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 Top End Gasket Set - Honda 35.1334
PROX
$84.95PROX Top End Gasket Set - Honda09345672- SKU:
- 09345672
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- UNITS:
- SET
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- GASKET SET
- TYPE:
- TOP END
$84.95 -
PROX Top End Gasket Set - Honda 35.1402
PROX
$89.95PROX Top End Gasket Set - Honda09345677- SKU:
- 09345677
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- PRODUCT NAME:
- GASKET SET
- UNITS:
- SET
$89.95 -
PROX Top End Gasket Set - Honda 35.1409
PROX
$39.95PROX Top End Gasket Set - Honda09345681- SKU:
- 09345681
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- GASKET SET
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- SET
$39.95Qty in Cart: 0Quantity:Price:$39.95Subtotal: -
PROX Top End Gasket Set - Yamaha 35.2113
PROX
$19.95PROX Top End Gasket Set - Yamaha09345685- SKU:
- 09345685
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- UNITS:
- SET
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- GASKET SET
- TYPE:
- TOP END
$19.95 -
PROX Top End Gasket Set - Yamaha 35.2122
PROX
$24.95PROX Top End Gasket Set - Yamaha09345686- SKU:
- 09345686
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- GASKET SET
- TYPE:
- TOP END
- UNITS:
- SET
$24.95 -
PROX Top End Gasket Set - Yamaha 35.2201
PROX
$49.95PROX Top End Gasket Set - Yamaha09345687- SKU:
- 09345687
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- TYPE:
- TOP END
- PRODUCT NAME:
- GASKET SET
- UNITS:
- SET
- RIDING STYLE:
- OFF-ROAD
$49.95 -
PROX Piston Kit 01.2215.B
PROX
$105.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...PX7214B- SKU:
- PX7214B
- Availability:
- Ships Same Business Day
- Weight:
- 0.44 LBS
- BORE SIZE METRIC:
- 53.95 MM
- ENGINE TYPE:
- 2-STROKE
- PISTON SIZE METRIC:
- +0.01 MM
- PISTON DIAMETER METRIC:
- 53.95 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- PRODUCT NAME:
- PISTON KIT
$105.95 -
PROX Piston Kit 01.4223.A
PROX
$101.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...09100024- SKU:
- 09100024
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- PISTON DIAMETER METRIC:
- 53.95 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- PISTON SIZE METRIC:
- STANDARD SIZE A
- BORE SIZE METRIC:
- 53.95 MM
- ENGINE TYPE:
- 2-STROKE
- RIDING STYLE:
- OFF-ROAD
$101.95 -
PROX Piston Kit 01.1414.A
PROX
$195.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...09100607- SKU:
- 09100607
- Availability:
- Ships Same Business Day
- Weight:
- 0.81 LBS
- BORE SIZE METRIC:
- 95.96 MM
- PISTON DIAMETER METRIC:
- 95.96 MM
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- PISTON SIZE METRIC:
- STANDARD SIZE A
- RIDING STYLE:
- OFF-ROAD
$195.95 -
PROX Piston Kit 01.1338.B
PROX
$185.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...09101127- SKU:
- 09101127
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- PISTON DIAMETER METRIC:
- 77.98 MM
- BORE SIZE METRIC:
- 77.98 MM
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
$185.95 -
PROX Connecting Rod 03.6520
PROX
$199.95Comes complete with crankpin, big-end bearing, small-end bearing, and washers, Easy to install09230138- SKU:
- 09230138
- Availability:
- Ships Same Business Day
- Weight:
- 1.92 LBS
- MATERIAL:
- FORGED STEEL
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- CONNECTING ROD KIT
- ENGINE TYPE:
- 4-STROKE
- RIDING STYLE:
- ATV
- UNITS:
- EACH
$199.95 -
PROX Connecting Rod 03.4285
PROX
$119.95Comes complete with crankpin, big-end bearing, small-end bearing, and washers, Easy to install09230161- SKU:
- 09230161
- Availability:
- Ships Same Business Day
- Weight:
- 0.76 LBS
- MATERIAL:
- FORGED STEEL
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$119.95 -
PROX Exhaust Valve 28.1356-1
PROX
$29.95Manufactured to the highest precision and quality, Constructed to meet OEM specifications, Available in standard sizes only09260673- SKU:
- 09260673
- Availability:
- Ships Same Business Day
- Weight:
- 0.08 LBS
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- APPLICATION:
- EXHAUST
- PRODUCT NAME:
- VALVE
$29.95 -
PROX Intake Valve 28.1356-2
PROX
$19.95Manufactured to the highest precision and quality, Constructed to meet OEM specifications, Available in standard sizes only09260674- SKU:
- 09260674
- Availability:
- Ships Same Business Day
- Weight:
- 0.09 LBS
- APPLICATION:
- INTAKE
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- VALVE
- UNITS:
- EACH
$19.95 -
PROX Connecting Rod 03.3402
PROX
$175.95Comes complete with crankpin, big-end bearing, small-end bearing, and washers, Easy to install09230164- SKU:
- 09230164
- Availability:
- Ships Same Business Day
- Weight:
- 1.68 LBS
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- UNITS:
- EACH
- ENGINE TYPE:
- 4-STROKE
- MATERIAL:
- FORGED STEEL
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
$175.95 -
PROX Connecting Rod 03.6323
PROX
$119.95Comes complete with crankpin, big-end bearing, small-end bearing, and washers, Easy to install09230173- SKU:
- 09230173
- Availability:
- Ships Same Business Day
- Weight:
- 0.99 LBS
- ENGINE TYPE:
- 2-STROKE
- MATERIAL:
- FORGED STEEL
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- STREET
- UNITS:
- EACH
$119.95Qty in Cart: 0Quantity:Price:$119.95Subtotal: -
PROX Connecting Rod 03.3323
PROX
$119.95Comes complete with crankpin, big-end bearing, small-end bearing, and washers, Easy to install09230185- SKU:
- 09230185
- Availability:
- Ships Same Business Day
- Weight:
- 1.02 LBS
- UNITS:
- EACH
- ENGINE TYPE:
- 2-STROKE
- MATERIAL:
- FORGED STEEL
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
$119.95 -
PROX Crank Bearing and Seal Kit 23.CBS13092
PROX
$65.95Made to exact OEM specifications for maximum performance and durability, Includes all necessary bearings/seals for a component's replacement, For use with OEM or Pro X crankshafts09240302- SKU:
- 09240302
- Availability:
- Ships Same Business Day
- Weight:
- 1.60 LBS
- PRODUCT NAME:
- BEARING AND SEAL KIT
- STYLE:
- 2-STROKE
- APPLICATION:
- CRANKSHAFT
- TYPE:
- BALL
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$65.95 -
PROX Crank Bearing and Seal Kit 23.CBS14006
PROX
$109.95Made to exact OEM specifications for maximum performance and durability, Includes all necessary bearings/seals for a component's replacement, For use with OEM or Pro X crankshafts09240305- SKU:
- 09240305
- Availability:
- Ships Same Business Day
- Weight:
- 1.40 LBS
- APPLICATION:
- CRANKSHAFT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- BEARING AND SEAL KIT
- STYLE:
- 4-STROKE
- TYPE:
- BALL
$109.95 -
PROX Top End Gasket Set - Yamaha 35.2423
PROX
$64.95PROX Top End Gasket Set - Yamaha09345710- SKU:
- 09345710
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- PRODUCT NAME:
- GASKET SET
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- SET
$64.95
