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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On Sale
KIBBLEWHITE Exhaust Valve Guide 30-30740
KIBBLEWHITE
MSRP: $15.92Now: $14.33Was: $15.92Valve guides are critical components that direct oil flow and maintain precise valve alignment under extreme combustion pressures. The KIBBLEWHITE 30-30740 exhaust valve guide uses Ampco-45, a...09300021- SKU:
- 09300021
- Availability:
- Ships Same Business Day
- Weight:
- 0.03 LBS
- INSIDE DIAMETER IMPERIAL:
- 0.2150'
- APPLICATION:
- EXHAUST
- OUTSIDE DIAMETER IMPERIAL:
- 0.4360'
- MATERIAL:
- AMPCO-45
- PRODUCT NAME:
- VALVE GUIDE
- RIDING STYLE:
- ATV
- UNITS:
- EACH
MSRP: $15.92Now: $14.33Was: $15.92 -
K&S TECHNOLOGIES Water Pump Repair Gasket Kit - YZF450 75-4003
K&S TECHNOLOGIES
$38.95A failing water pump gasket kit can quickly escalate into catastrophic engine damage—coolant leaks compromise thermal management and leave you stranded trackside or roadside. The K&S Technologies...09341923- SKU:
- 09341923
- Availability:
- Ships Same Business Day
- Weight:
- 0.22 LBS
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- ATV
- TYPE:
- WATER PUMP REPAIR
- UNITS:
- KIT
$38.95 -
On Sale
JAMES GASKET Alternator Cap Cover O-ring ST-11900029
JAMES GASKET
MSRP: $6.95Now: $4.00Was: $6.95Alternator cap cover o-rings are critical sealing components that prevent moisture, dirt, and debris from compromising your alternator's internal windings and electrical connections. A deteriorated...09351073- SKU:
- 09351073
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- APPLICATION:
- ALTERNATOR CAP
- PRODUCT NAME:
- O-RING
- RIDING STYLE:
- STREET
- UNITS:
- 5 PACK
MSRP: $6.95Now: $4.00Was: $6.95 -
On Sale
JAMES GASKET Clutch Actuator Shaft O-ring ST-11900030
JAMES GASKET
MSRP: $3.95Now: $3.00Was: $3.95A worn or degraded clutch actuator shaft o-ring compromises hydraulic pressure and leads to inconsistent clutch engagement—a critical issue for reliable operation. This genuine JAMES GASKET...09351074- SKU:
- 09351074
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- APPLICATION:
- CLUTCH
- PRODUCT NAME:
- O-RING
- RIDING STYLE:
- STREET
- UNITS:
- 5 PACK
MSRP: $3.95Now: $3.00Was: $3.95Qty in Cart: 0Quantity:Price:MSRP: $3.95Now: $3.00Was: $3.95Subtotal: -
On Sale
JAMES GASKET Thermostat O-Ring 10969
JAMES GASKET
Now: $4.00Was: $6.20A failing thermostat o-ring is one of the easiest ways to develop coolant leaks that go undetected until serious engine damage occurs. The JAMES GASKET Thermostat O-Ring 10969 is a...09351087- SKU:
- 09351087
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- TYPE:
- THERMOSTAT
- PRODUCT NAME:
- O-RING
- RIDING STYLE:
- STREET
- UNITS:
- 5 PACK
Now: $4.00Was: $6.20 -
On Sale
JAMES GASKET Cylinder Head Gasket ST-16500085
JAMES GASKET
MSRP: $97.95Now: $63.00Was: $97.95A quality cylinder head gasket is critical to maintaining combustion sealing and preventing costly coolant or oil leaks. The JAMES GASKET ST-16500085 is a genuine OEM-equivalent kit engineered to...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
MSRP: $97.95Now: $63.00Was: $97.95 -
On Sale
JAMES GASKET Cam Chain Tensioner Gasket ST-25500005
JAMES GASKET
MSRP: $48.95Now: $31.00Was: $48.95A failing cam chain tensioner gasket will compromise your engine's internal sealing integrity and lead to costly oil leakage and potential timing chain wear. The JAMES GASKET ST-25500005 delivers 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
MSRP: $48.95Now: $31.00Was: $48.95 -
On Sale
JAMES GASKET Water Pump Body Seal ST-26600017
JAMES GASKET
MSRP: $7.95Now: $5.00Was: $7.95A failing water pump seal is a silent engine killer—coolant leaks can lead to catastrophic overheating and thermal damage that sidelines your build or race season. The JAMES GASKET Water Pump Body...09351085- SKU:
- 09351085
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- TYPE:
- WATER PUMP BODY
- RIDING STYLE:
- STREET
- PRODUCT NAME:
- SEAL
- UNITS:
- KIT
MSRP: $7.95Now: $5.00Was: $7.95Qty in Cart: 0Quantity:Price:MSRP: $7.95Now: $5.00Was: $7.95Subtotal: -
On Sale
JAMES GASKET Complete Motor Gasket Kit ST-25700443
JAMES GASKET
MSRP: $217.95Now: $139.00Was: $217.95A complete engine rebuild demands precision sealing across every critical junction—oil passages, combustion chambers, and bearing surfaces. This JAMES GASKET kit delivers OEM-quality gaskets, oil...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
MSRP: $217.95Now: $139.00Was: $217.95 -
On Sale
JAMES GASKET Breather Baffle Gasket ST-29400074
JAMES GASKET
MSRP: $40.95Now: $26.00Was: $40.95A properly functioning breather system is critical to engine longevity and performance—excessive crankcase pressure leads to seal failure, oil leaks, and reduced reliability. The JAMES GASKET...09346485- SKU:
- 09346485
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- PRODUCT NAME:
- GASKET
- TYPE:
- BREATHER
- UNITS:
- 2 PACK
- RIDING STYLE:
- STREET
MSRP: $40.95Now: $26.00Was: $40.95 -
On Sale
JAMES GASKET Valve Cover - Grommet ST-6114-15
JAMES GASKET
MSRP: $19.95Now: $13.00Was: $19.95A properly sealed valve cover is critical to preventing oil leakage and maintaining clean engine bay conditions. The JAMES GASKET Valve Cover Grommet ST-6114-15 delivers reliable, long-lasting...09346486- SKU:
- 09346486
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- PRODUCT NAME:
- GROMMET
- RIDING STYLE:
- STREET
- TYPE:
- VALVE COVER
- UNITS:
- 10 PACK
MSRP: $19.95Now: $13.00Was: $19.95 -
JE PISTONS Piston Kit 345192
JE PISTONS
$839.99When you're pushing your engine to the limits in professional competition, your pistons need to handle extreme pressures and temperatures without compromise. JE PISTONS 345192 kits are engineered...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
$309.99When you're pushing your engine to its absolute limit in professional competition, your pistons need to match that intensity. JE PISTONS' Pro Series 208552 kit delivers the precision engineering and...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
$309.99Qty in Cart: 0Quantity:Price:$309.99Subtotal: -
JE PISTONS Piston Kit 128996
JE PISTONS
$269.99When you're pushing an engine to its absolute limit, stock pistons simply won't cut it. JE PISTONS' Pro Series 128996 kit is engineered specifically for professional competition and extreme...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
$269.99If you're pushing your engine to the limit in competition or high-performance applications, your pistons need to match that commitment. JE PISTONS' Pro Series 128998 kit delivers the precision...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
$269.99When you're pushing your engine to the absolute limit in professional competition, your pistons need to handle extreme loads without compromise. JE PISTONS 130682 kits deliver the precision...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
$269.99When you're pushing an engine to its absolute limit in competition, your pistons need to match that intensity. JE's Pro Series kit delivers the precision engineering and durability required 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
$269.99Qty in Cart: 0Quantity:Price:$269.99Subtotal: -
JE PISTONS Piston Kit 133889
JE PISTONS
$269.99When you're pushing your engine to the limit in competition, your pistons need to withstand extreme pressures and temperatures without compromise. JE Pistons' Pro Series kit delivers the precision...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
$269.99Qty in Cart: 0Quantity:Price:$269.99Subtotal: -
JE PISTONS Piston Kit 177239
JE PISTONS
$269.99When you're pushing your engine to the limit in competition, every component needs to withstand extreme pressure and maintain precision under stress. JE Pistons' 177239 kit delivers the durability...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
$269.99Qty in Cart: 0Quantity:Price:$269.99Subtotal: -
JE PISTONS Piston Kit 177240
JE PISTONS
$269.99When you're pushing your engine to the absolute limit in competition, your pistons need to survive extreme cylinder pressures and sustained high RPM without compromise. JE Pistons' Pro Series 177240...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
$269.99Qty in Cart: 0Quantity:Price:$269.99Subtotal:
