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
-
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 -
VERTEX Ring Set 590295500001
VERTEX
$80.95OEM piston rings wear down with every combustion cycle, causing blow-by, power loss, and increased oil consumption. The VERTEX Ring Set 590295500001 delivers nitride-coated or chrome-plated surfaces...09120218- SKU:
- 09120218
- Availability:
- Ships Same Business Day
- Weight:
- 0.06 LBS
- PRODUCT NAME:
- PISTON RING
- RIDING STYLE:
- ATV
- UNITS:
- SET
- PISTON DIAMETER METRIC:
- 95.45 MM
$80.95 -
VERTEX Ring Set 590296000001
VERTEX
$82.95Piston rings are the critical seal between your combustion chamber and crankcase—when they wear, you lose compression, power, and efficiency. VERTEX's nitride-coated and chrome-plated ring sets...09120219- SKU:
- 09120219
- Availability:
- Ships Same Business Day
- Weight:
- 0.07 LBS
- PISTON DIAMETER METRIC:
- 95.96 MM
- UNITS:
- SET
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- PISTON RING
$82.95 -
VERTEX Piston Kit 23335A
VERTEX
$197.95Premium pistons are the foundation of any high-performance engine build, and the VERTEX Piston Kit 23335A delivers the durability and precision needed for sustained power output and reliable...09100967- SKU:
- 09100967
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- PRODUCT NAME:
- PISTON KIT
- BORE - OVERSIZE:
- +4,00 MM
- BORE - OVERSIZE METRIC:
- +4.00 MM
- DISPLACEMENT:
- 144 CC
- PISTON MATERIAL:
- CAST
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- CAST BIG BORE
- UNITS:
- KIT
- ENGINE TYPE:
- 2-STROKE
- PISTON DIAMETER METRIC:
- 57.95 MM
- COMPRESSION RATIO IMPERIAL:
- STANDARD
- CYLINDER DIAMETER METRIC:
- 58.00 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
$197.95 -
VERTEX Piston Kit 24275B
VERTEX
$322.95Whether you're rebuilding a two-stroke or refreshing a four-stroke top end, the VERTEX Piston Kit 24275B delivers the precision and durability required for consistent performance across your entire...09105132- SKU:
- 09105132
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
- COMPRESSION RATIO IMPERIAL:
- 14.2:1
- DISPLACEMENT:
- 250 CC
- PISTON DIAMETER METRIC:
- 78.97 MM
- CYLINDER DIAMETER METRIC:
- 79 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- PRODUCT NAME:
- PISTON KIT
- STYLE:
- GP RACER'S CHOICE
- ENGINE TYPE:
- 4-STROKE
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
$322.95
