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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Wiseco Piston Kit +1.00 mm Kawasaki KX 80 1991-1997 644M04900
WISECO
$143.95If you're running a Kawasaki KX80 and want to restore lost compression or chase more peak power, a quality piston kit is non-negotiable. The Wiseco 644M04900 delivers the precision fit and material...644M04900- SKU:
- 644M04900
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- BORE - OVERSIZE METRIC:
- +1.00 MM
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- BORE SIZE METRIC:
- 49.00 MM
- DISPLACEMENT:
- 82 CC
- STROKE LENGTH:
- 45,80 MM
- BORE - OVERSIZE:
- +1,00 MM
- RIDING STYLE:
- OFF-ROAD
- STROKE LENGTH METRIC:
- 45.80 MM
- PISTON MATERIAL:
- FORGED
- PRODUCT NAME:
- PISTON
$143.95 -
Wiseco Piston Kit 72mm for 1991-1994 KTM 300 EXC 300 MXC 300 SX 631M07200
WISECO
$244.95If you're running a 1991-1994 KTM 300 EXC, MXC, or SX, a worn or damaged piston directly kills your power delivery and engine reliability. The Wiseco 631M07200 restores your bike to peak performance...631M07200- SKU:
- 631M07200
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- BORE - OVERSIZE METRIC:
- STANDARD
- PISTON MATERIAL:
- FORGED
- PRODUCT NAME:
- PISTON
- STROKE LENGTH METRIC:
- 73.00 MM
- STROKE LENGTH:
- 73,00 MM
- BORE - OVERSIZE:
- STANDARD
- BORE SIZE METRIC:
- 72.00 MM
- DISPLACEMENT:
- 297 CC
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$244.95Qty in Cart: 0Quantity:Price:$244.95Subtotal: -
Wiseco Piston Kit Yamaha YZ 125 2005-2021 56mm 845M05600
WISECO
$154.95Your YZ125's engine demands a piston that can handle the demands of 2-stroke performance—high RPMs, aggressive combustion, and relentless riding conditions. The Wiseco 629M05700 delivers precisely...629M05700- SKU:
- 629M05700
- Availability:
- Ships Same Business Day
- Weight:
- 0.35 LBS
- BORE - OVERSIZE:
- +1,00 MM
- BORE SIZE METRIC:
- 57.00 MM
- DISPLACEMENT:
- 124 CC
- RIDING STYLE:
- OFF-ROAD
- STROKE LENGTH:
- 50,70 MM
- STROKE LENGTH METRIC:
- 50.70 MM
- BORE - OVERSIZE METRIC:
- +1.00 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- UNITS:
- EACH
- PRODUCT NAME:
- PISTON
$154.95Qty in Cart: 0Quantity:Price:$154.95Subtotal: -
Wiseco Piston Standard Yamaha YZ125 2005-2024 629M05600
WISECO
$154.95A worn or damaged piston directly impacts engine reliability, throttle response, and overall performance on the track or trail. The Wiseco 629M05600 restores your YZ125 to factory specifications...629M05600- SKU:
- 629M05600
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- PRODUCT NAME:
- PISTON
- BORE - OVERSIZE METRIC:
- STANDARD
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- UNITS:
- EACH
- BORE - OVERSIZE:
- STANDARD
- BORE SIZE METRIC:
- 56.00 MM
- DISPLACEMENT:
- 124 CC
- RIDING STYLE:
- OFF-ROAD
- STROKE LENGTH:
- 50,70 MM
- STROKE LENGTH METRIC:
- 50.70 MM
$154.95Qty in Cart: 0Quantity:Price:$154.95Subtotal: -
Wiseco Piston 1.50mm Oversize Honda CR250R 2001 614M06800
WISECO
$232.95Worn or damaged pistons rob your CR250R of power and reliability. This Wiseco piston kit restores combustion efficiency and throttle response with precision-engineered construction built to survive...614M06800- SKU:
- 614M06800
- Availability:
- Ships Same Business Day
- Weight:
- 0.90 LBS
- BORE - OVERSIZE METRIC:
- +1.60 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- UNITS:
- EACH
- DISPLACEMENT:
- 249 CC
- STROKE LENGTH:
- 72,00 MM
- BORE SIZE METRIC:
- 68.00 MM
- PRODUCT NAME:
- PISTON
- RIDING STYLE:
- OFF-ROAD
- STROKE LENGTH METRIC:
- 72.00 MM
- BORE - OVERSIZE:
- +1,60 MM
$232.95 -
Wiseco Piston Kit for Yamaha YZ 80 1985-1987 569M04950
WISECO
$144.95If you're running a Yamaha YZ80 and want reliable top-end performance, a quality piston kit is non-negotiable. Wiseco's 569M04950 delivers the precision engineering and durability needed for...569M04950- SKU:
- 569M04950
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- PRODUCT NAME:
- PISTON
- PISTON MATERIAL:
- ALUMINUM ALLOY
- STROKE LENGTH:
- 45,60 MM
- UNITS:
- EACH
- BORE - OVERSIZE:
- +1,50 MM
- BORE SIZE METRIC:
- 49.50 MM
- PISTON MATERIAL:
- FORGED
- RIDING STYLE:
- OFF-ROAD
- BORE - OVERSIZE METRIC:
- +1.50 MM
- DISPLACEMENT:
- 82 CC
- STROKE LENGTH METRIC:
- 45.60 MM
$144.95Qty in Cart: 0Quantity:Price:$144.95Subtotal: -
Wiseco Piston Kit Yamaha YZ 125 2005-2021 1.50mm Oversize 559M05750
WISECO
$179.95If you're running a YZ125 two-stroke, piston wear directly impacts throttle response, fuel efficiency, and overall engine longevity. The Wiseco 559M05750 is engineered to restore lost compression and...559M05750- SKU:
- 559M05750
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- BORE - OVERSIZE:
- +1,50 MM
- BORE SIZE METRIC:
- 57.50 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- UNITS:
- EACH
- DISPLACEMENT:
- 123 CC
- PRODUCT NAME:
- PISTON
- RIDING STYLE:
- OFF-ROAD
- STROKE LENGTH:
- 50,00 MM
- BORE - OVERSIZE METRIC:
- +1.50 MM
- STROKE LENGTH METRIC:
- 50.00 MM
$179.95Qty in Cart: 0Quantity:Price:$179.95Subtotal: -
Wiseco Piston Kit Kawasaki KX 250 1999 617M06640
WISECO
$221.95If you're running a Kawasaki KX250, piston wear is inevitable—and when it hits, your engine's compression, throttle response, and overall reliability take a nosedive. The Wiseco Piston Kit 556M06740...556M06740- SKU:
- 556M06740
- Availability:
- Ships Same Business Day
- Weight:
- 0.75 LBS
- DISPLACEMENT:
- 249 CC
- STROKE LENGTH:
- 70,00 MM
- STROKE LENGTH METRIC:
- 70.00 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- RIDING STYLE:
- ATV
- UNITS:
- EACH
- BORE - OVERSIZE:
- STANDARD
- BORE - OVERSIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 67.40 MM
$221.95 -
Wiseco Piston Kit 85mm 10:1 Compression for Honda TRX400EX 1999-2008 4606M08500
WISECO
$210.95The Honda TRX400EX demands a piston that can handle sustained high-RPM abuse while maintaining reliable power delivery—the Wiseco 4606M08500 delivers exactly that. With a 10:1 compression ratio and...4606M08500- SKU:
- 4606M08500
- Availability:
- Ships Same Business Day
- Weight:
- 0.94 LBS
- BORE - OVERSIZE METRIC:
- STANDARD
- COMPRESSION RATIO IMPERIAL:
- 10.0:1
- DISPLACEMENT:
- 397 CC
- RIDING STYLE:
- OFF-ROAD
- SKIRT COATING:
- NON-COATED
- UNITS:
- KIT
- MODEL:
- FORGED SERIES
- PISTON DIAMETER METRIC:
- 84.95 MM
- BORE - OVERSIZE:
- STANDARD
- ENGINE TYPE:
- 4-STROKE
- RIDING STYLE:
- ATV
- BORE SIZE METRIC:
- 85.00 MM
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- PRODUCT NAME:
- PISTON KIT
- STROKE LENGTH METRIC:
- 70.00 MM
$210.95 -
Wiseco Piston Kit Kawasaki KX250 1978-1986 439M07000
WISECO
$221.95If your KX250 is showing signs of wear or you're looking to restore it to factory specifications, a quality piston kit is essential to maintain compression, seal integrity, and overall engine...439M07000- SKU:
- 439M07000
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- BORE - OVERSIZE:
- STANDARD
- BORE - OVERSIZE METRIC:
- STANDARD
- BORE SIZE METRIC:
- 70.00 MM
- PRODUCT NAME:
- PISTON KIT
- SKIRT COATING:
- NON-COATED
- UNITS:
- KIT
- PISTON MATERIAL:
- 4032 ALUMINUM ALLOY
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- MODEL:
- FORGED SERIES
- PISTON DIAMETER METRIC:
- 69.95 MM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- STROKE LENGTH METRIC:
- 64.90 MM
- DISPLACEMENT:
- 249 CC
- ENGINE TYPE:
- 2-STROKE
$221.95Qty in Cart: 0Quantity:Price:$221.95Subtotal: -
Wiseco Piston Kit 1mm Oversize 76.95mm 10.5:1 Compression Honda XL250R 1984-1987 4329M07600
WISECO
$194.95If you're rebuilding a Honda XL250R or XR250R engine, this Wiseco piston kit delivers the bore size and compression ratio needed for reliable power restoration or modest performance gains. The 1mm...4329M07600- SKU:
- 4329M07600
- Availability:
- Ships Same Business Day
- Weight:
- 0.75 LBS
- BORE - OVERSIZE METRIC:
- +1.00 MM
- RIDING STYLE:
- OFF-ROAD
- SKIRT COATING:
- NON-COATED
- UNITS:
- KIT
- COMPRESSION RATIO IMPERIAL:
- 10.5:1
- ENGINE TYPE:
- 4-STROKE
- BORE - OVERSIZE:
- +1,00 MM
- BORE SIZE METRIC:
- 76.00 MM
- DISPLACEMENT:
- 250 CC
- MODEL:
- FORGED SERIES
- PRODUCT NAME:
- PISTON KIT
- PISTON DIAMETER METRIC:
- 75.95 MM
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- STROKE LENGTH METRIC:
- 56.50 MM
$194.95 -
HOT RODS Connecting Rod 8129
HOT RODS
$135.95When you're pushing your engine to the limit, your connecting rods need to handle extreme loads and sustained high-RPM operation without compromise. The HOT RODS 8129 is engineered for engines that...423108- SKU:
- 423108
- Availability:
- Ships Same Business Day
- Weight:
- 0.81 LBS
- ENGINE TYPE:
- 2-CYCLE
- MATERIAL:
- 8620 STEEL
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- FEATURES:
- INCLUDES THRUST WASHERS
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$135.95 -
HOT RODS Connecting Rod 8163
HOT RODS
$135.95When you're pushing your engine to its limits, your connecting rods are working harder than any other component in your drivetrain. The HOT RODS 8163 Connecting Rod is engineered for sustained...423103- SKU:
- 423103
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
- FEATURES:
- INCLUDES THRUST WASHERS
- PRODUCT NAME:
- CONNECTING ROD KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- ENGINE TYPE:
- 2-CYCLE
- MATERIAL:
- 8620 STEEL
$135.95Qty in Cart: 0Quantity:Price:$135.95Subtotal: -
On Sale
ATHENA Complete Gasket Kit - Suzuki P400510850261
ATHENA
MSRP: $37.95Now: $32.00Was: $37.95A complete gasket kit is essential for any top-end rebuild or full engine overhaul—it ensures reliable sealing across all critical interfaces and prevents fluid leaks that compromise performance and...400510850261- SKU:
- 400510850261
- Availability:
- Ships Same Business Day
- Weight:
- 0.31 LBS
MSRP: $37.95Now: $32.00Was: $37.95 -
On Sale
ATHENA Complete Gasket Kit - Suzuki P400510850252
ATHENA
MSRP: $69.95Now: $63.00Was: $69.95A complete gasket kit is essential for any top-end or full engine rebuild—sealing failures lead to compression loss, oil leakage, and catastrophic engine damage. Athena's engineering prioritizes...400510850252- SKU:
- 400510850252
- Availability:
- Ships Same Business Day
- Weight:
- 4.00 LBS
MSRP: $69.95Now: $63.00Was: $69.95Qty in Cart: 0Quantity:Price:MSRP: $69.95Now: $63.00Was: $69.95Subtotal: -
On Sale
ATHENA Complete Gasket Kit - Suzuki P400510850241
ATHENA
MSRP: $74.95Now: $67.00Was: $74.95A complete engine gasket kit is essential for any top-end rebuild or full engine overhaul, and the ATHENA P400510850241 delivers the reliability needed for sustained high-performance operation...400510850241- SKU:
- 400510850241
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
MSRP: $74.95Now: $67.00Was: $74.95Qty in Cart: 0Quantity:Price:MSRP: $74.95Now: $67.00Was: $74.95Subtotal: -
On Sale
ATHENA Complete Gasket Kit - Suzuki P400510850125
ATHENA
MSRP: $42.95Now: $37.00Was: $42.95A complete gasket kit is essential when rebuilding your engine—using OEM-quality seals ensures reliable compression, prevents fluid leakage, and maintains peak performance across all operating...400510850125- SKU:
- 400510850125
- Availability:
- Ships Same Business Day
- Weight:
- 0.31 LBS
MSRP: $42.95Now: $37.00Was: $42.95 -
On Sale
ATHENA Top End Gasket Kit - Suzuki P400510600143
ATHENA
MSRP: $32.95Now: $28.00Was: $32.95A top-end gasket kit is essential maintenance for any racer looking to maximize engine reliability and performance between rebuild cycles. The ATHENA P400510600143 gives you the flexibility to run...400510600143- SKU:
- 400510600143
- Availability:
- Ships Same Business Day
- Weight:
- 0.13 LBS
MSRP: $32.95Now: $28.00Was: $32.95 -
On Sale
ATHENA Top End Gasket Kit - Suzuki P400510600013
ATHENA
MSRP: $11.95Now: $10.00Was: $11.95Engine gasket integrity is critical when you're preparing for race season—a single leak can cost you lap time and reliability when it matters most. The ATHENA Top End Gasket Kit gives you the...4.00511E+11- SKU:
- 4.00511E+11
- Availability:
- Ships Same Business Day
- Weight:
- 0.00 LBS
MSRP: $11.95Now: $10.00Was: $11.95 -
On Sale
ATHENA Complete Gasket Kit - Yamaha P400485850490
ATHENA
MSRP: $34.95Now: $31.00Was: $34.95When you're rebuilding an engine, gasket failure isn't an option—it's a catastrophe. The ATHENA Complete Gasket Kit delivers the reliability you need across all critical sealing points, combining...400485850490- SKU:
- 400485850490
- Availability:
- Ships Same Business Day
- Weight:
- 0.31 LBS
MSRP: $34.95Now: $31.00Was: $34.95Qty in Cart: 0Quantity:Price:MSRP: $34.95Now: $31.00Was: $34.95Subtotal:
