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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- Qty in Cart
- Quantity
- Price
- Subtotal
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COMETIC Top End Gasket Set - KTM C3503
COMETIC
$36.95A failing top-end gasket will cost you far more than the price of this kit—lost compression, oil weeping, and catastrophic engine damage happen fast on high-output 4-stroke machines. The COMETIC C3503 gasket set is engineered to handle the extreme...09344189- SKU:
- 09344189
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- BORE SIZE METRIC:
- 39.00 MM
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- PRODUCT NAME:
- GASKET KIT
- UNITS:
- KIT
$36.95 -
COMETIC Bottom End Gasket Set - KTM C3517
COMETIC
$47.95A complete bottom end gasket kit is essential for any engine rebuild—sealing leaks and maintaining compression are non-negotiable for reliability and performance. COMETIC's C3517 gasket set includes every seal, O-ring, and washer needed to properly...09344200- SKU:
- 09344200
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- BOTTOM END
- MODEL:
- HI-PERFORMANCE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$47.95 -
COMETIC Top End Gasket Set - Kawasaki C3541
COMETIC
$33.95A quality top-end gasket set is critical to maintaining reliable compression and preventing combustion blow-by, especially when running elevated boost or high naturally-aspirated power levels. The COMETIC C3541 combines multi-layered steel construction...09344208- SKU:
- 09344208
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- THICKNESS IMPERIAL:
- 0,012'
- PRODUCT NAME:
- GASKET KIT
- THICKNESS METRIC:
- 0.31 MM
- BORE SIZE METRIC:
- 48.50 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- TOP END
$33.95 -
On Sale
COMETIC Top End Gasket Set - Yamaha C3550-EST
COMETIC
MSRP: $75.95Now: $49.00Was: $75.95A quality top end gasket set is non-negotiable for engines pushing high horsepower and cylinder pressure—factory gaskets simply aren't engineered to handle sustained boost or naturally aspirated outputs. The COMETIC C3550-EST uses multi-layered steel...09344213- SKU:
- 09344213
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
- BORE SIZE METRIC:
- 80.00 MM
- THICKNESS IMPERIAL:
- 0,027'
- THICKNESS METRIC:
- 0.25 MM
- THICKNESS IMPERIAL:
- 0,010'
- THICKNESS METRIC:
- 0.69 MM
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- GASKET KIT
MSRP: $75.95Now: $49.00Was: $75.95 -
COMETIC Stator Gasket - Kawasaki EC1081032AFM
COMETIC
$16.95Stator cover gasket failures lead to oil seepage, contaminated ignition systems, and costly engine damage. The COMETIC Stator Gasket eliminates the frustration of repeated failures and difficult replacements by combining a bonded aluminum core with AFM...09344372- SKU:
- 09344372
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- MATERIAL:
- AFM (ALUMINUM FOAM MATERIAL)
- MODEL:
- HI-PERFORMANCE
- PRODUCT NAME:
- GASKET
- THICKNESS:
- 0,81 MM (0,032')
- THICKNESS IMPERIAL:
- 0,032'
- THICKNESS METRIC:
- 0.81 MM
- UNITS:
- EACH
- TYPE:
- STATOR COVER
- RIDING STYLE:
- OFF-ROAD
$16.95 -
COMETIC Clutch Gasket - Kawasaki EC1102018AFM
COMETIC
$8.95Clutch cover gasket failure leads to oil seepage, contamination, and costly engine rebuilds. The COMETIC EC1102018AFM eliminates these headaches with an AFM composite construction that delivers a superior seal without sealants, reducing installation time...09344376- SKU:
- 09344376
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH COVER
- MODEL:
- HI-PERFORMANCE
- PRODUCT NAME:
- GASKET
- UNITS:
- EACH
$8.95 -
COMETIC Clutch Gasket - Kawasaki EC1184032AFM
COMETIC
$15.95A quality clutch gasket is critical to preventing oil seepage and maintaining consistent clutch engagement—degraded gaskets lead to costly fluid loss and potential clutch contamination. COMETIC's AFM gasket delivers superior sealing with an...09344384- SKU:
- 09344384
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- RIDING STYLE:
- ATV
- TYPE:
- CLUTCH COVER
- UNITS:
- EACH
- MODEL:
- HI-PERFORMANCE
- PRODUCT NAME:
- GASKET
- THICKNESS IMPERIAL:
- 0,032'
- RIDING STYLE:
- OFF-ROAD
$15.95 -
COMETIC Stator Gasket - Honda EC1416032AFM
COMETIC
$19.95If you're tired of gasket scraping and repeat leaks at the stator cover, the COMETIC AFM gasket eliminates both problems with its bonded aluminum core and superior sealing geometry. This gasket won't stick to your engine case, cutting service time...09344394- SKU:
- 09344394
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- STATOR COVER
- MATERIAL:
- AFM (ALUMINUM FOAM MATERIAL)
- PRODUCT NAME:
- GASKET
- UNITS:
- EACH
- MODEL:
- HI-PERFORMANCE
$19.95 -
COMETIC Clutch Gasket - Yamaha EC470020F
COMETIC
$9.95A worn or failing clutch cover gasket leads to oil weeping, potential case damage, and costly downtime. The COMETIC Clutch Gasket eliminates these headaches with a dual-layer AFM construction that seals reliably without sealants, reduces service time,...09344462- SKU:
- 09344462
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH COVER
- UNITS:
- EACH
- PRODUCT NAME:
- GASKET
- MODEL:
- HI-PERFORMANCE
$9.95 -
COMETIC Exhaust Gasket EX456010S
COMETIC
$7.95Exhaust gasket failure is one of the quickest ways to compromise engine sealing and lose performance gains—especially under high heat and boost conditions. The COMETIC EX456010S delivers the thermal stability and structural integrity you need to keep...09344538- SKU:
- 09344538
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- SET
- BORE SIZE METRIC:
- 68.50 MM
- MODEL:
- HI-PERFORMANCE
- TYPE:
- EXHAUST
- PRODUCT NAME:
- GASKET
$7.95 -
COMETIC Exhaust Gasket - Yamaha EX641
COMETIC
$13.95Exhaust gasket failure is one of the most common causes of performance loss and costly engine damage. The COMETIC EX641 eliminates guesswork with precision engineering designed to handle extreme combustion temperatures while resisting blow-outs from...09344541- SKU:
- 09344541
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- BORE SIZE METRIC:
- 100.00 MM
- UNITS:
- SET
- RIDING STYLE:
- OFF-ROAD
- MODEL:
- HI-PERFORMANCE
- TYPE:
- EXHAUST
- PRODUCT NAME:
- GASKET
$13.95 -
COMETIC Exhaust Gasket EX657
COMETIC
$11.95Exhaust gasket failure leads to costly leaks, lost horsepower, and potential engine damage—especially under high-heat or high-boost conditions. The COMETIC EX657 is engineered to seal reliably across extreme temperature ranges, eliminating the risk of...09344545- SKU:
- 09344545
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- RIDING STYLE:
- ATV
- TYPE:
- EXHAUST
- MODEL:
- HI-PERFORMANCE
- PRODUCT NAME:
- GASKET
- BORE SIZE METRIC:
- 99.00 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- SET
$11.95 -
COMETIC Exhaust Gasket - Honda EX690064AM
COMETIC
$4.95Exhaust gasket failure leads to power loss, heat damage, and costly engine complications. The COMETIC EX690064AM delivers reliable, high-temperature sealing that won't fail under extreme conditions or aggressive tuning. Built with domestic precision and...09344546- SKU:
- 09344546
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- BORE SIZE METRIC:
- 39.00 MM
- RIDING STYLE:
- ATV
- MODEL:
- HI-PERFORMANCE
- PRODUCT NAME:
- GASKET
- THICKNESS METRIC:
- 1.63 MM
- TYPE:
- EXHAUST
- UNITS:
- SET
- RIDING STYLE:
- OFF-ROAD
- THICKNESS IMPERIAL:
- 0,064'
$4.95 -
COMETIC Exhaust Gasket EX817
COMETIC
$13.95Exhaust gasket failure means boost leaks, power loss, and costly engine damage—especially under high heat and pressure. The COMETIC EX817 is engineered for extreme conditions with a dual-layer construction that seals reliably across 4-stroke...09344554- SKU:
- 09344554
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- TYPE:
- EXHAUST
- UNITS:
- SET
- MODEL:
- HI-PERFORMANCE
- PRODUCT NAME:
- GASKET
- BORE SIZE METRIC:
- 90.00 MM
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- UTV
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- ATV
- RIDING STYLE:
- STREET
$13.95 -
COMETIC Valve Cover Gasket - Honda VC032010S
COMETIC
$39.95A failing valve cover gasket will bleed oil onto your engine bay and compromise your engine's cleanliness—exactly what you don't want during a race or on the street. The COMETIC VC032010S delivers OEM-quality sealing at a fraction of the cost, using...09344566- SKU:
- 09344566
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- VALVE COVER
- MODEL:
- HI-PERFORMANCE
- MATERIAL:
- ALUMINUM
- PRODUCT NAME:
- GASKET
- UNITS:
- EACH
$39.95 -
COMETIC Stator Gasket - Kawasaki EC1339032AFM
COMETIC
$16.95Stator cover gasket failures are costly downtime culprits—they weep, crawl, and demand tedious scraping during replacement. The COMETIC Stator Gasket eliminates these headaches with its AFM composite construction, delivering a reliable seal without...09344392- SKU:
- 09344392
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- MODEL:
- HI-PERFORMANCE
- PRODUCT NAME:
- GASKET
- TYPE:
- STATOR COVER
- RIDING STYLE:
- OFF-ROAD
- MATERIAL:
- AFM (ALUMINUM FOAM MATERIAL)
- UNITS:
- EACH
$16.95 -
Hot Cams Valve Shim 10.0 x 2.25 for 2008-2010 KTM 530 EXC-R 5PK1000225
HOT CAMS
$11.95Valve shim wear directly impacts your KTM 530 EXC-R's compression, valve timing, and overall engine responsiveness. This five-piece Hot Cams replacement pack gives you the precision shims needed to maintain tight tolerances and consistent performance...09261282- SKU:
- 09261282
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- OUTSIDE DIAMETER METRIC:
- 10.00 MM
- TYPE:
- VALVE
- PRODUCT NAME:
- SHIM
- UNITS:
- 5 PACK
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- VALVE SHIM THICKNESS METRIC:
- 2.25 MM
$11.95 -
Hot Cams Valve Shim Kit 7.48mm OD 1.20-3.50mm Honda CRF150R 2007-2022 HCSHIM01
HOT CAMS
$10.95Maintaining precise valve clearance is critical to keeping your CRF150R running at peak efficiency—and worn or mismatched shims will compromise both power delivery and engine longevity. The Hot Cams Valve Shim Kit gives you the exact OD and thickness...09261302- SKU:
- 09261302
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- OUTSIDE DIAMETER METRIC:
- 7.48 MM
- RIDING STYLE:
- ATV
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- UTV
- TYPE:
- VALVE
- RIDING STYLE:
- STREET
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 1.20 MM
$10.95 -
Hot Cams Stage 1 Intake Camshaft for Yamaha YZ250F 2001-2013 4012-1IN
HOT CAMS
$335.95If you're running a YZ250F and want measurable gains in low-end torque and throttle response, the Hot Cams Stage 1 Intake Camshaft is a bolt-on upgrade that delivers without requiring valve spring replacement. This cam's ITR technology sharpens your...YZ250S1AI- SKU:
- YZ250S1AI
- Availability:
- Ships Same Business Day
- Weight:
- 0.90 LBS
- UNITS:
- EACH
- APPLICATION:
- INTAKE
- INTAKE DURATION IMPERIAL:
- 249°
- INTAKE LIFT METRIC:
- 8.48 MM
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- CAMSHAFT
$335.95 -
Hot Cams Stage 1 Intake Camshaft for Yamaha WR 400 F 1998-2000 4002-1IN
HOT CAMS
$294.95If you're running a WR 400 F and want genuine low-end grunt without compromising reliability, the Hot Cams Stage 1 intake camshaft is the straightforward upgrade that delivers. This is a bolt-on cam that works with your stock valve springs, meaning you...YZ426S1AI- SKU:
- YZ426S1AI
- Availability:
- Ships Same Business Day
- Weight:
- 1.00 LBS
- PRODUCT NAME:
- CAMSHAFT
- INTAKE LIFT METRIC:
- 8.80 MM
- INTAKE DURATION IMPERIAL:
- 260°
- APPLICATION:
- INTAKE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$294.95
