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 03.3211
PROX
$132.95A connecting rod is the critical link between your piston and crankshaft—any weakness here directly compromises power delivery and engine reliability. The PROX 03.3211 is a complete, ready-to-install assembly that eliminates the guesswork of sourcing...09230178- SKU:
- 09230178
- Availability:
- Ships Same Business Day
- Weight:
- 0.73 LBS
- ENGINE TYPE:
- 2-STROKE
- MATERIAL:
- FORGED STEEL
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- CONNECTING ROD KIT
- UNITS:
- EACH
$132.95 -
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 deliver the reliability and precision you need,...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 designed to deliver reliable performance in high-demand...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 engineered for durability in demanding racing and...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 performance, delivering the durability demanded by both...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 with all bearing components, eliminating the guesswork...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 engineered to deliver reliable power transfer and...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 Yamaha YZ 250 F delivers OEM-equivalent precision with...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 03.1409
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 with a complete assembly that eliminates the need to...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 delivers OEM-equivalent quality with precision-machined...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 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 necessary components in one package, ensuring proper bearing...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 01.2114.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 OEM-equivalent performance with the precision engineering of...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 performance with the reliability of a...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 -
On Sale
PROX Piston Kit 01.1323.A
PROX
MSRP: $143.95Now: $119.00Was: $143.95When your engine's pistons show signs of wear or damage, replacement isn't optional—it's essential for maintaining compression, preventing catastrophic failure, and preserving your engine's performance envelope. The PROX Piston Kit 01.1323.A delivers...PX1322A- SKU:
- PX1322A
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- PRODUCT NAME:
- PISTON KIT
- PISTON DIAMETER METRIC:
- 66.34 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- BORE SIZE METRIC:
- 66.34 MM
- ENGINE TYPE:
- 2-STROKE
- PISTON SIZE METRIC:
- STANDARD SIZE A
- RIDING STYLE:
- OFF-ROAD
MSRP: $143.95Now: $119.00Was: $143.95 -
On Sale
PROX Piston Kit 01.2114.A
PROX
MSRP: $99.95Now: $76.00Was: $99.95Worn or damaged pistons compromise compression, reliability, and power output—making a quality replacement essential for any engine rebuild or high-mileage refresh. The PROX Piston Kit 01.2114.A delivers OEM-matched performance with the precision...PX2112A- SKU:
- PX2112A
- Availability:
- Ships Same Business Day
- Weight:
- 0.32 LBS
- RIDING STYLE:
- OFF-ROAD
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- BORE SIZE METRIC:
- 47.44 MM
- ENGINE TYPE:
- 2-STROKE
- PISTON DIAMETER METRIC:
- 47.44 MM
- PRODUCT NAME:
- PISTON KIT
- PISTON SIZE METRIC:
- STANDARD SIZE A
MSRP: $99.95Now: $76.00Was: $99.95 -
On Sale
PROX Piston Kit 01.2114.B
PROX
MSRP: $99.95Now: $76.00Was: $99.95Piston failure compromises engine reliability and performance—whether you're rebuilding after catastrophic wear or upgrading to factory-plus specifications. The PROX Piston Kit 01.2114.B delivers OEM-equivalent durability with precision engineering,...PX2112B- SKU:
- PX2112B
- Availability:
- Ships Same Business Day
- Weight:
- 0.32 LBS
- ENGINE TYPE:
- 2-STROKE
- PISTON DIAMETER METRIC:
- 47.45 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD SIZE B
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- BORE SIZE METRIC:
- 47.45 MM
- RIDING STYLE:
- OFF-ROAD
MSRP: $99.95Now: $76.00Was: $99.95 -
On Sale
PROX Piston Kit 01.2224.A
PROX
MSRP: $121.95Now: $90.00Was: $121.95When your engine's stock pistons reach the end of their service life, you need a direct replacement that matches OEM specifications without compromise. The PROX Piston Kit 01.2224.A delivers the precision engineering and material quality required for...PX2222A- SKU:
- PX2222A
- Availability:
- Ships Same Business Day
- Weight:
- 0.32 LBS
- PISTON DIAMETER METRIC:
- 53.94 MM
- RIDING STYLE:
- OFF-ROAD
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- BORE SIZE METRIC:
- 53.94 MM
- PISTON SIZE METRIC:
- STANDARD SIZE A
- PRODUCT NAME:
- PISTON KIT
MSRP: $121.95Now: $90.00Was: $121.95 -
On Sale
PROX Piston Kit 01.2224.B
PROX
MSRP: $121.95Now: $90.00Was: $121.95When your engine demands reliability and precision, OEM-quality pistons are non-negotiable. The PROX Piston Kit 01.2224.B delivers factory-spec performance without factory downtime, engineered in Japan to exact tolerances that keep your engine running at...PX2222B- SKU:
- PX2222B
- Availability:
- Ships Same Business Day
- Weight:
- 0.32 LBS
- BORE SIZE METRIC:
- 53.95 MM
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD SIZE B
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- PISTON DIAMETER METRIC:
- 53.95 MM
- PRODUCT NAME:
- PISTON KIT
MSRP: $121.95Now: $90.00Was: $121.95 -
On Sale
PROX Piston Kit 01.1408.000
PROX
MSRP: $185.95Now: $158.00Was: $185.95A worn or damaged piston kit compromises combustion efficiency, increases blow-by, and can lead to catastrophic engine failure. The PROX Piston Kit 01.1408.000 restores your engine to OEM performance specifications with precision-engineered components...PX4040- SKU:
- PX4040
- Availability:
- Ships Same Business Day
- Weight:
- 1.25 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD
- UNITS:
- EACH
- ENGINE TYPE:
- 2-STROKE
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 89.00 MM
- PISTON DIAMETER METRIC:
- 89.00 MM
- PRODUCT NAME:
- PISTON KIT
MSRP: $185.95Now: $158.00Was: $185.95 -
On Sale
PROX Piston Kit 01.1408.050
PROX
MSRP: $185.95Now: $158.00Was: $185.95A piston kit is fundamental to engine reliability and performance—worn or damaged pistons compromise compression, increase blow-by, and accelerate engine wear. The PROX Piston Kit 01.1408.050 delivers OEM-equivalent engineering with Japanese...PX4042- SKU:
- PX4042
- Availability:
- Ships Same Business Day
- Weight:
- 1.26 LBS
- BORE SIZE METRIC:
- 89.50 MM
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- PISTON SIZE METRIC:
- +0.50 MM
- RIDING STYLE:
- OFF-ROAD
- PISTON DIAMETER METRIC:
- 89.50 MM
MSRP: $185.95Now: $158.00Was: $185.95
