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
-
KIBBLEWHITE Exhaust Valve Guide 30-30740
KIBBLEWHITE
$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 specialized copper-nickel alloy engineered specifically for...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
$15.92 -
K&S TECHNOLOGIES Water Pump Repair Gasket Kit - YZF450 75-4003
K&S TECHNOLOGIES
$34.95A 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 Water Pump Repair Gasket Kit delivers OEM-quality sealing...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
$34.95 -
JAMES GASKET Alternator Cap Cover O-ring ST-11900029
JAMES GASKET
$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 or missing o-ring can lead to corrosion, voltage...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
$6.95 -
JAMES GASKET Clutch Actuator Shaft O-ring ST-11900030
JAMES GASKET
$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 replacement restores proper sealing, ensuring crisp clutch feel...09351074- SKU:
- 09351074
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- APPLICATION:
- CLUTCH
- PRODUCT NAME:
- O-RING
- RIDING STYLE:
- STREET
- UNITS:
- 5 PACK
$3.95 -
JAMES GASKET Thermostat O-Ring 10969
JAMES GASKET
$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 precision-engineered replacement that restores a reliable seal at the...09351087- SKU:
- 09351087
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- TYPE:
- THERMOSTAT
- PRODUCT NAME:
- O-RING
- RIDING STYLE:
- STREET
- UNITS:
- 5 PACK
$6.20 -
JAMES GASKET Cylinder Head Gasket ST-16500085
JAMES GASKET
$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 factory specifications, ensuring reliable performance...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 Cam Chain Tensioner Gasket ST-25500005
JAMES GASKET
$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 reliable, factory-quality replacement that restores...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
$7.95A 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 Seal ST-26600017 delivers reliable, long-lasting sealing...09351085- SKU:
- 09351085
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- TYPE:
- WATER PUMP BODY
- RIDING STYLE:
- STREET
- PRODUCT NAME:
- SEAL
- UNITS:
- KIT
$7.95Qty in Cart: 0Quantity:Price:$7.95Subtotal: -
JAMES GASKET Complete Motor Gasket Kit ST-25700443
JAMES GASKET
$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 seals, and o-rings in one package, eliminating the...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
$40.95A 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 Breather Baffle Gasket ST-29400074 ensures a tight, dependable...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
$19.95A 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 sealing performance with precision engineering and domestic...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
$839.99When 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 specifically for forced induction and high-boost...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 structural reinforcement required for extreme...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
$269.99When 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 applications, delivering the reliability and precision you need...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 engineering and durability required for extreme racing...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 engineering and material science required for forced induction...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 extreme applications where failure isn't an option. Built...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 engineering and materials that separate winners from the...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 and performance you demand with forged 2618-T6 aluminum...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 kit delivers the precision engineering and material...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:
