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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Rekluse Clutch Cover Kawasaki KX450F 2016-2018 RMS-444
REKLUSE
$179.00The stock clutch cover on your KX450F limits oil capacity and leaves your drivetrain vulnerable to trail impacts. The Rekluse RMS-444 replaces that weakness with a billet aluminum design that holds more oil for superior cooling and lubrication, while its...09401829- SKU:
- 09401829
- Availability:
- Ships Same Business Day
- Weight:
- 0.96 LBS
- COLOR/FINISH:
- BLACK
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- TYPE:
- CLUTCH
- COLOR/FINISH:
- ANODIZED
- MATERIAL:
- BILLET ALUMINUM
- PRODUCT NAME:
- COVER
$179.00 -
REKLUSE Clutch Cover Kawasaki KX450 2021 RMS-445
REKLUSE
$229.00Off-road riding demands clutch protection that can handle repeated impacts without compromising lubrication or performance. The REKLUSE Clutch Cover for your KX450 delivers the durability you need with a robust billet aluminum construction and increased...09401830- SKU:
- 09401830
- Availability:
- Ships Same Business Day
- Weight:
- 0.95 LBS
- RIDING STYLE:
- STREET
- PRODUCT NAME:
- COVER
- RIDING STYLE:
- ATV
- UNITS:
- EACH
- COLOR/FINISH:
- ANODIZED
- COLOR/FINISH:
- BLACK
- MATERIAL:
- BILLET ALUMINUM
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
$229.00 -
Rekluse Clutch Cover for Suzuki RM-Z450 2008-2025 RMS-464
REKLUSE
$229.00Stock clutch covers are vulnerable to trail damage and limited oil capacity—a liability when you're pushing hard on technical terrain. The Rekluse RMS-464 replaces that weakness with a billet aluminum cover engineered to absorb impacts while maintaining...09401831- SKU:
- 09401831
- Availability:
- Ships Same Business Day
- Weight:
- 1.00 LBS
- TYPE:
- CLUTCH
- COLOR/FINISH:
- BLACK
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- COLOR/FINISH:
- ANODIZED
- MATERIAL:
- BILLET ALUMINUM
- PRODUCT NAME:
- COVER
$229.00 -
Rekluse Clutch Cover Yamaha YZ250 1999-2025 RMS-470
REKLUSE
$229.00The stock YZ250 clutch cover leaves your bike vulnerable to trail damage and thermal stress. Rekluse's billet aluminum replacement fortifies your engine case with impact-resistant protection while increasing oil capacity for better cooling during...09401833- SKU:
- 09401833
- Availability:
- Ships Same Business Day
- Weight:
- 0.95 LBS
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- COLOR/FINISH:
- ANODIZED
- COLOR/FINISH:
- BLACK
- MATERIAL:
- BILLET ALUMINUM
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
$229.00 -
Rekluse Clutch Cover Yamaha YZ450F 2010-2021 WR450F 2016-2021 YZ450FX 2016-2021 RMS-476
REKLUSE
$229.00If you're running a YZ450F, WR450F, or YZ450FX hard, your clutch cover needs to handle sustained heat, pressure, and trail abuse without compromising engine lubrication. The Rekluse clutch cover increases oil capacity beyond OEM specs, ensuring...09401836- SKU:
- 09401836
- Availability:
- Ships Same Business Day
- Weight:
- 0.95 LBS
- RIDING STYLE:
- STREET
- COLOR/FINISH:
- BLACK
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- TYPE:
- CLUTCH
- COLOR/FINISH:
- ANODIZED
- MATERIAL:
- BILLET ALUMINUM
- PRODUCT NAME:
- COVER
$229.00 -
Rekluse Clutch Cover Kawasaki KX250 2021-2024 RMS-0404140
REKLUSE
$229.00The stock KX250 clutch cover is vulnerable to impact damage and thermal stress during aggressive riding. Rekluse's billet aluminum cover replaces the OEM unit with a reinforced design that withstands rock strikes and boot catches while delivering greater...09401998- SKU:
- 09401998
- Availability:
- Ships Same Business Day
- Weight:
- 0.81 LBS
- COLOR/FINISH:
- ANODIZED
- COLOR/FINISH:
- BLACK
- MATERIAL:
- BILLET ALUMINUM
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
$229.00 -
VERTEX Piston Kit - High Compression 24113A
VERTEX
$367.95If you're building an engine that demands reliability under extreme combustion pressures, the VERTEX Piston Kit 24113A delivers the metallurgical precision required for sustained high-RPM performance. The T-5 heat treatment and molybdenum disulfide skirt...09104119- SKU:
- 09104119
- Availability:
- Ships Same Business Day
- Weight:
- 0.90 LBS
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- FORGED HIGH COMPRESSION
- UNITS:
- KIT
- DISPLACEMENT:
- 450 CC
- COMPRESSION RATIO IMPERIAL:
- 13.3:1
- ENGINE TYPE:
- 4-STROKE
- PISTON DIAMETER METRIC:
- 94.95 MM
- RIDING STYLE:
- STREET
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- CYLINDER DIAMETER METRIC:
- 95.00 MM
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- PRODUCT NAME:
- PISTON KIT
$367.95 -
VERTEX Piston Kit - High Compression 24113B
VERTEX
$367.95High-compression pistons demand precision engineering to handle extreme combustion pressures and thermal cycling without compromising durability or ring sealing. The VERTEX 24113B kit delivers race-proven construction with advanced surface treatments...09104120- SKU:
- 09104120
- Availability:
- Ships Same Business Day
- Weight:
- 0.60 LBS
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- FORGED HIGH COMPRESSION
- UNITS:
- KIT
- DISPLACEMENT:
- 450 CC
- COMPRESSION RATIO IMPERIAL:
- 13.3:1
- ENGINE TYPE:
- 4-STROKE
- RIDING STYLE:
- STREET
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- CYLINDER DIAMETER METRIC:
- 95.00 MM
- PISTON DIAMETER METRIC:
- 94.96 MM
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- PRODUCT NAME:
- PISTON KIT
$367.95 -
VERTEX Piston Kit 22224B
VERTEX
$148.95A quality piston kit is the foundation of any high-performing engine—it directly impacts combustion efficiency, horsepower delivery, and long-term reliability. The VERTEX Piston Kit 22224B combines precision engineering with proven durability features,...09102116- SKU:
- 09102116
- Availability:
- Ships Same Business Day
- Weight:
- 0.47 LBS
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- STYLE:
- CAST REPLICA
- DISPLACEMENT:
- 125 CC
- COMPRESSION RATIO IMPERIAL:
- STANDARD
- CYLINDER DIAMETER METRIC:
- 54.00 MM
- PISTON DIAMETER METRIC:
- 53.94 MM
- PISTON MATERIAL:
- CAST
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- KIT
$148.95 -
VERTEX Piston Kit 22896B
VERTEX
$302.95Whether you're rebuilding a worn top end or upgrading to forged internals for higher compression and power, the VERTEX Piston Kit 22896B delivers the durability and precision demanded by serious racers and engine builders. Each piston is engineered with...09102120- SKU:
- 09102120
- Availability:
- Ships Same Business Day
- Weight:
- 1.09 LBS
- DISPLACEMENT:
- 450 CC
- PISTON DIAMETER METRIC:
- 94.94 MM
- STYLE:
- FORGED HIGH COMPRESSION
- UNITS:
- KIT
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- OFF-ROAD
- COMPRESSION RATIO IMPERIAL:
- 13.5:1
- CYLINDER DIAMETER METRIC:
- 95.00 MM
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
$302.95 -
VERTEX Piston Kit 23614B
VERTEX
$197.95The VERTEX Piston Kit 23614B delivers the durability and precision required for serious engine rebuilds and high-performance builds. Whether you're running cast or forged variants, each piston is engineered with advanced heat treatment and surface...09104646- SKU:
- 09104646
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- PISTON KIT
- COMPRESSION RATIO IMPERIAL:
- STANDARD
- CYLINDER DIAMETER METRIC:
- 52.50 MM
- DISPLACEMENT:
- 99 CC
- PISTON MATERIAL:
- CAST
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- CAST REPLICA
- UNITS:
- KIT
- PISTON DIAMETER METRIC:
- 52.45 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
$197.95 -
VERTEX Piston Kit 23614C
VERTEX
$170.95A piston kit is the foundation of reliable top-end performance, directly affecting power delivery, engine longevity, and overall durability. The VERTEX Piston Kit 23614C delivers precision-engineered components built to withstand extreme operating...09104647- SKU:
- 09104647
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- PISTON DIAMETER METRIC:
- 52.46 MM
- COMPRESSION RATIO IMPERIAL:
- STANDARD
- DISPLACEMENT:
- 99 CC
- PISTON MATERIAL:
- CAST
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- CAST REPLICA
- UNITS:
- KIT
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- PISTON KIT
- CYLINDER DIAMETER METRIC:
- 52.50 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
$170.95 -
VERTEX Piston Kit with Gaskets VTK23614A
VERTEX
$223.95Whether you're rebuilding a high-mileage engine or upgrading to increased displacement, the VERTEX Piston Kit VTK23614A delivers the durability and performance you need for reliable power delivery. Built with forged 2618 aluminum and precision-engineered...09104648- SKU:
- 09104648
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
- DISPLACEMENT:
- 100 CC
- PISTON DIAMETER METRIC:
- 52.44 MM
- COMPRESSION RATIO IMPERIAL:
- STANDARD
- PISTON MATERIAL:
- CAST
- PRODUCT NAME:
- TOP END PISTON KIT
- STYLE:
- CAST REPLICA
- UNITS:
- KIT
- CYLINDER DIAMETER METRIC:
- 52.50 MM
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
$223.95 -
VERTEX Piston Kit 24233A
VERTEX
$208.95Engine longevity and peak performance depend on piston quality—and VERTEX delivers both with forged and cast options engineered for your specific power goals. Whether you're chasing maximum displacement on a big bore or maximizing compression ratios,...09105753- SKU:
- 09105753
- Availability:
- Ships Same Business Day
- Weight:
- 0.55 LBS
- CYLINDER DIAMETER METRIC:
- 58.00 MM
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- CAST RACE
- COMPRESSION RATIO IMPERIAL:
- STANDARD
- DISPLACEMENT:
- 144 CC
- PISTON MATERIAL:
- CAST
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- UNITS:
- KIT
- PISTON DIAMETER METRIC:
- 57.94 MM
- PRODUCT NAME:
- PISTON KIT
$208.95 -
VERTEX Piston Kit 24233B
VERTEX
$217.95Whether you're rebuilding a two-stroke or refreshing a four-stroke top end, the VERTEX Piston Kit 24233B delivers the durability and precision needed to handle sustained high-RPM operation. Factory-quality construction with premium materials means...09105754- SKU:
- 09105754
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- STYLE:
- CAST RACE
- CYLINDER DIAMETER METRIC:
- 58.00 MM
- PISTON DIAMETER METRIC:
- 57.95 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- PISTON KIT
- COMPRESSION RATIO IMPERIAL:
- STANDARD
- DISPLACEMENT:
- 144 CC
- PISTON MATERIAL:
- CAST
$217.95 -
VERTEX Piston Kit 24187A
VERTEX
$274.95Whether you're rebuilding a tired engine or stepping up compression for serious power gains, the VERTEX Piston Kit 24187A delivers the durability and performance you need to keep running hard. These forged pistons are engineered to handle sustained...09104658- SKU:
- 09104658
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
$274.95 -
VERTEX Piston Kit 24187B
VERTEX
$262.95Whether you're rebuilding a tired engine or upgrading to higher compression ratios, the VERTEX Piston Kit 24187B delivers the strength and reliability that separates quality machine work from corner-cutting. Forged 2618 aluminum construction combined...09104659- SKU:
- 09104659
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
$262.95 -
VERTEX Piston Kit 23928B
VERTEX
$189.95The VERTEX Piston Kit 23928B delivers the durability and precision needed for sustained high-RPM performance, whether you're rebuilding a worn top end or upgrading to higher compression. Built with meticulous heat treatment and advanced surface coatings,...09105156- SKU:
- 09105156
- Availability:
- Ships Same Business Day
- Weight:
- 0.35 LBS
- DISPLACEMENT:
- 125 CC
- PISTON DIAMETER METRIC:
- 53.95 MM
- PRODUCT NAME:
- PISTON KIT
- COMPRESSION RATIO IMPERIAL:
- STANDARD
- CYLINDER DIAMETER METRIC:
- 54.00 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- CAST
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- ENGINE TYPE:
- 2-STROKE
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- CAST REPLICA
- UNITS:
- KIT
$189.95 -
VERTEX Piston Kit 23928C
VERTEX
$176.95Whether you're rebuilding a high-mileage engine or stepping up compression for more power, the VERTEX Piston Kit 23928C delivers the precision and durability you need to make reliable horsepower. These pistons are engineered for consistent performance...09105157- SKU:
- 09105157
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- DISPLACEMENT:
- 125 CC
- COMPRESSION RATIO IMPERIAL:
- STANDARD
- CYLINDER DIAMETER METRIC:
- 54.00 MM
- PISTON DIAMETER METRIC:
- 53.96 MM
- PISTON MATERIAL:
- CAST
- STYLE:
- CAST REPLICA
- UNITS:
- KIT
- PRODUCT NAME:
- PISTON KIT
$176.95 -
VERTEX Piston Kit 24243A
VERTEX
$171.95The VERTEX Piston Kit 24243A delivers the durability and precision your engine demands, whether you're rebuilding a worn-out top end or upgrading for performance. Heat-treated and coated with molybdenum disulfide, these pistons accelerate break-in while...09105159- SKU:
- 09105159
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- STYLE:
- CAST RACE
- DISPLACEMENT:
- 125 CC
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- STREET
- COMPRESSION RATIO IMPERIAL:
- STANDARD
- CYLINDER DIAMETER METRIC:
- 54.00 MM
- PISTON MATERIAL:
- CAST
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PISTON DIAMETER METRIC:
- 53.94 MM
$171.95
