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!
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- Price
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PROX Connecting Rod Kit - Honda CRF450R 03.1417
PROX
$183.95A connecting rod is the critical link between your crankshaft and piston—when it fails, your engine fails. The PROX Connecting Rod Kit for Honda CRF450R delivers the strength and precision needed for...09230460- SKU:
- 09230460
- Availability:
- Ships Same Business Day
- Weight:
- 1.50 LBS
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$183.95 -
PROX Connecting Rod Kit - Honda CRF150R 03.1227
PROX
$131.95A worn or damaged connecting rod compromises power delivery and risks catastrophic engine failure. The PROX Connecting Rod Kit for Honda CRF150R delivers OEM-quality reliability with...09230237- SKU:
- 09230237
- Availability:
- Ships Same Business Day
- Weight:
- 0.74 LBS
- ENGINE TYPE:
- 2-STROKE
- MATERIAL:
- FORGED
- MATERIAL:
- STEEL
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$131.95 -
PROX Connecting Rod Kit 03.1660
PROX
$197.95A connecting rod kit is fundamental to engine reliability and power delivery—it's the critical link between your crankshaft and piston, transferring combustion forces with precision. The PROX 03.1660...09230241- SKU:
- 09230241
- Availability:
- Ships Same Business Day
- Weight:
- 2.27 LBS
- ENGINE TYPE:
- 4-STROKE
- MATERIAL:
- FORGED STEEL
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$197.95 -
PROX Connecting Rod Kit 03.4409
PROX
$183.95A connecting rod kit is the critical link between your engine's piston and crankshaft—any flex, wear, or imbalance directly compromises power delivery and engine longevity. The PROX 03.4409 kit...09230245- SKU:
- 09230245
- Availability:
- Ships Same Business Day
- Weight:
- 1.63 LBS
- ENGINE TYPE:
- 4-STROKE
- MATERIAL:
- FORGED STEEL
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$183.95 -
PROX Connecting Rod Kit 03.6528
PROX
$188.95A quality connecting rod kit is fundamental to engine reliability and performance, especially under high RPM and boost conditions. The PROX 03.6528 delivers a complete assembly with...09230248- SKU:
- 09230248
- Availability:
- Ships Same Business Day
- Weight:
- 1.79 LBS
- UNITS:
- EACH
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- MATERIAL:
- FORGED STEEL
$188.95 -
PROX Connecting Rod 03.1212
PROX
$132.95A connecting rod is the critical mechanical bridge between your crankshaft and piston—any wear, flex, or misalignment directly tanks engine efficiency and reliability. The PROX 03.1212 delivers...09230126- SKU:
- 09230126
- Availability:
- Ships Same Business Day
- Weight:
- 0.72 LBS
- ENGINE TYPE:
- 2-STROKE
- FEATURES:
- INCLUDES THRUST WASHERS
- MATERIAL:
- FORGED STEEL
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$132.95 -
PROX Connecting Rod 03.2426
PROX
$183.95A quality connecting rod directly impacts engine reliability and power delivery—weak or worn rods risk catastrophic internal damage. The PROX Connecting Rod 03.2426 delivers precision engineering...09230183- SKU:
- 09230183
- Availability:
- Ships Same Business Day
- Weight:
- 1.51 LBS
- MATERIAL:
- FORGED STEEL
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- CONNECTING ROD KIT
$183.95 -
On Sale
PROX Piston Kit 01.1315.A1
PROX
MSRP: $139.95Now: $119.00Was: $139.95Whether you're rebuilding after race-induced wear or restoring your engine to factory performance, the PROX Piston Kit 01.1315.A1 delivers the precision and durability that competitive engines demand...PX4420B- SKU:
- PX4420B
- Availability:
- Ships Same Business Day
- Weight:
- 0.63 LBS
- PISTON DIAMETER METRIC:
- 66.35 MM
- PISTON SIZE METRIC:
- STANDARD SIZE A
- RIDING STYLE:
- OFF-ROAD
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- BORE SIZE METRIC:
- 66.35 MM
- PRODUCT NAME:
- PISTON KIT
MSRP: $139.95Now: $119.00Was: $139.95 -
On Sale
PROX Piston Kit 01.2217.D
PROX
MSRP: $121.95Now: $90.00Was: $121.95Worn or damaged pistons compromise engine efficiency, power delivery, and reliability—making a quality replacement essential for any serious build or rebuild. The PROX Piston Kit 01.2217.D delivers...PX7215D- SKU:
- PX7215D
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- RIDING STYLE:
- OFF-ROAD
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- BORE SIZE METRIC:
- 53.98 MM
- PISTON DIAMETER METRIC:
- 53.98 MM
- PISTON SIZE METRIC:
- STANDARD
MSRP: $121.95Now: $90.00Was: $121.95 -
On Sale
PROX Crank Seal Kit - KTM50 42.6011
PROX
MSRP: $16.95Now: $13.00Was: $16.95A worn crank seal kit is the silent killer of small-displacement performance. If you're rebuilding a KTM50 or experiencing oil weeping around the crankshaft, this OEM-quality seal kit eliminates...09350605- SKU:
- 09350605
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- TYPE:
- OIL
- PRODUCT NAME:
- SEAL
- APPLICATION:
- CRANKSHAFT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $16.95Now: $13.00Was: $16.95 -
On Sale
PROX Gasket Kit - Complete - Honda 34.1220
PROX
MSRP: $93.95Now: $76.00Was: $93.95A complete gasket kit is essential for any engine rebuild or head gasket replacement—it eliminates the risk of mixing incompatible components and ensures every sealing surface meets OEM...09345520- SKU:
- 09345520
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- ENGINE TYPE:
- 2-STROKE
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
MSRP: $93.95Now: $76.00Was: $93.95 -
On Sale
PROX Gasket Kit - Complete - Honda 34.1322
PROX
MSRP: $105.95Now: $85.00Was: $105.95A complete gasket kit is the foundation of a reliable engine rebuild or refresh. Over time, gaskets degrade and lose their sealing integrity, leading to oil leaks, coolant seepage, and potential...09345526- SKU:
- 09345526
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- GASKET KIT
MSRP: $105.95Now: $85.00Was: $105.95 -
On Sale
PROX Gasket Kit - Complete - Honda 34.1416
PROX
MSRP: $130.95Now: $106.00Was: $130.95A complete gasket kit is essential for any Honda engine rebuild or overhaul—it ensures a proper seal across all critical engine surfaces and eliminates the risk of oil leaks or compression loss that...09345535- SKU:
- 09345535
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
MSRP: $130.95Now: $106.00Was: $130.95 -
On Sale
PROX Gasket Kit - Complete - Kawasaki 34.4339
PROX
MSRP: $162.95Now: $132.00Was: $162.95A complete gasket kit is essential for any engine rebuild or top-end service—sealing failures can compromise compression, cause oil leaks, and degrade performance. The PROX Gasket Kit for Kawasaki...09345606- SKU:
- 09345606
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
MSRP: $162.95Now: $132.00Was: $162.95 -
On Sale
PROX Gasket Kit - Complete - KTM 34.6340
PROX
MSRP: $99.95Now: $81.00Was: $99.95A complete gasket kit is the foundation of a reliable engine rebuild or top-end refresh. Whether you're addressing a leak, performing preventive maintenance, or building a high-revving motor, having...09345633- SKU:
- 09345633
- Availability:
- Ships Same Business Day
- Weight:
- 0.35 LBS
- RIDING STYLE:
- STREET
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- COMPLETE
- UNITS:
- KIT
MSRP: $99.95Now: $81.00Was: $99.95 -
On Sale
PROX Top End Gasket Set - Kawasaki/Suzuki 35.4334
PROX
MSRP: $62.95Now: $51.00Was: $62.95A top-end gasket set is essential for maintaining compression integrity and preventing coolant or oil seepage in high-performance applications. PROX gaskets are engineered to OEM specifications with...09345766- SKU:
- 09345766
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- PRODUCT NAME:
- GASKET SET
- UNITS:
- SET
MSRP: $62.95Now: $51.00Was: $62.95 -
VERTEX Piston Kit - High Compression 24112A
VERTEX
$327.95High-compression pistons are critical for maximizing power output and engine efficiency in forced-induction and naturally-aspirated builds, and the VERTEX 24112A delivers the durability and precision...09104113- SKU:
- 09104113
- Availability:
- Ships Same Business Day
- Weight:
- 0.90 LBS
- COMPRESSION RATIO IMPERIAL:
- 13.6:1
- DISPLACEMENT:
- 450 CC
- PRODUCT NAME:
- PISTON KIT
- CYLINDER DIAMETER METRIC:
- 95.00 MM
- PISTON DIAMETER METRIC:
- 94.95 MM
- RIDING STYLE:
- STREET
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- ENGINE TYPE:
- 4-STROKE
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- FORGED HIGH COMPRESSION
- UNITS:
- KIT
$327.95 -
VERTEX Piston Kit VTK22995B
VERTEX
$197.95Precision-engineered pistons are the foundation of reliable high-RPM performance, and the VERTEX Piston Kit VTK22995B delivers the durability and longevity required for sustained racing and demanding...09103020- SKU:
- 09103020
- Availability:
- Ships Same Business Day
- Weight:
- 0.90 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- COMPRESSION RATIO IMPERIAL:
- STANDARD
- CYLINDER DIAMETER METRIC:
- 54.00 MM
- PRODUCT NAME:
- TOP END PISTON KIT
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- CAST REPLICA
- DISPLACEMENT:
- 125 CC
- ENGINE TYPE:
- 2-STROKE
- PISTON DIAMETER METRIC:
- 53.93 MM
- PISTON MATERIAL:
- CAST
- UNITS:
- KIT
$197.95 -
VERTEX Piston Ring - Lower 55910005800
VERTEX
$44.95Piston ring degradation directly impacts compression, blow-by rates, and overall engine efficiency—making a quality replacement critical for maintaining power output and engine longevity. The VERTEX...09120636- SKU:
- 09120636
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- PISTON RING
- UNITS:
- SET
- RIDING STYLE:
- OFF-ROAD
$44.95 -
VERTEX Ring Set 590280000002
VERTEX
$99.95Stock piston rings are often the first component to wear under high RPM and sustained load, leading to blow-by, compression loss, and accelerated engine degradation. The VERTEX Ring Set 590280000002...09120214- SKU:
- 09120214
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- UNITS:
- SET
- PRODUCT NAME:
- PISTON RING
- PISTON DIAMETER METRIC:
- 79.96 MM
- RIDING STYLE:
- OFF-ROAD
$99.95
