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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HOT RODS Crankshaft Kit CBK0124
HOT RODS
$768.95If you're building a high-performance engine or refreshing a tired crankshaft, the HOT RODS Crankshaft Kit CBK0124 delivers factory-matched reliability with performance that meets or exceeds OEM specifications. This complete assembly arrives...09210358- SKU:
- 09210358
- Availability:
- Ships Same Business Day
- Weight:
- 13.08 LBS
- TYPE:
- OEM
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- CRANKSHAFT KIT
- UNITS:
- KIT
$768.95 -
HOT RODS Crankshaft 4068
HOT RODS
$150.95If you're building a long-stroke engine for your ATV, you need a crankshaft engineered specifically for the application—not a compromised OEM unit that limits potential. The HOT RODS Crankshaft 4068 arrives factory-assembled, trued to OEM tolerances, and...09210076- SKU:
- 09210076
- Availability:
- Ships Same Business Day
- Weight:
- 4.78 LBS
- COLOR/FINISH:
- STEEL
- DISPLACEMENT:
- 85 CC
- MATERIAL:
- 4140 STEEL
- RIDING STYLE:
- OFF-ROAD
- STROKE LENGTH METRIC:
- 48.00 MM
- UNITS:
- ASSEMBLY
- MODEL:
- 2-CYCLE
- FEATURES:
- STANDARD CRANKSHAFT
- TYPE:
- OEM STROKE
- PRODUCT NAME:
- CRANKSHAFT ASSEMBLY
$150.95 -
HOT RODS Crankshaft - Stroker 4166
HOT RODS
$316.95A stroker crankshaft transforms your ATV's engine into a powerhouse by increasing displacement and torque output without sacrificing reliability. The HOT RODS 4166 eliminates the machine work and custom fabrication typically required for long-stroke...09210077- SKU:
- 09210077
- Availability:
- Ships Same Business Day
- Weight:
- 4.60 LBS
- COLOR/FINISH:
- STEEL
- DISPLACEMENT:
- 88 CC TO 103.5 CC
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- ASSEMBLY
- MATERIAL:
- 4140 STEEL
- MODEL:
- 2-CYCLE
- PRODUCT NAME:
- CRANKSHAFT ASSEMBLY
- STROKE LENGTH:
- 47,80 MM
- STROKE LENGTH METRIC:
- 47.80 MM
- FEATURES:
- STANDARD CRANKSHAFT
- TYPE:
- STROKER
$316.95 -
On Sale
COMETIC Clutch Cover Gasket - Kawasaki EC513018AFM
COMETIC
MSRP: $13.95Now: $12.56Was: $13.95A failing clutch cover gasket compromises engine sealing and can lead to oil weeping, contamination, and catastrophic drivetrain failure. The COMETIC Clutch Cover Gasket (EC513018AFM) is engineered to OE specifications and trusted by professional racers...09345456- SKU:
- 09345456
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- PRODUCT NAME:
- GASKET
- UNITS:
- SET
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH COVER
MSRP: $13.95Now: $12.56Was: $13.95Qty in Cart: 0Quantity:Price:MSRP: $13.95Now: $12.56Was: $13.95Subtotal: -
On Sale
COMETIC Top End Gasket Set - Yamaha C3105
COMETIC
MSRP: $41.95Now: $37.76Was: $41.95A factory gasket set won't cut it when you're running high boost or aggressive naturally aspirated power levels—combustion pressure and heat cycles will compromise the seal and kill your horsepower gains. The COMETIC C3105 top end gasket set uses...09343427- SKU:
- 09343427
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- TOP END
- RIDING STYLE:
- OFF-ROAD
MSRP: $41.95Now: $37.76Was: $41.95 -
Hot Cams Stage 1 Camshaft for Yamaha TTR125E 2003-2009 4019-1
HOT CAMS
$252.95If you're running a TTR125E in competitive or high-performance riding conditions, factory cam timing limits your acceleration and throttle responsiveness. The Hot Cams Stage 1 transforms low-end power delivery with optimized valve lift and duration,...TTR125S1A- SKU:
