Crankshaft Assembly - OEM Stroke - Polaris HR00027
HOT RODS
$1,006.95A crankshaft assembly is the backbone of your engine's reliability and performance—especially in high-demand racing applications where factory components often can't keep pace. The HOT RODS Crankshaft Assembly delivers OEM-stroke performance while...09210887- SKU:
- 09210887
- Availability:
- Ships Same Business Day
- Weight:
- 15.30 LBS
$1,006.95 -
HOT RODS Bottom End Kit - OE Crankshaft Replacement - Honda HR00105
HOT RODS
$662.95A complete bottom-end rebuild requires precision components and meticulous attention to detail—this kit eliminates guesswork by bundling everything you need for a proper crankshaft replacement in one package. Whether you're refreshing a high-mileage...09210889- SKU:
- 09210889
- Availability:
- Ships Same Business Day
- Weight:
- 13.50 LBS
$662.95 -
HOT RODS Bottom End Kit - OE Crankshaft Replacement - Polaris HR00108
HOT RODS
$1,591.95A complete bottom-end rebuild requires precision components and proper sealing to ensure reliability under load. This HOT RODS kit eliminates guesswork by combining OE-specification crankshaft replacement parts with HOT RODS main bearings and a...09210892- SKU:
- 09210892
- Availability:
- Ships Same Business Day
- Weight:
- 29.90 LBS
$1,591.95 -
HOT RODS Bottom End Kit - OE Crankshaft Replacement - Polaris HR00110
HOT RODS
$1,591.95A complete crankshaft replacement demands precision components and proper sealing—this kit eliminates the guesswork by bundling everything you need in one package. Whether you're rebuilding after catastrophic failure or performing preventive maintenance,...09210893- SKU:
- 09210893
- Availability:
- Ships Same Business Day
- Weight:
- 28.00 LBS
$1,591.95 -
HOT RODS Bottom End Kit - OE Crankshaft Replacement - Polaris HR00111
HOT RODS
$1,591.95A complete bottom-end rebuild requires precision components and proper sealing—this kit eliminates the guesswork by bundling everything needed for a reliable crankshaft replacement. Whether you're refreshing a worn engine or building a fresh long-block,...09210894- SKU:
- 09210894
- Availability:
- Ships Same Business Day
- Weight:
- 27.45 LBS
$1,591.95 -
HOT RODS Bottom End Kit - OE Crankshaft Replacement - Polaris HR00120
HOT RODS
$1,360.95A failed or worn crankshaft compromises engine reliability and performance across the board. This complete bottom end kit eliminates guesswork by bundling OE-spec components—main bearings, seals, and a full gasket set—so you can execute a comprehensive...09210899- SKU:
- 09210899
- Availability:
- Ships Same Business Day
- Weight:
- 24.05 LBS
$1,360.95 -
HOT RODS Connecting Rod Bolt Kit - Can-Am HR00092
HOT RODS
$64.95A complete engine rebuild demands precision fastening, and connecting rod bolts are critical to maintaining proper clamping force and structural integrity under extreme combustion pressures. Using OEM-spec HOT RODS connecting rod bolts ensures your...09230633- SKU:
- 09230633
- Availability:
- Ships Same Business Day
- Weight:
- 0.45 LBS
$64.95 -
HOT RODS Crankshaft Kit - OE Crankshaft Replacement - Suzuki CBK0081
HOT RODS
$622.95A worn or damaged crankshaft compromises your entire engine's reliability and performance. The HOT RODS Crankshaft Kit delivers factory-spec precision with the added durability of professional-grade manufacturing, ensuring your Suzuki engine runs true...09210328- SKU:
- 09210328
- Availability:
- Ships Same Business Day
- Weight:
- 9.10 LBS
$622.95 -
HOT RODS Crankshaft Kit - OE Crankshaft Replacement - Kawasaki CBK0118
HOT RODS
$795.95A crankshaft failure means complete engine shutdown—and an expensive rebuild. The HOT RODS Crankshaft Kit gives you a factory-spec replacement that's assembled, inspected, and ready to bolt in, restoring your Kawasaki to full performance without...09210355- SKU:
- 09210355
- Availability:
- Ships Same Business Day
- Weight:
- 13.35 LBS
$795.95
