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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- Price
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COMETIC Top End Gasket Kit - 97 mm - Suzuki C3233-EST
COMETIC
$89.95A quality gasket kit is the foundation of a reliable top end—any leakage or failure here compromises both power output and engine longevity. Cometic's EST gasket kit seals critical surfaces with multi-layered steel construction and proprietary Viton...09347827- SKU:
- 09347827
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
$89.95 -
COMETIC Top End Gasket Kit - 99 mm - Suzuki C3234-EST
COMETIC
$89.95A failing top end gasket compromises combustion sealing and invites coolant leaks that sideline your build. The COMETIC EST kit delivers multi-layered steel construction with Viton rubber coating to handle sustained high-cylinder-pressure loads, whether...09347828- SKU:
- 09347828
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
$89.95 -
COMETIC Top End Gasket Kit - 101 mm - Suzuki C3235-EST
COMETIC
$89.95A quality top-end gasket kit is non-negotiable for maintaining cylinder pressure and preventing combustion leakage, especially when running high-output naturally aspirated or forced-induction setups. COMETIC's EST (Extreme Sealing Technology) design uses...09347831- SKU:
- 09347831
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
$89.95 -
COMETIC Top End Gasket Kit - 77 mm - Suzuki C3406-EST
COMETIC
$69.95A failing head gasket compromises cylinder pressure, kills power output, and leaves you stranded. Cometic's EST gasket kit delivers the multi-layered steel construction and Viton rubber coating engineered to handle today's high-output 4-stroke...09347832- SKU:
- 09347832
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
$69.95 -
COMETIC Top End Gasket Kit - 79 mm - Suzuki C3407-EST
COMETIC
$69.95A failing top-end gasket kit compromises combustion sealing and engine reliability—especially on high-output 4-stroke builds. Cometic's EST (Extreme Sealing Technology) gasket kit uses multi-layered steel construction with proprietary Viton rubber...09347833- SKU:
- 09347833
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
$69.95 -
COMETIC Top End Gasket Kit - 80 mm - Suzuki C3408-EST
COMETIC
$69.95A failing head gasket doesn't just leak—it compromises cylinder pressure, kills power output, and can leave you stranded. The COMETIC Top End Gasket Kit uses multi-layered steel construction with Viton rubber coating to handle the extreme pressures of...09347834- SKU:
- 09347834
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
$69.95 -
COMETIC Top End Gasket Kit - 82 mm - Suzuki C3409-EST
COMETIC
$69.95A top-end gasket failure can cost you a race and months of downtime. The COMETIC C3409-EST uses multi-layered steel construction with Viton rubber coating to handle the extreme pressures of modern 4-stroke engines, delivering reliable sealing on both...09347836- SKU:
- 09347836
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
$69.95 -
COMETIC Top End Gasket Kit - 84 mm - Suzuki C3410-EST
COMETIC
$69.95A compromised top-end gasket kit leads to compression loss, coolant seepage, and catastrophic engine failure. Cometic's EST gasket kit delivers the sealing integrity and thermal management your high-output engine demands, whether you're running naturally...09347837- SKU:
- 09347837
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
$69.95 -
COMETIC Top End Gasket Kit - 97 mm - Yamaha C3540-EST
COMETIC
$68.95A top-end gasket kit failure can compromise your engine's seal integrity and cost you horsepower—especially in high-boost or naturally aspirated applications pushing cylinder pressures to the limit. Cometic's EST (Extreme Sealing Technology) design uses...09347839- SKU:
- 09347839
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
$68.95 -
COMETIC Top End Gasket Kit - 52.5 mm - Kawasaki C3542
COMETIC
$31.95A compromised top-end seal means lost compression, oil weeping, and catastrophic engine failure—especially under high boost or sustained high RPM. The COMETIC C3542 gasket kit eliminates these risks with MLS (multi-layered steel) construction and EST...09347840- SKU:
- 09347840
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
$31.95 -
COMETIC Top End Gasket Kit - 88 mm - KTM C3605-EST
COMETIC
$74.95A failing top-end gasket kit compromises cylinder pressure, reduces power output, and risks catastrophic engine damage. The COMETIC C3605-EST delivers the sealing reliability you need for high-horsepower 4-stroke engines, whether naturally aspirated or...09347843- SKU:
- 09347843
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
$74.95 -
COMETIC Top End Gasket Kit - 96 mm - Honda C3621
COMETIC
$85.95A failing top end gasket compromises combustion seal integrity, leading to lost compression, oil leakage, and costly engine damage. The COMETIC C3621 kit delivers the precision sealing your high-output engine demands, whether you're running naturally...09347844- SKU:
- 09347844
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
$85.95 -
COMETIC Top End Gasket Kit - 97 mm - Yamaha C3630
COMETIC
$53.95A failing top end gasket can cost you races, reliability, and engine integrity. This Cometic gasket kit delivers the sealing performance required for high-output 4-stroke engines—whether naturally aspirated or boosted—using multi-layered steel...09347845- SKU:
- 09347845
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
$53.95 -
COMETIC Top End Gasket Kit - 77 mm - Yamaha C3695
COMETIC
$79.95A failing head gasket doesn't just cost you power—it costs you reliability. The COMETIC Top End Gasket Kit ensures a proper seal under high combustion pressures, whether you're running naturally aspirated or forced induction. With multi-layered steel...09347847- SKU:
- 09347847
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
$79.95 -
COMETIC Top End Gasket Kit/O-Ring Cylinder Head Gasket - Yamaha C3731
COMETIC
$39.95A top-end gasket kit is essential for any cylinder head removal or rebuild—whether you're performing routine maintenance or a complete engine overhaul. Using OEM-equivalent seals ensures proper compression, prevents oil and coolant leaks, and maintains...09347849- SKU:
- 09347849
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
$39.95 -
COMETIC Top End Gasket Kit - 82 mm - Honda C3735
COMETIC
$67.95A top-end rebuild demands gasket integrity that matches your engine's output. Cometic's MLS head gaskets and EST technology eliminate hot spots and bore distortion, ensuring consistent sealing under high cylinder pressures—whether naturally aspirated or...09347851- SKU:
- 09347851
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
$67.95 -
COMETIC Top End Gasket Kit - KTM/Husqvarna C3808
COMETIC
$92.95A failing head gasket means catastrophic engine damage and downtime you can't afford. The COMETIC C3808 top end gasket kit delivers the sealing integrity and thermal stability required to handle today's high-output 4-stroke engines—whether naturally...09347802- SKU:
- 09347802
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
$92.95 -
COMETIC Top End Gasket Kit - 90 mm - KTM C3779-EST
COMETIC
$74.95A quality top end gasket kit is non-negotiable when you're rebuilding or maintaining a high-output 4-stroke engine. Cometic's EST technology delivers superior sealing integrity under extreme combustion pressures, preventing blow-by and power loss that...09347853- SKU:
- 09347853
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
$74.95 -
COMETIC Top End Gasket Kit - KTM/Husqvarna/Gas Gas C3623
COMETIC
$46.95A top-end rebuild demands precision gasket sealing to contain combustion pressures and maintain ring seal—especially in high-output 4-stroke engines where even minor leakage degrades performance and reliability. The COMETIC C3623 kit delivers the exact...09347804- SKU:
- 09347804
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
$46.95 -
COMETIC Top End Gasket Kit - 79 mm - KTM/Husqvarna/Gas Gas C3595-EST
COMETIC
$87.95A top-end gasket failure can sideline your bike mid-season, and inferior gaskets invite compression loss, oil leaks, and catastrophic engine damage. The COMETIC EST gasket kit eliminates guesswork with precision-engineered sealing surfaces and...09347806- SKU:
- 09347806
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
$87.95