- TTR125S1A
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- APPLICATION:
- INTAKE
- INTAKE DURATION IMPERIAL:
- 227°
- INTAKE LIFT METRIC:
- 6.80 MM
- APPLICATION:
- EXHAUST
- PRODUCT NAME:
- CAMSHAFT
- EXHAUST DURATION IMPERIAL:
- 223°
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- STAGE 1
- UNITS:
- EACH
- EXHAUST LIFT METRIC:
- 5.90 MM
$252.95Qty in Cart: 0Quantity:Price:$252.95Subtotal: -
Hot Cams Stage 1 Camshaft for Honda CRF100F 2004-2013 1018-1
HOT CAMS
$244.95If you're running a CRF100F and want measurable gains in low-end torque without sacrificing reliability, the Hot Cams Stage 1 Camshaft is a straightforward bolt-on upgrade that delivers real power across the RPM band. This cam is engineered to work...XR100S1A- SKU:
- XR100S1A
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- EXHAUST LIFT METRIC:
- 5.90 MM
- TYPE:
- STAGE 1
- APPLICATION:
- EXHAUST
- INTAKE DURATION IMPERIAL:
- 236°
- INTAKE LIFT METRIC:
- 6.80 MM
- PRODUCT NAME:
- CAMSHAFT
- APPLICATION:
- INTAKE
- EXHAUST DURATION IMPERIAL:
- 216°
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$244.95 -
Hot Cams Stage 1 Camshaft for 1996-2004 Honda XR250R 1006-1
HOT CAMS
$377.95The Hot Cams Stage 1 Camshaft transforms your XR250R's powerband by optimizing valve timing for responsive low-end torque—ideal if you're looking for improved throttle feel without major engine work. This bolt-on upgrade leverages advanced ITR technology...XR250S1A- SKU:
- XR250S1A
- Availability:
- Ships Same Business Day
- Weight:
- 1.16 LBS
- INTAKE LIFT METRIC:
- 9.00 MM
- APPLICATION:
- INTAKE
- EXHAUST DURATION IMPERIAL:
- 236°
- TYPE:
- STAGE 1
- UNITS:
- EACH
- APPLICATION:
- EXHAUST
- EXHAUST LIFT METRIC:
- 8.70 MM
- INTAKE DURATION IMPERIAL:
- 236°
- PRODUCT NAME:
- CAMSHAFT
- RIDING STYLE:
- OFF-ROAD
$377.95 -
Hot Cams Stage 1 Camshaft for 1988-2000 Honda XR600R 1993-2009 Honda XR650L 1004-1
HOT CAMS
$311.95If you're running an XR600R or XR650L and want measurable gains in low-end pull and mid-range response, the Hot Cams Stage 1 is a straightforward bolt-on upgrade that delivers real-world performance without requiring valve spring replacement. This...XR600S1A- SKU:
- XR600S1A
- Availability:
- Ships Same Business Day
- Weight:
- 1.25 LBS
- INTAKE DURATION IMPERIAL:
- 258°
- RIDING STYLE:
- OFF-ROAD
- APPLICATION:
- INTAKE
- EXHAUST DURATION IMPERIAL:
- 258°
- UNITS:
- EACH
- INTAKE LIFT METRIC:
- 8.80 MM
- PRODUCT NAME:
- CAMSHAFT
- APPLICATION:
- EXHAUST
- EXHAUST LIFT METRIC:
- 8.80 MM
- TYPE:
- STAGE 1
$311.95 -
Hot Cams Stage 2 Intake Camshaft for 2011-2016 Kawasaki KX250F 2220-2IN
HOT CAMS
$294.95If you're serious about extracting maximum performance from your KX250F, camshaft selection is where gains are made. The Hot Cams Stage 2 Intake Camshaft delivers measurable improvements in peak horsepower and high-RPM power delivery—critical for...09250663- SKU:
- 09250663
- Availability:
- Ships Same Business Day
- Weight:
- 0.83 LBS
- PRODUCT NAME:
- CAMSHAFT
- APPLICATION:
- INTAKE
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- INTAKE DURATION IMPERIAL:
- 245°
- INTAKE LIFT METRIC:
- 9.65 MM
- TYPE:
- STAGE 2
$294.95Qty in Cart: 0Quantity:Price:$294.95Subtotal: -
Hot Cams Stage 1 Camshaft for 2009 Honda CRF450R 1123-1
HOT CAMS
$403.95If you're running a 2009 Honda CRF450R and looking to unlock more usable torque without sacrificing reliability, the Hot Cams Stage 1 is the most straightforward bolt-on upgrade available. This drop-in camshaft transforms mid-range power delivery while...09250459- SKU:
- 09250459
- Availability:
- Ships Same Business Day
- Weight:
- 1.25 LBS
- INTAKE DURATION IMPERIAL:
- 235°
- APPLICATION:
- EXHAUST
- INTAKE LIFT METRIC:
- 9.60 MM
- PRODUCT NAME:
- CAMSHAFT
- TYPE:
- STAGE 1
- UNITS:
- EACH
- APPLICATION:
- INTAKE
- EXHAUST DURATION IMPERIAL:
- 248°
- EXHAUST LIFT METRIC:
- 8.70 MM
- RIDING STYLE:
- OFF-ROAD
$403.95Qty in Cart: 0Quantity:Price:$403.95Subtotal: -
Hot Cams Cam Chain Honda TRX700XX 2008-2009 HC92RH2010120
HOT CAMS
$50.95The cam chain is critical to your TRX700XX's valve timing and engine reliability—any wear or slack directly impacts performance and can lead to costly engine damage. HOT CAMS' heat-treated silent chain delivers superior durability and reduced noise...09251169- SKU:
- 09251169
- Availability:
- Ships Same Business Day
- Weight:
- 0.41 LBS
- BASE FINISH:
- RAW
- RIDING STYLE:
- STREET
- COLOR/FINISH:
- RAW
- MATERIAL:
- STEEL
- MODEL:
- SILENT
- CHAIN SIZE:
- 92RH2010
- PRODUCT NAME:
- CHAIN
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CAM
- UNITS:
- EACH
$50.95 -
Hot Cams Stage 1 Intake Camshaft for 2017-2019 Kawasaki KX250F 2311-1IN
HOT CAMS
$264.95The stock camshaft in your KX250F limits what your engine can truly deliver. Hot Cams Stage 1 intake cam unlocks mid-range torque and throttle response that transforms acceleration without requiring valve spring upgrades. If you're serious about track...09251242- SKU:
- 09251242
- Availability:
- Ships Same Business Day
- Weight:
- 0.86 LBS
- PRODUCT NAME:
- CAMSHAFT
- TYPE:
- STAGE 1
- RIDING STYLE:
- OFF-ROAD
- APPLICATION:
- INTAKE
- INTAKE DURATION IMPERIAL:
- 242°
- INTAKE LIFT METRIC:
- 9.90 MM
- UNITS:
- EACH
$264.95 -
Hot Cams Valve Shim 9.48mm x 2.55mm for Honda CRF450R 2002-2009 5PK948255
HOT CAMS
$10.95Valve clearance directly impacts engine efficiency, combustion timing, and overall reliability—even small deviations can reduce power output or cause premature wear. The HOT CAMS Valve Shim 5-pack gives you precision adjustments to dial in optimal...09261399- SKU:
- 09261399
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- VALVE
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 2.55 MM
- RIDING STYLE:
- ATV
- RIDING STYLE:
- STREET
- MATERIAL:
- STEEL
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- OFF-ROAD
$10.95 -
Hot Cams Valve Shim 9.48mm x 2.85mm 5PK948285
HOT CAMS
$10.95Valve clearance directly impacts combustion efficiency, engine longevity, and overall performance—and these Hot Cams shims let you dial in exact specifications without guesswork. Whether you're rebuilding a top end, fine-tuning a race engine, or...09261405- SKU:
- 09261405
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
- MATERIAL:
- STEEL
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- SNOW
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- STREET
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 2.85 MM
$10.95 -
On Sale
PROX Piston Kit 01.1408.150
PROX
MSRP: $185.95Now: $158.00Was: $185.95When your engine demands reliability under extreme conditions, OEM-spec pistons are non-negotiable. The PROX Piston Kit 01.1408.150 delivers factory-matched performance with the precision engineering required for consistent power delivery and longevity...09030820- SKU:
- 09030820
- Availability:
- Ships Same Business Day
- Weight:
- 1.34 LBS
- PISTON SIZE METRIC:
- +1.50 MM
- BORE SIZE METRIC:
- 90.50 MM
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- EACH
- PRODUCT NAME:
- PISTON KIT
MSRP: $185.95Now: $158.00Was: $185.95 -
VERTEX Piston Kit - Standard 22991A
VERTEX
$171.95Piston durability and engine longevity depend on materials that withstand extreme combustion pressures and thermal cycling. The VERTEX Piston Kit 22991A combines proprietary heat treatment with a specialized skirt coating that reduces friction during...09100984- SKU:
- 09100984
- Availability:
- Ships Same Business Day
- Weight:
- 0.31 LBS
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- CAST
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- DISPLACEMENT:
- 105 CC
- PISTON DIAMETER METRIC:
- 51.95 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- COMPRESSION RATIO IMPERIAL:
- STANDARD
- CYLINDER DIAMETER METRIC:
- 52.00 MM
- STYLE:
- CAST REPLICA
$171.95 -
VERTEX Piston Kit 22532B
VERTEX
$197.95A quality piston kit is fundamental to engine reliability and performance—especially under high-load conditions where inferior materials fail. The VERTEX Piston Kit 22532B delivers the durability and precision you need for consistent power delivery,...09100987- SKU:
- 09100987
- Availability:
- Ships Same Business Day
- Weight:
- 0.35 LBS
- PISTON DIAMETER METRIC:
- 54.20 MM
- PRODUCT NAME:
- PISTON KIT
- COMPRESSION RATIO IMPERIAL:
- STANDARD
- CYLINDER DIAMETER METRIC:
- 54.25 MM
- PISTON MATERIAL:
- CAST
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- DISPLACEMENT:
- 125 CC
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- STYLE:
- CAST REPLICA
$197.95Qty in Cart: 0Quantity:Price:$197.95Subtotal: -
VERTEX Piston Kit - Standard 23383A
VERTEX
$217.95VERTEX pistons are engineered for consistent power delivery and extended engine life, making them the choice for builders who demand reliability under sustained high RPM operation. The T-5 heat treatment process ensures superior hardness and dimensional...09100990- SKU:
- 09100990
- Availability:
- Ships Same Business Day
- Weight:
- 0.44 LBS
- COMPRESSION RATIO IMPERIAL:
- STANDARD
- STYLE:
- CAST REPLICA
- PISTON DIAMETER METRIC:
- 55.95 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- CYLINDER DIAMETER METRIC:
- 56.00 MM
- DISPLACEMENT:
- 144 CC
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- CAST
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$217.95Qty in Cart: 0Quantity:Price:$217.95Subtotal: -
Wiseco Piston Kit Standard 77mm 13.5:1 Kawasaki KX250F 2011-2014 40019M07700
WISECO
$224.95When your KX250F's stock piston reaches its limit, a quality replacement isn't optional—it's essential for maintaining power delivery and engine longevity. The Wiseco 40019M07700 delivers the compression ratio and durability expected in modern 4-stroke...09102895- SKU:
- 09102895
- Availability:
- Ships Same Business Day
- Weight:
- 0.54 LBS
- BORE - OVERSIZE:
- STANDARD
- RIDING STYLE:
- OFF-ROAD
- BORE - OVERSIZE METRIC:
- STANDARD
- BORE SIZE METRIC:
- 77.00 MM
- COMPRESSION RATIO IMPERIAL:
- 13.5:1
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- PRODUCT NAME:
- PISTON
- STROKE LENGTH METRIC:
- 53.60 MM
- UNITS:
- EACH
- DISPLACEMENT:
- 250 CC
$224.95Qty in Cart: 0Quantity:Price:$224.95Subtotal:
