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 03.1654
PROX
$199.95A connecting rod is the critical link between your piston and crankshaft—any flex, wear, or imbalance directly undermines engine efficiency and reliability. The PROX 03.1654 is a complete,...09230179- SKU:
- 09230179
- Availability:
- Ships Same Business Day
- Weight:
- 2.35 LBS
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- FEATURES:
- INCLUDES THRUST WASHERS
- MATERIAL:
- FORGED STEEL
- UNITS:
- EACH
$199.95Qty in Cart: 0Quantity:Price:$199.95Subtotal: -
PROX Connecting Rod 03.6319
PROX
$132.95A connecting rod is the critical link between your piston and crankshaft—it must withstand extreme pressures, rapid acceleration, and sustained RPMs without failure. The PROX 03.6319 is engineered to...09230180- SKU:
- 09230180
- Availability:
- Ships Same Business Day
- Weight:
- 0.98 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 03.6017
PROX
$118.95A connecting rod is the critical link between your crankshaft and piston, transmitting combustion forces while managing extreme temperatures and RPM cycles. The PROX 03.6017 is a complete assembly...09230182- SKU:
- 09230182
- Availability:
- Ships Same Business Day
- Weight:
- 0.63 LBS
- MATERIAL:
- FORGED STEEL
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- ENGINE TYPE:
- 2-STROKE
- UNITS:
- EACH
$118.95 -
PROX Connecting Rod 03.2304
PROX
$132.95A connecting rod is the critical link between your crankshaft and piston—any weakness here translates directly to power loss and catastrophic failure under high RPM loads. The PROX 03.2304 is...09230186- SKU:
- 09230186
- Availability:
- Ships Same Business Day
- Weight:
- 1.04 LBS
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- ENGINE TYPE:
- 2-STROKE
- MATERIAL:
- FORGED STEEL
- PRODUCT NAME:
- CONNECTING ROD KIT
$132.95 -
PROX Connecting Rod 03.1495
PROX
$177.95A connecting rod is the critical link between your crankshaft and piston—it must handle extreme forces while maintaining precise tolerances. The PROX 03.1495 is engineered for reliability and...09230187- SKU:
- 09230187
- Availability:
- Ships Same Business Day
- Weight:
- 1.67 LBS
- UNITS:
- EACH
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- ENGINE TYPE:
- 4-STROKE
- MATERIAL:
- FORGED STEEL
$177.95 -
PROX Connecting Rod 03.4406
PROX
$175.95A connecting rod is the critical link between your crankshaft and piston, transmitting combustion forces while managing reciprocating loads at extreme RPMs. The PROX 03.4406 arrives fully assembled...09230189- SKU:
- 09230189
- Availability:
- Ships Same Business Day
- Weight:
- 1.60 LBS
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- MATERIAL:
- FORGED STEEL
$175.95 -
PROX Connecting Rod 03.2007
PROX
$87.95A connecting rod is the critical link between your crankshaft and piston—it must withstand extreme pressures and temperatures while maintaining precise tolerances. The PROX Connecting Rod 03.2007 is...09230193- SKU:
- 09230193
- Availability:
- Ships Same Business Day
- Weight:
- 0.55 LBS
- ENGINE TYPE:
- 2-STROKE
- MATERIAL:
- FORGED STEEL
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$87.95 -
PROX Connecting Rod Kit - Yamaha YZ 250 F 03.2414
PROX
$173.95A connecting rod is the critical link between your piston and crankshaft—any wear, damage, or imbalance here directly compromises engine reliability and performance. The PROX Connecting Rod Kit for...09230365- SKU:
- 09230365
- Availability:
- Ships Same Business Day
- Weight:
- 1.20 LBS
- MATERIAL:
- FORGED
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- CONNECTING ROD KIT
$173.95 -
PROX Connecting Rod 03.1090
PROX
$55.95A connecting rod is the critical link between your crankshaft and piston—any flex, wear, or weakness here directly compromises engine reliability and power delivery. The PROX 03.1090 is a...09230344- SKU:
- 09230344
- Availability:
- Ships Same Business Day
- Weight:
- 0.45 LBS
- FEATURES:
- INCLUDES THRUST WASHERS
- MATERIAL:
- FORGED STEEL
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- CONNECTING ROD KIT
$55.95Qty in Cart: 0Quantity:Price:$55.95Subtotal: -
PROX Connecting Rod 03.1409
PROX
$183.95A connecting rod is the critical link between your crankshaft and piston, and it needs to handle extreme forces without flex or failure. The PROX Connecting Rod 03.1409 delivers precision engineering...09230345- SKU:
- 09230345
- Availability:
- Ships Same Business Day
- Weight:
- 1.59 LBS
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- FEATURES:
- INCLUDES THRUST WASHERS
- MATERIAL:
- FORGED STEEL
- ENGINE TYPE:
- 4-STROKE
$183.95 -
PROX Connecting Rod Kit - Beta RR250/300/X-Trainer 03.7313
PROX
$129.95A connecting rod is the critical link between your piston and crankshaft—any wear or failure here means catastrophic engine damage. The PROX Connecting Rod Kit for Beta RR250/300/X-Trainer models...09230352- SKU:
- 09230352
- Availability:
- Ships Same Business Day
- Weight:
- 1.00 LBS
- ENGINE TYPE:
- 2-STROKE
- MATERIAL:
- FORGED
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- MATERIAL:
- STEEL
- PRODUCT NAME:
- CONNECTING ROD KIT
$129.95 -
PROX Connecting Rod 03.4342
PROX
$165.95A connecting rod is the critical link between your crankshaft and piston—it converts linear motion into rotational power, and any weakness here compromises engine reliability and performance. The...09230322- SKU:
- 09230322
- Availability:
- Ships Same Business Day
- Weight:
- 1.20 LBS
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- MATERIAL:
- FORGED STEEL
$165.95Qty in Cart: 0Quantity:Price:$165.95Subtotal: -
PROX Connecting Rod Kit - Honda XR200R/XL125K 03.1255
PROX
$116.95The connecting rod is the critical link between your piston and crankshaft—any wear, bend, or failure here will sideline your bike. PROX's complete kit eliminates the guesswork by supplying all...09230294- SKU:
- 09230294
- Availability:
- Ships Same Business Day
- Weight:
- 1.40 LBS
- UNITS:
- KIT
- MATERIAL:
- STEEL
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- ENGINE TYPE:
- 4-STROKE
- MATERIAL:
- FORGED
$116.95 -
PROX Piston Kit 01.1342.C
PROX
$185.95When your engine demands precision and reliability, factory-original performance isn't negotiable. The PROX Piston Kit 01.1342.C delivers OEM-equivalent durability through meticulous Japanese...09030815- SKU:
- 09030815
- Availability:
- Ships Same Business Day
- Weight:
- 0.52 LBS
- RIDING STYLE:
- OFF-ROAD
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- BORE SIZE METRIC:
- 76.80 MM
- COMPRESSION RATIO IMPERIAL:
- 13.2:1
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- PISTON KIT
- TYPE:
- TOP END
- PISTON SIZE METRIC:
- STANDARD SIZE A
$185.95Qty in Cart: 0Quantity:Price:$185.95Subtotal: -
PROX Piston Kit 01.1342.B
PROX
$185.95Worn or damaged pistons compromise combustion efficiency, reduce power output, and risk catastrophic engine failure. The PROX Piston Kit 01.1342.B delivers OEM-equivalent performance with precision...09030816- SKU:
- 09030816
- Availability:
- Ships Same Business Day
- Weight:
- 0.51 LBS
- PISTON SIZE METRIC:
- STANDARD SIZE B
- PRODUCT NAME:
- PISTON KIT
- TYPE:
- TOP END
- COMPRESSION RATIO IMPERIAL:
- 13.2:1
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 76.80 MM
$185.95Qty in Cart: 0Quantity:Price:$185.95Subtotal: -
PROX Piston Kit 01.1414.C
PROX
$195.95A worn or damaged piston kit will compromise engine efficiency, increase blow-by, and risk catastrophic engine failure. The PROX Piston Kit 01.1414.C delivers OEM-grade replacement performance with...09030819- SKU:
- 09030819
- Availability:
- Ships Same Business Day
- Weight:
- 0.88 LBS
- BORE SIZE METRIC:
- 96.00 MM
- PRODUCT NAME:
- PISTON KIT
- COMPRESSION RATIO IMPERIAL:
- 12.0:1
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD SIZE C
- UNITS:
- EACH
- ENGINE TYPE:
- 4-STROKE
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
$195.95Qty in Cart: 0Quantity:Price:$195.95Subtotal: -
PROX Piston Kit 01.1411.B
PROX
$195.95When your engine's pistons are worn or damaged, you're losing compression, efficiency, and power—and risking catastrophic failure. The PROX Piston Kit 01.1411.B delivers OEM-equivalent performance...09030823- SKU:
- 09030823
- Availability:
- Ships Same Business Day
- Weight:
- 0.79 LBS
- ENGINE TYPE:
- 4-STROKE
- PISTON SIZE METRIC:
- STANDARD SIZE B
- PRODUCT NAME:
- PISTON KIT
- TYPE:
- TOP END
- BORE SIZE METRIC:
- 95.97 MM
- RIDING STYLE:
- OFF-ROAD
- COMPRESSION RATIO IMPERIAL:
- 12.0:1
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
$195.95Qty in Cart: 0Quantity:Price:$195.95Subtotal: -
PROX Piston Kit 01.2114.C
PROX
$99.95When your engine's pistons wear beyond safe operating limits, you're facing compromised compression, oil blow-by, and potential catastrophic failure. The PROX Piston Kit 01.2114.C delivers...09030828- SKU:
- 09030828
- Availability:
- Ships Same Business Day
- Weight:
- 0.32 LBS
- BORE SIZE METRIC:
- 47.50 MM
- PISTON SIZE METRIC:
- STANDARD SIZE C
- PRODUCT NAME:
- PISTON KIT
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- EACH
$99.95 -
PROX Piston Kit 01.2429.C
PROX
$195.95Your engine's heart demands precision engineering and materials that can withstand extreme combustion pressures cycle after cycle. The PROX Piston Kit 01.2429.C delivers exactly that—OEM-equivalent...09030829- SKU:
- 09030829
- Availability:
- Ships Same Business Day
- Weight:
- 0.88 LBS
- COMPRESSION RATIO IMPERIAL:
- 12.5:1
- PRODUCT NAME:
- PISTON KIT
- BORE SIZE METRIC:
- 95.00 MM
- PISTON SIZE METRIC:
- STANDARD SIZE C
- RIDING STYLE:
- OFF-ROAD
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- TYPE:
- TOP END
- UNITS:
- EACH
$195.95 -
PROX Piston Kit 01.4121.C
PROX
$89.95A piston kit is the heart of engine reliability and performance—worn or damaged pistons directly compromise compression, power delivery, and engine longevity. The PROX Piston Kit 01.4121.C delivers...09030830- SKU:
- 09030830
- Availability:
- Ships Same Business Day
- Weight:
- 0.33 LBS
- BORE SIZE METRIC:
- 48.50 MM
- RIDING STYLE:
- OFF-ROAD
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD SIZE C
- UNITS:
- EACH
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- PISTON KIT
- TYPE:
- TOP END
$89.95Qty in Cart: 0Quantity:Price:$89.95Subtotal:
