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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JAMES GASKET Thermostat O-Ring 10969
JAMES GASKET
$5.50JAMES GASKET Thermostat O-Ring09351087- SKU:
- 09351087
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- TYPE:
- THERMOSTAT
- PRODUCT NAME:
- O-RING
- RIDING STYLE:
- STREET
- UNITS:
- 5 PACK
$5.50 -
JAMES GASKET Cylinder Head Gasket ST-16500085
JAMES GASKET
$97.95Genuine James kits include matching head and base gaskets and O-rings where applicable, Made in the U.S.A.09346474- SKU:
- 09346474
- Availability:
- Ships Same Business Day
- Weight:
- 0.35 LBS
- MATERIAL:
- -
- RIDING STYLE:
- STREET
- THICKNESS IMPERIAL:
- 0,045'
- BORE SIZE:
- STANDARD
- BORE SIZE IMPERIAL:
- STANDARD
- TYPE:
- CYLINDER HEAD
- PRODUCT NAME:
- GASKET
- THICKNESS METRIC:
- 1.14 MM
- UNITS:
- 2 PACK
$97.95 -
JAMES GASKET Cylinder Head Gasket ST-16500123
JAMES GASKET
$97.95Genuine James kits include matching head and base gaskets and O-rings where applicable, Made in the U.S.A.09346476- SKU:
- 09346476
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- RIDING STYLE:
- STREET
- MATERIAL:
- -
- THICKNESS IMPERIAL:
- 0,045'
- BORE SIZE:
- STANDARD
- PRODUCT NAME:
- GASKET
- THICKNESS METRIC:
- 1.14 MM
- TYPE:
- CYLINDER HEAD
- BORE SIZE IMPERIAL:
- STANDARD
- UNITS:
- 2 PACK
$97.95Qty in Cart: 0Quantity:Price:$97.95Subtotal: -
JAMES GASKET Cam Chain Tensioner Gasket ST-25500005
JAMES GASKET
$48.95Foamet feature an aluminum core coated on two sides with expanded nitrile rubber, then coated with a silicone release coating to ensure a positive seal with excellent release characteristic upon disassembly., Made in the U.S.A.09346478- SKU:
- 09346478
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- UNITS:
- 2 PACK
- TYPE:
- CAM CHAIN TENSIONER
- PRODUCT NAME:
- GASKET
- RIDING STYLE:
- STREET
$48.95 -
JAMES GASKET Water Pump Body Seal ST-26600017
JAMES GASKET
$7.95JAMES GASKET Water Pump Body Seal09351085- SKU:
- 09351085
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- TYPE:
- WATER PUMP BODY
- RIDING STYLE:
- STREET
- PRODUCT NAME:
- SEAL
- UNITS:
- KIT
$7.95 -
JAMES GASKET Complete Motor Gasket Kit ST-25700443
JAMES GASKET
$217.95To-quality gaskets, oil seals, and o-rings necessary to rebuild an engine, Made in the U.S.A.09346483- SKU:
- 09346483
- Availability:
- Ships Same Business Day
- Weight:
- 1.15 LBS
- BORE SIZE METRIC:
- 69.00 MM
- UNITS:
- KIT
- BORE SIZE:
- 69,00 MM
- RIDING STYLE:
- STREET
- THICKNESS IMPERIAL:
- 0.045'
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- ENGINE
$217.95 -
JAMES GASKET Breather Baffle Gasket ST-29400074
JAMES GASKET
$40.95Made in the U.S.A.09346485- SKU:
- 09346485
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- PRODUCT NAME:
- GASKET
- TYPE:
- BREATHER
- UNITS:
- 2 PACK
- RIDING STYLE:
- STREET
$40.95 -
JAMES GASKET Valve Cover - Grommet ST-6114-15
JAMES GASKET
$19.95Made in the U.S.A.09346486- SKU:
- 09346486
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- PRODUCT NAME:
- GROMMET
- RIDING STYLE:
- STREET
- TYPE:
- VALVE COVER
- UNITS:
- 10 PACK
$19.95 -
JE PISTONS Piston Kit 345192
JE PISTONS
$839.99Machined from 2618-T6 high-tensile forged aluminum, Dome/dish features smooth flowing radii; requires no deburring or preparation, Specifically engineered for extreme applications including professional competition, Pro Series pistons available for...09105946- SKU:
- 09105946
- Availability:
- Ships Same Business Day
- Weight:
- 2.91 LBS
- BORE SIZE METRIC:
- 80.00 MM
- PRODUCT NAME:
- PISTON KIT
- WALL THICKNESS:
- 0,160'
- DISPLACEMENT:
- 998 CC
- UNITS:
- KIT
- COMPRESSION RATIO IMPERIAL:
- 9.5:1
- PISTON HEAD SHAPE:
- DISHED
- RIDING STYLE:
- UTV
- WALL THICKNESS IMPERIAL:
- 0.160'
$839.99 -
JE PISTONS Piston Kit 208552
JE PISTONS
$309.99Machined from 2618-T6 high-tensile forged aluminum, Dome/dish features smooth flowing radii; requires no deburring or preparation, Specifically engineered for extreme applications including professional competition, Pro Series pistons available for...09105830- SKU:
- 09105830
- Availability:
- Ships Same Business Day
- Weight:
- 1.35 LBS
- BORE SIZE METRIC:
- 89.00 MM
- DISPLACEMENT:
- 435 CC
- PRODUCT NAME:
- PISTON KIT
- WALL THICKNESS IMPERIAL:
- 0.180'
- WALL THICKNESS:
- 0,180'
- COMPRESSION RATIO IMPERIAL:
- 12.0:1
- PISTON HEAD SHAPE:
- DOMED
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$309.99 -
JE PISTONS Piston Kit 128996
JE PISTONS
$269.99Machined from 2618-T6 high-tensile forged aluminum, Dome/dish features smooth flowing radii; requires no deburring or preparation, Specifically engineered for extreme applications including professional competition, Pro Series pistons available for...09105832- SKU:
- 09105832
- Availability:
- Ships Same Business Day
- Weight:
- 1.50 LBS
- BORE - OVERSIZE:
- +4,00 MM
- PISTON HEAD SHAPE:
- FLAT TOP
- BORE - OVERSIZE METRIC:
- +4.00 MM
- BORE SIZE METRIC:
- 101.00 MM
- COMPRESSION RATIO IMPERIAL:
- 10.6:1
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- ROUND FORGED DESIGN
- UNITS:
- KIT
- DISPLACEMENT:
- 640 CC
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- PRODUCT NAME:
- PISTON KIT
- STYLE:
- JE PISTON
$269.99 -
JE PISTONS Piston Kit 128998
JE PISTONS
$269.99Machined from 2618-T6 high-tensile forged aluminum, Dome/dish features smooth flowing radii; requires no deburring or preparation, Specifically engineered for extreme applications including professional competition, Pro Series pistons available for...09105833- SKU:
- 09105833
- Availability:
- Ships Same Business Day
- Weight:
- 1.55 LBS
- BORE - OVERSIZE:
- +5,00 MM
- BORE SIZE METRIC:
- 102.00 MM
- PRODUCT NAME:
- PISTON KIT
- DISPLACEMENT:
- 654 CC
- PISTON HEAD SHAPE:
- FLAT TOP
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- STYLE:
- JE PISTON
- COMPRESSION RATIO IMPERIAL:
- 10.8:1
- TYPE:
- ROUND FORGED DESIGN
- UNITS:
- KIT
- BORE - OVERSIZE METRIC:
- +5.00 MM
- RIDING STYLE:
- OFF-ROAD
$269.99 -
JE PISTONS Piston Kit 130682
JE PISTONS
$269.99Machined from 2618-T6 high-tensile forged aluminum, Dome/dish features smooth flowing radii; requires no deburring or preparation, Specifically engineered for extreme applications including professional competition, Pro Series pistons available for...09105834- SKU:
- 09105834
- Availability:
- Ships Same Business Day
- Weight:
- 1.61 LBS
- PISTON HEAD SHAPE:
- FLAT TOP
- TYPE:
- ROUND FORGED DESIGN
- BORE SIZE METRIC:
- 100.00 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BORE - OVERSIZE:
- STANDARD
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- PRODUCT NAME:
- PISTON KIT
- STYLE:
- JE PISTON
- BORE - OVERSIZE METRIC:
- STANDARD
- COMPRESSION RATIO IMPERIAL:
- 11.25:1
- DISPLACEMENT:
- 644 CC
$269.99 -
JE PISTONS Piston Kit 131243
JE PISTONS
$269.99Machined from 2618-T6 high-tensile forged aluminum, Dome/dish features smooth flowing radii; requires no deburring or preparation, Specifically engineered for extreme applications including professional competition, Pro Series pistons available for...09105836- SKU:
- 09105836
- Availability:
- Ships Same Business Day
- Weight:
- 0.96 LBS
- COMPRESSION RATIO IMPERIAL:
- 10.5:1
- PISTON HEAD SHAPE:
- DOMED
- STYLE:
- JE PISTON
- TYPE:
- ROUND FORGED DESIGN
- UNITS:
- KIT
- DISPLACEMENT:
- 277 CC
- BORE - OVERSIZE:
- +4,00 MM
- BORE SIZE METRIC:
- 77.00 MM
- BORE - OVERSIZE METRIC:
- +4.00 MM
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- STREET
$269.99 -
JE PISTONS Piston Kit 133889
JE PISTONS
$269.99Machined from 2618-T6 high-tensile forged aluminum, Dome/dish features smooth flowing radii; requires no deburring or preparation, Specifically engineered for extreme applications including professional competition, Pro Series pistons available for...09105838- SKU:
- 09105838
- Availability:
- Ships Same Business Day
- Weight:
- 1.21 LBS
- BORE - OVERSIZE METRIC:
- +2.00 MM
- BORE SIZE METRIC:
- 87.00 MM
- DISPLACEMENT:
- 415 CC
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- JE PISTON
- UNITS:
- KIT
- BORE - OVERSIZE:
- +2,00 MM
- COMPRESSION RATIO IMPERIAL:
- 10.8:1
- PISTON HEAD SHAPE:
- DOMED
- TYPE:
- ROUND FORGED DESIGN
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- PRODUCT NAME:
- PISTON KIT
$269.99 -
JE PISTONS Piston Kit 177239
JE PISTONS
$269.99Machined from 2618-T6 high-tensile forged aluminum, Dome/dish features smooth flowing radii; requires no deburring or preparation, Specifically engineered for extreme applications including professional competition, Pro Series pistons available for...09105840- SKU:
- 09105840
- Availability:
- Ships Same Business Day
- Weight:
- 1.16 LBS
- BORE - OVERSIZE:
- +3,00 MM
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- JE PISTON
- UNITS:
- KIT
- DISPLACEMENT:
- 426 CC
- PISTON HEAD SHAPE:
- DOMED
- TYPE:
- ROUND FORGED DESIGN
- BORE - OVERSIZE METRIC:
- +3.00 MM
- BORE SIZE METRIC:
- 88.00 MM
- COMPRESSION RATIO IMPERIAL:
- 13.0:1
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- PRODUCT NAME:
- PISTON KIT
$269.99 -
JE PISTONS Piston Kit 177240
JE PISTONS
$269.99Machined from 2618-T6 high-tensile forged aluminum, Dome/dish features smooth flowing radii; requires no deburring or preparation, Specifically engineered for extreme applications including professional competition, Pro Series pistons available for...09105841- SKU:
- 09105841
- Availability:
- Ships Same Business Day
- Weight:
- 1.21 LBS
- BORE - OVERSIZE:
- +3,00 MM
- COMPRESSION RATIO IMPERIAL:
- 11.0:1
- RIDING STYLE:
- OFF-ROAD
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- STYLE:
- JE PISTON
- DISPLACEMENT:
- 426 CC
- PISTON HEAD SHAPE:
- DOMED
- TYPE:
- ROUND FORGED DESIGN
- UNITS:
- KIT
- BORE - OVERSIZE METRIC:
- +3.00 MM
- BORE SIZE METRIC:
- 88.00 MM
- PRODUCT NAME:
- PISTON KIT
$269.99 -
JE PISTONS Piston Kit 180297
JE PISTONS
$269.99Machined from 2618-T6 high-tensile forged aluminum, Dome/dish features smooth flowing radii; requires no deburring or preparation, Specifically engineered for extreme applications including professional competition, Pro Series pistons available for...09105842- SKU:
- 09105842
- Availability:
- Ships Same Business Day
- Weight:
- 1.16 LBS
- BORE - OVERSIZE:
- STANDARD
- DISPLACEMENT:
- 398 CC
- RIDING STYLE:
- ATV
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- STYLE:
- JE PISTON
- BORE - OVERSIZE METRIC:
- STANDARD
- COMPRESSION RATIO IMPERIAL:
- 12.0:1
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- ROUND FORGED DESIGN
- UNITS:
- KIT
- BORE SIZE METRIC:
- 90.00 MM
- PISTON HEAD SHAPE:
- DISHED
- PRODUCT NAME:
- PISTON KIT
$269.99 -
JE PISTONS Piston Kit 183051
JE PISTONS
$269.99Machined from 2618-T6 high-tensile forged aluminum, Dome/dish features smooth flowing radii; requires no deburring or preparation, Specifically engineered for extreme applications including professional competition, Pro Series pistons available for...09105843- SKU:
- 09105843
- Availability:
- Ships Same Business Day
- Weight:
- 1.41 LBS
- BORE SIZE METRIC:
- 94.00 MM
- COMPRESSION RATIO IMPERIAL:
- 12.0:1
- RIDING STYLE:
- ATV
- BORE - OVERSIZE METRIC:
- +4.00 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- PRODUCT NAME:
- PISTON KIT
- STYLE:
- JE PISTON
- BORE - OVERSIZE:
- +4,00 MM
- DISPLACEMENT:
- 434 CC
- PISTON HEAD SHAPE:
- DISHED
- TYPE:
- ROUND FORGED DESIGN
$269.99 -
JE PISTONS Piston Kit 209283
JE PISTONS
$309.99Machined from 2618-T6 high-tensile forged aluminum, Dome/dish features smooth flowing radii; requires no deburring or preparation, Specifically engineered for extreme applications including professional competition, Pro Series pistons available for...09105844- SKU:
- 09105844
- Availability:
- Ships Same Business Day
- Weight:
- 1.41 LBS
- WALL THICKNESS:
- 0,150'
- BORE SIZE METRIC:
- 100.00 MM
- DISPLACEMENT:
- 651 CC
- UNITS:
- KIT
- COMPRESSION RATIO IMPERIAL:
- 11.5:1
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- ATV
- PISTON HEAD SHAPE:
- DOMED
- WALL THICKNESS IMPERIAL:
- 0.150'
$309.99
