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!
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- Quantity
- Price
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On Sale
ATHENA Top End Gasket Kit - Honda P400210600210
ATHENA
MSRP: $34.95Now: $31.00Was: $34.95Engine freshness directly impacts race day performance, and the ATHENA Top End Gasket Kit gives you the precision sealing needed to maximize compression and fuel efficiency. Whether you're running stock gas with standard compression or stepping up to...400210600210- SKU:
- 400210600210
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
MSRP: $34.95Now: $31.00Was: $34.95 -
On Sale
ATHENA Top End Gasket Kit - Honda P400210600126
ATHENA
MSRP: $33.95Now: $31.00Was: $33.95A fresh top end gasket kit is essential before hitting the track, ensuring a proper seal that maintains compression integrity and prevents mid-race failures. The ATHENA P400210600126 gives you the flexibility to optimize your engine for either pump gas...400210600126- SKU:
- 400210600126
- Availability:
- Ships Same Business Day
- Weight:
- 0.13 LBS
MSRP: $33.95Now: $31.00Was: $33.95 -
On Sale
ATHENA Top End Gasket Kit - Honda P400210600103
ATHENA
MSRP: $27.95Now: $25.00Was: $27.95When race season demands peak performance, engine reliability becomes non-negotiable. The ATHENA Top End Gasket Kit is engineered for riders who won't compromise on compression ratios or fuel choice—giving you the flexibility to run standard fuel with...400210600103- SKU:
- 400210600103
- Availability:
- Ships Same Business Day
- Weight:
- 0.19 LBS
MSRP: $27.95Now: $25.00Was: $27.95 -
Wiseco Piston Kit 1mm Oversize 71mm Bore for Suzuki DS250 1980 380M07100
WISECO
$210.95If you're running a Suzuki DS250 and want to unlock additional displacement and power without a complete engine overhaul, this 1mm oversize Wiseco piston kit is your answer. The forged aluminum construction combined with precision ring design ensures...380M07100- SKU:
- 380M07100
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
- BORE - OVERSIZE:
- +1,00 MM
- BORE SIZE METRIC:
- 71.00 MM
- DISPLACEMENT:
- 246 CC
- MODEL:
- FORGED SERIES
- PRODUCT NAME:
- PISTON KIT
- STROKE LENGTH METRIC:
- 64.00 MM
- BORE - OVERSIZE METRIC:
- +1.00 MM
- PISTON DIAMETER METRIC:
- 70.92 MM
- SKIRT COATING:
- NON-COATED
- UNITS:
- KIT
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- 4032 ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
$210.95 -
Wiseco Piston Kit Suzuki TS250 1973-1981 70mm 380M07000
WISECO
$210.95Whether you're rebuilding a tired TS250 or maximizing output on an already-strong platform, a quality piston kit is foundational to reliable power delivery. Wiseco's 380M07000 delivers the precision bore diameter and material science necessary for...380M07000- SKU:
- 380M07000
- Availability:
- Ships Same Business Day
- Weight:
- 0.75 LBS
- BORE - OVERSIZE:
- STANDARD
- DISPLACEMENT:
- 246 CC
- MODEL:
- FORGED SERIES
- SKIRT COATING:
- NON-COATED
- BORE - OVERSIZE METRIC:
- STANDARD
- BORE SIZE METRIC:
- 70.00 MM
- PISTON DIAMETER METRIC:
- 69.92 MM
- PRODUCT NAME:
- PISTON KIT
- STROKE LENGTH METRIC:
- 64.00 MM
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- 4032 ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$210.95 -
Wiseco 85mm Piston Ring Set for Honda TRX400EX 1999-2008 3347XC
WISECO
$52.95Piston rings are critical to maintaining compression, controlling blow-by, and delivering consistent power output in your TRX400EX engine. Over time, factory rings wear and lose their sealing ability, resulting in lost horsepower, increased oil...3347XC- SKU:
- 3347XC
- Availability:
- Ships Same Business Day
- Weight:
- 0.13 LBS
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- PISTON MATERIAL:
- ALUMINUM
- BORE SIZE METRIC:
- 85.00 MM
- PRODUCT NAME:
- PISTON RING
- RIDING STYLE:
- STREET
- UNITS:
- SET
$52.95 -
Wiseco Piston Ring Set 85mm Bore 1995-2000 Polaris Scrambler 400 3347TD
WISECO
$57.95Piston ring seal integrity is critical for maintaining compression, controlling blow-by, and maximizing fuel efficiency in high-demand riding conditions. The Wiseco 3347TD delivers precision-engineered rings that work seamlessly with Wiseco pistons,...3347TD- SKU:
- 3347TD
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- PRODUCT NAME:
- PISTON RING
- BORE SIZE METRIC:
- 85.00 MM
- RIDING STYLE:
- ATV
- PISTON MATERIAL:
- ALUMINUM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- SET
$57.95 -
HOT RODS Water Pump Shaft HRSHA-002
HOT RODS
$63.95A worn water pump shaft compromises cooling system integrity and accelerates seal degradation, leading to leaks and potential engine overheating. The HOT RODS Water Pump Shaft HRSHA-002 restores OE-specification performance with precision engineering and...09500575- SKU:
- 09500575
- Availability:
- Ships Same Business Day
- Weight:
- 0.14 LBS
- TYPE:
- WATER PUMP
- PRODUCT NAME:
- SHAFT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$63.95 -
HOT RODS Water Pump Shaft HRSHA-001
HOT RODS
$63.95A worn water pump shaft compromises cooling system efficiency and invites premature seal failure—both risks that can sideline your engine. This OE-quality replacement restores proper coolant circulation with a polished surface finish that minimizes...09500574- SKU:
- 09500574
- Availability:
- Ships Same Business Day
- Weight:
- 0.13 LBS
- TYPE:
- WATER PUMP
- PRODUCT NAME:
- SHAFT
- RIDING STYLE:
- STREET
- UNITS:
- EACH
$63.95 -
HOT RODS Output Shaft Seal OSK0058
HOT RODS
$35.95Countershaft seal leaks can compromise transmission reliability and lead to costly damage if left unaddressed. The HOT RODS Output Shaft Seal kit (OSK0058) provides everything needed to repair the leak in a single, complete package—eliminating the hassle...09350954- SKU:
- 09350954
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- APPLICATION:
- COUNTERSHAFT
- TYPE:
- OIL
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- SEAL KIT
- UNITS:
- KIT
$35.95 -
Cylinder Works YZ250 1999-2024 Big Bore Power Valve Kit CW-PV-K02
CYLINDER WORKS
$394.95The YZ250 power valve is critical to your engine's mid-range and top-end performance—restrict its movement, and you're leaving horsepower on the table. Cylinder Works' big bore kit restores optimal valve function with CNC precision, directly improving...09350953- SKU:
- 09350953
- Availability:
- Ships Same Business Day
- Weight:
- 0.35 LBS
- COLOR/FINISH:
- ANODIZED
- MATERIAL:
- STEEL
- COLOR/FINISH:
- BLACK
- PRODUCT NAME:
- POWER VALVE
- BORE SIZE METRIC:
- 72.00 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$394.95 -
Cylinder Works Power Valve Kit Standard Bore Yamaha YZ250 1999-2021 CW-PV-K01
CYLINDER WORKS
$252.95The YZ250's power valve is critical to maximizing mid-range punch and throttle response—and a worn or poorly-designed unit robs you of significant horsepower across the entire powerband. The Cylinder Works CW-PV-K01 restores precision control over your...09350952- SKU:
- 09350952
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BORE SIZE METRIC:
- STOCK BORE CYLINDER
- COLOR/FINISH:
- BLACK
- PRODUCT NAME:
- POWER VALVE
- COLOR/FINISH:
- ANODIZED
$252.95 -
COMETIC Crank Seal Kit C7803
COMETIC
$17.95A compromised crank seal is an invisible threat to engine integrity—leaking oil, inviting contamination, and accelerating internal wear. The COMETIC Crank Seal Kit C7803 delivers OE-equivalent sealing performance with the precision engineering that...09350811- SKU:
- 09350811
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- SEAL
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- APPLICATION:
- CRANKSHAFT
- TYPE:
- OIL
$17.95 -
HOT RODS Seal Output Shaft OSK0029
HOT RODS
$37.95A leaking countershaft seal drains performance and reliability from your transmission, leaving you stranded trackside or compromising engine longevity. The HOT RODS Seal Output Shaft kit delivers everything needed to stop the leak and restore proper...09350592- SKU:
- 09350592
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- APPLICATION:
- COUNTERSHAFT
- APPLICATION:
- TRANSMISSION
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- SEAL
$37.95 -
HOT RODS Seal Output Shaft OSK0026
HOT RODS
$35.95A leaking countershaft seal will compromise your transmission's integrity and lead to catastrophic failure if left unaddressed. This complete kit eliminates guesswork by bundling every component you need to restore a proper seal in one purchase, saving...09350590- SKU:
- 09350590
- Availability:
- Ships Same Business Day
- Weight:
- 0.14 LBS
- APPLICATION:
- COUNTERSHAFT
- APPLICATION:
- TRANSMISSION
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- SEAL
$35.95 -
HOT RODS Seal Output Shaft OSK0018
HOT RODS
$37.95A leaking countershaft seal compromises your transmission's integrity and can lead to costly damage if left unaddressed. The HOT RODS Seal Output Shaft kit delivers everything you need to fix the problem in one complete package—no hunting for individual...09350582- SKU:
- 09350582
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- SEAL
- APPLICATION:
- COUNTERSHAFT
- APPLICATION:
- TRANSMISSION
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$37.95 -
HOT RODS Seal Output Shaft OSK0015
HOT RODS
$34.95A leaking countershaft seal creates cascading problems—oil loss, bearing contamination, and potential drivetrain failure. The HOT RODS Seal Output Shaft kit eliminates guesswork by delivering everything you need in a single, proven package, saving you...09350580- SKU:
- 09350580
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- SEAL
- APPLICATION:
- COUNTERSHAFT
- APPLICATION:
- TRANSMISSION
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$34.95 -
HOT RODS Seal Output Shaft OSK0012
HOT RODS
$34.95A leaking countershaft seal will compromise your transmission's integrity and lead to costly damage if left unaddressed. This complete kit eliminates the guesswork by bundling every component needed for a proper repair in one order. Get your drivetrain...09350578- SKU:
- 09350578
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- APPLICATION:
- COUNTERSHAFT
- APPLICATION:
- TRANSMISSION
- PRODUCT NAME:
- SEAL
$34.95 -
MOOSE RACING Gasket set with oil seal - YZ65 8110008
MOOSE RACING
$73.20A complete engine and transmission rebuild demands precision-fit components that won't compromise your reliability. MOOSE RACING's gasket and oil seal set delivers OEM-quality replacement parts at a fraction of the cost, allowing you to restore your YZ65...09346582- SKU:
- 09346582
- Availability:
- Ships Same Business Day
- Weight:
- 0.26 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- ENGINE
- PRODUCT NAME:
- GASKET
- UNITS:
- KIT
$73.20 -
On Sale
ATHENA Water Pump Gasket Kit - Kawasaki P400250475014
ATHENA
MSRP: $47.95Now: $43.00Was: $47.95Coolant leaks and oil seepage compromise engine reliability and performance—two things you can't afford to ignore on the track or in your build. The ATHENA Water Pump Gasket Kit addresses these critical sealing points with OEM-quality gaskets and seals...09346062- SKU:
- 09346062
- Availability:
- Ships Same Business Day
- Weight:
- 0.27 LBS
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- ENGINE TYPE:
- 2-STROKE
- TYPE:
- WATER PUMP
- UNITS:
- KIT
MSRP: $47.95Now: $43.00Was: $47.95
