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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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 03.2440
PROX
$175.95A quality connecting rod kit is fundamental to engine reliability and power delivery—it's the critical link between your crankshaft and piston, and any weakness here compromises performance across...09230279- SKU:
- 09230279
- Availability:
- Ships Same Business Day
- Weight:
- 1.55 LBS
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- MATERIAL:
- FORGED STEEL
$175.95Qty in Cart: 0Quantity:Price:$175.95Subtotal: -
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 03.1402
PROX
$175.95A connecting rod is the critical link between your crankshaft and piston—it must handle extreme forces under high RPM without flexing or failure. The PROX 03.1402 delivers the reliability and...09230129- SKU:
- 09230129
- Availability:
- Ships Same Business Day
- Weight:
- 1.59 LBS
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- FEATURES:
- INCLUDES THRUST WASHERS
- MATERIAL:
- FORGED STEEL
- UNITS:
- EACH
$175.95Qty in Cart: 0Quantity:Price:$175.95Subtotal: -
PROX Connecting Rod 03.6023
PROX
$109.95A connecting rod is your engine's critical link between reciprocating piston motion and rotational crankshaft power. The PROX 03.6023 delivers OEM-quality construction with precision bearings...09230151- SKU:
- 09230151
- Availability:
- Ships Same Business Day
- Weight:
- 0.51 LBS
- UNITS:
- EACH
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- ENGINE TYPE:
- 2-STROKE
- MATERIAL:
- FORGED STEEL
$109.95Qty in Cart: 0Quantity:Price:$109.95Subtotal: -
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
$183.95Qty in Cart: 0Quantity:Price:$183.95Subtotal: -
PROX Connecting Rod 03.3108
PROX
$109.95A connecting rod is fundamental to engine reliability and performance—it transfers combustion force from the piston to the crankshaft, making it one of the most critical components in your engine...09230192- SKU:
- 09230192
- Availability:
- Ships Same Business Day
- Weight:
- 0.53 LBS
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- ENGINE TYPE:
- 2-STROKE
- MATERIAL:
- FORGED STEEL
$109.95Qty in Cart: 0Quantity:Price:$109.95Subtotal: -
PROX Connecting Rod 03.6351
PROX
$179.95A connecting rod is the critical link between your piston and crankshaft—any weakness here directly impacts power delivery, reliability, and engine longevity. The PROX Connecting Rod 03.6351 arrives...09230349- SKU:
- 09230349
- Availability:
- Ships Same Business Day
- Weight:
- 1.42 LBS
- ENGINE TYPE:
- 4-STROKE
- MATERIAL:
- FORGED STEEL
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$179.95Qty in Cart: 0Quantity:Price:$179.95Subtotal: -
PROX Piston Kit 01.1323.C
PROX
$139.95A piston kit is fundamental to engine reliability and performance—worn or damaged pistons compromise compression, increase blowby, and accelerate wear throughout your engine. The PROX Piston Kit 01...PX1322C- SKU:
- PX1322C
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- RIDING STYLE:
- OFF-ROAD
- PISTON SIZE METRIC:
- STANDARD SIZE C
- BORE SIZE METRIC:
- 66.36 MM
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- PISTON DIAMETER METRIC:
- 66.36 MM
$139.95Qty in Cart: 0Quantity:Price:$139.95Subtotal: -
PROX Ring Set 02.1208
PROX
$26.45Piston ring sets are critical to engine sealing and compression integrity—worn or damaged rings lead to blow-by, oil consumption, and power loss. The PROX Ring Set 02.1208 delivers OEM-level...PX4210R- SKU:
- PX4210R
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- SET
- PRODUCT NAME:
- PISTON RING
- RIDING STYLE:
- OFF-ROAD
$26.45Qty in Cart: 0Quantity:Price:$26.45Subtotal: -
PROX Piston Kit 01.1208.A1
PROX
$105.95When your engine's pistons wear beyond serviceable limits, you need a replacement that matches or exceeds OEM performance—not a compromise. The PROX Piston Kit 01.1208.A1 delivers factory-spec...PX4240B- SKU:
- PX4240B
- Availability:
- Ships Same Business Day
- Weight:
- 0.38 LBS
- PRODUCT NAME:
- PISTON KIT
- PISTON DIAMETER METRIC:
- 53.94 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- BORE SIZE METRIC:
- 53.94 MM
- PISTON SIZE METRIC:
- STANDARD SIZE A
- RIDING STYLE:
- OFF-ROAD
$105.95Qty in Cart: 0Quantity:Price:$105.95Subtotal: -
PROX Ring Set 02.1213
PROX
$24.95Piston rings are critical to engine sealing and compression—worn or damaged rings lead to blow-by, oil consumption, and power loss. The PROX Ring Set 02.1213 delivers OEM-quality replacement rings...PX4260R- SKU:
- PX4260R
- Availability:
- Ships Same Business Day
- Weight:
- 0.38 LBS
- PRODUCT NAME:
- PISTON RING
- UNITS:
- SET
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
$24.95Qty in Cart: 0Quantity:Price:$24.95Subtotal: -
PROX Piston Kit 01.4108.B
PROX
$89.95A worn or damaged piston compromises combustion efficiency, reduces power output, and risks catastrophic engine failure. The PROX Piston Kit 01.4108.B delivers OEM-equivalent performance with...PX4280B- SKU:
- PX4280B
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- PISTON DIAMETER METRIC:
- 47.95 MM
- RIDING STYLE:
- OFF-ROAD
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD SIZE B
- UNITS:
- EACH
- BORE SIZE METRIC:
- 47.95 MM
- PRODUCT NAME:
- PISTON KIT
$89.95Qty in Cart: 0Quantity:Price:$89.95Subtotal: -
PROX Ring Set 02.4100
PROX
$24.95Piston rings are the critical seal between your combustion chamber and crankcase—when they wear, compression drops, blow-by increases, and power output suffers. The PROX Ring Set 02.4100 delivers...PX4290R- SKU:
- PX4290R
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- PRODUCT NAME:
- PISTON RING
- RIDING STYLE:
- OFF-ROAD
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- SET
$24.95Qty in Cart: 0Quantity:Price:$24.95Subtotal: -
PROX Piston Kit 01.4213.C
PROX
$105.95Stock pistons wear out, and when they do, your engine's compression, power delivery, and reliability suffer. The PROX Piston Kit 01.4213.C delivers OEM-equivalent performance with Japanese...PX4294C- SKU:
- PX4294C
- Availability:
- Ships Same Business Day
- Weight:
- 0.38 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD SIZE C
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- BORE SIZE METRIC:
- 53.96 MM
- PISTON DIAMETER METRIC:
- 53.96 MM
- PRODUCT NAME:
- PISTON KIT
$105.95Qty in Cart: 0Quantity:Price:$105.95Subtotal: -
PROX Ring Set 02.4305
PROX
$39.95Piston rings are critical to engine sealing and compression integrity—worn or substandard rings lead to blow-by, lost power, and accelerated wear on cylinder walls. The PROX Ring Set 02.4305 delivers...PX4305R- SKU:
- PX4305R
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- PRODUCT NAME:
- PISTON RING
- RIDING STYLE:
- OFF-ROAD
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- SET
$39.95Qty in Cart: 0Quantity:Price:$39.95Subtotal:
