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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On Sale
COMETIC Top End Gasket Kit - 90 mm - KTM/Husqvarna/Gas Gas C3790
COMETIC
MSRP: $97.95Now: $88.16Was: $97.95A worn or failing top-end gasket kit compromises combustion sealing and invites coolant or oil leakage—both costly problems for high-performance engines. The COMETIC C3790 kit delivers the precision...09347857- SKU:
- 09347857
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
MSRP: $97.95Now: $88.16Was: $97.95 -
On Sale
COMETIC Top End Gasket Kit - Kawasaki C3803
COMETIC
MSRP: $84.95Now: $76.46Was: $84.95A failing top end gasket compromises cylinder pressure, bleeds horsepower, and risks catastrophic engine damage—especially in high-output 4-stroke engines running forced induction or extreme...09347860- SKU:
- 09347860
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
MSRP: $84.95Now: $76.46Was: $84.95Qty in Cart: 0Quantity:Price:MSRP: $84.95Now: $76.46Was: $84.95Subtotal: -
On Sale
COMETIC Top End Gasket Kit - 96 mm - Kawasaki C3806
COMETIC
MSRP: $88.95Now: $80.06Was: $88.95A quality gasket kit is non-negotiable for any top-end rebuild—it's the barrier between combustion pressures and coolant passages, and failure means catastrophic engine damage. The COMETIC C3806 uses...09347861- SKU:
- 09347861
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
MSRP: $88.95Now: $80.06Was: $88.95 -
On Sale
COMETIC Top End Gasket Kit - 48 mm - Kawasaki/Suzuki C7737
COMETIC
MSRP: $28.95Now: $26.06Was: $28.95A failing top end gasket compromises combustion chamber sealing, causing power loss, coolant leakage, and potential engine damage. The COMETIC C7737 kit delivers OEM-spec sealing with multi-layered...09347867- SKU:
- 09347867
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
MSRP: $28.95Now: $26.06Was: $28.95 -
On Sale
COMETIC Top End Gasket Kit - 54.5 mm - Kawasaki C3543
COMETIC
MSRP: $31.95Now: $28.76Was: $31.95A quality top end gasket kit is critical to maintaining compression, preventing coolant and oil leaks, and ensuring reliable performance during high-output operation. The COMETIC C3543 is engineered...09347841- SKU:
- 09347841
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
MSRP: $31.95Now: $28.76Was: $31.95 -
On Sale
COMETIC Top End Gasket Kit - 77 mm - Yamaha C3549-EST
COMETIC
MSRP: $74.95Now: $67.46Was: $74.95A failing top end gasket compromises compression, kills power, and leaves you stranded. Cometic's EST gasket kit seals high-output 4-stroke engines reliably, whether naturally aspirated or boosted,...09347842- SKU:
- 09347842
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
MSRP: $74.95Now: $67.46Was: $74.95 -
On Sale
COMETIC Top End Gasket Kit - 79 mm - Honda C3635
COMETIC
MSRP: $67.95Now: $61.16Was: $67.95A quality top end gasket kit is critical for maintaining cylinder pressure and preventing catastrophic coolant or oil leaks—especially when running high-horsepower naturally aspirated or...09347846- SKU:
- 09347846
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
MSRP: $67.95Now: $61.16Was: $67.95 -
On Sale
COMETIC Top End Gasket Kit - 96 mm - Kawasaki C3696
COMETIC
MSRP: $85.95Now: $77.36Was: $85.95A failed head gasket means downtime and expensive engine damage—especially on high-output 4-stroke engines running elevated cylinder pressures. The COMETIC Top End Gasket Kit delivers the sealing...09347848- SKU:
- 09347848
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
MSRP: $85.95Now: $77.36Was: $85.95 -
On Sale
COMETIC Top End Gasket Kit - 96 mm - Honda C3733
COMETIC
MSRP: $85.95Now: $77.36Was: $85.95A failing top end gasket compromises combustion sealing and allows coolant or oil to escape—both catastrophic for engine reliability and performance. This COMETIC kit delivers OEM-correct fitment...09347850- SKU:
- 09347850
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
MSRP: $85.95Now: $77.36Was: $85.95 -
On Sale
COMETIC Top End Gasket Kit - KTM/Husqvarna/Gas Gas C3636
COMETIC
MSRP: $47.95Now: $43.16Was: $47.95A failed top-end gasket can cost you race time, engine damage, and thousands in repairs. The COMETIC C3636 kit delivers OEM-quality sealing with performance-grade materials engineered to handle the...09347801- SKU:
- 09347801
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
MSRP: $47.95Now: $43.16Was: $47.95 -
On Sale
COMETIC Top End Gasket Kit - 80 mm - Yamaha C3766
COMETIC
MSRP: $79.95Now: $71.96Was: $79.95A failing top-end gasket compromises combustion chamber sealing, killing power output and risking catastrophic engine damage. The COMETIC C3766 kit delivers the precision sealing your high-output...09347852- SKU:
- 09347852
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
MSRP: $79.95Now: $71.96Was: $79.95 -
On Sale
COMETIC Top End Gasket Kit - KTM/Husqvarna/Gas Gas C3811
COMETIC
MSRP: $79.95Now: $71.96Was: $79.95A failed top end gasket can sideline your bike and compromise engine integrity—especially when you're pushing high horsepower through naturally aspirated or forced induction setups. This Cometic kit...09347803- SKU:
- 09347803
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
MSRP: $79.95Now: $71.96Was: $79.95 -
On Sale
COMETIC Top End Gasket Kit - 91 mm - KTM C3784-EST
COMETIC
MSRP: $74.95Now: $67.46Was: $74.95A quality gasket kit is non-negotiable for any top-end rebuild—it's your seal against compression loss, coolant weeping, and catastrophic engine failure. The COMETIC C3784-EST delivers the sealing...09347854- SKU:
- 09347854
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
MSRP: $74.95Now: $67.46Was: $74.95 -
On Sale
COMETIC Top End Gasket Kit - 97 mm - Yamaha C3786
COMETIC
MSRP: $78.95Now: $71.06Was: $78.95A failing top end gasket will compromise combustion sealing and cost you power—or worse, create catastrophic engine damage. This Cometic kit delivers the complete solution with precision-engineered...09347855- SKU:
- 09347855
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
MSRP: $78.95Now: $71.06Was: $78.95 -
On Sale
COMETIC Top End Gasket Kit - 79 mm - Kawasaki C3787
COMETIC
MSRP: $84.95Now: $76.46Was: $84.95A failing head gasket will cost you power, reliability, and time on the track or in the shop. COMETIC's multi-layered steel design with Viton rubber coating distributes combustion pressure evenly...09347856- SKU:
- 09347856
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
MSRP: $84.95Now: $76.46Was: $84.95 -
On Sale
COMETIC Top End Gasket Kit - 95 mm - KTM/Husqvarna/Gas Gas C3604-EST
COMETIC
MSRP: $74.95Now: $67.46Was: $74.95A failing top end gasket compromises combustion sealing, kills power, and invites catastrophic engine damage. The COMETIC C3604-EST delivers OEM-spec sealing reliability with advanced multi-layer...09347807- SKU:
- 09347807
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
MSRP: $74.95Now: $67.46Was: $74.95 -
On Sale
COMETIC Top End Gasket Kit - 96 mm - Honda C3801
COMETIC
MSRP: $85.95Now: $77.36Was: $85.95A failed head gasket means catastrophic engine damage and costly downtime. The COMETIC Top End Gasket Kit delivers the sealing integrity and thermal management your high-output engine demands,...09347859- SKU:
- 09347859
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
MSRP: $85.95Now: $77.36Was: $85.95 -
On Sale
COMETIC Top End Gasket Kit - 88 mm - KTM/Husqvarna/Gas Gas C3810
COMETIC
MSRP: $102.95Now: $92.66Was: $102.95A top end gasket kit failure can mean catastrophic engine damage and costly downtime. Cometic's multi-layered design with EST (Extreme Sealing Technology) delivers superior heat dissipation and bore...09347862- SKU:
- 09347862
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
MSRP: $102.95Now: $92.66Was: $102.95Qty in Cart: 0Quantity:Price:MSRP: $102.95Now: $92.66Was: $102.95Subtotal: -
On Sale
COMETIC Top End Gasket Kit - 97 mm - Yamaha C3813
COMETIC
MSRP: $87.95Now: $79.16Was: $87.95A compromised top end gasket is one of the quickest ways to lose compression, power, and reliability. The COMETIC C3813 Top End Gasket Kit is engineered for high-output 4-stroke engines that demand...09347863- SKU:
- 09347863
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
MSRP: $87.95Now: $79.16Was: $87.95 -
On Sale
COMETIC Top End Gasket Kit - KTM C3818
COMETIC
MSRP: $47.95Now: $43.16Was: $47.95A quality top-end gasket kit is essential for maintaining cylinder pressure, preventing coolant leaks, and maximizing power output on high-performance 4-stroke engines. Cometic's EST (Extreme Sealing...09347864- SKU:
- 09347864
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
MSRP: $47.95Now: $43.16Was: $47.95Qty in Cart: 0Quantity:Price:MSRP: $47.95Now: $43.16Was: $47.95Subtotal:
