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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On Sale
COMETIC Top End Gasket Kit - 97 mm - Suzuki C3233-EST
COMETIC
MSRP: $89.95Now: $85.00Was: $89.95Top End Gasket Kit - 97 mm - Suzuki Top end gasket kit includes correct base, head gasket and cylinder O-rings as well as other top end specific O-rings or seals needed for R&R of top end, MLS head gaskets promote an even torque load across the...09347827- SKU:
- 09347827
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
MSRP: $89.95Now: $85.00Was: $89.95 -
On Sale
COMETIC Top End Gasket Kit - 99 mm - Suzuki C3234-EST
COMETIC
MSRP: $89.95Now: $85.00Was: $89.95Top End Gasket Kit - 99 mm - Suzuki Top end gasket kit includes correct base, head gasket and cylinder O-rings as well as other top end specific O-rings or seals needed for R&R of top end, MLS head gaskets promote an even torque load across the...09347828- SKU:
- 09347828
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
MSRP: $89.95Now: $85.00Was: $89.95 -
On Sale
COMETIC Top End Gasket Kit - 101 mm - Suzuki C3235-EST
COMETIC
MSRP: $89.95Now: $85.00Was: $89.95Top End Gasket Kit - 101 mm - Suzuki Top end gasket kit includes correct base, head gasket and cylinder O-rings as well as other top end specific O-rings or seals needed for R&R of top end, MLS head gaskets promote an even torque load across the...09347831- SKU:
- 09347831
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
MSRP: $89.95Now: $85.00Was: $89.95 -
On Sale
COMETIC Top End Gasket Kit - 77 mm - Suzuki C3406-EST
COMETIC
MSRP: $69.95Now: $66.00Was: $69.95Top End Gasket Kit - 77 mm - Suzuki Top end gasket kit includes correct base, head gasket and cylinder O-rings as well as other top end specific O-rings or seals needed for R&R of top end, MLS head gaskets promote an even torque load across the...09347832- SKU:
- 09347832
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
MSRP: $69.95Now: $66.00Was: $69.95 -
On Sale
COMETIC Top End Gasket Kit - 79 mm - Suzuki C3407-EST
COMETIC
MSRP: $69.95Now: $66.00Was: $69.95Top End Gasket Kit - 79 mm - Suzuki Top end gasket kit includes correct base, head gasket and cylinder O-rings as well as other top end specific O-rings or seals needed for R&R of top end, MLS head gaskets promote an even torque load across the...09347833- SKU:
- 09347833
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
MSRP: $69.95Now: $66.00Was: $69.95 -
On Sale
COMETIC Top End Gasket Kit - 80 mm - Suzuki C3408-EST
COMETIC
MSRP: $69.95Now: $66.00Was: $69.95Top End Gasket Kit - 80 mm - Suzuki Top end gasket kit includes correct base, head gasket and cylinder O-rings as well as other top end specific O-rings or seals needed for R&R of top end, MLS head gaskets promote an even torque load across the...09347834- SKU:
- 09347834
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
MSRP: $69.95Now: $66.00Was: $69.95 -
On Sale
COMETIC Top End Gasket Kit - 82 mm - Suzuki C3409-EST
COMETIC
MSRP: $69.95Now: $66.00Was: $69.95Top End Gasket Kit - 82 mm - Suzuki Top end gasket kit includes correct base, head gasket and cylinder O-rings as well as other top end specific O-rings or seals needed for R&R of top end, MLS head gaskets promote an even torque load across the...09347836- SKU:
- 09347836
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
MSRP: $69.95Now: $66.00Was: $69.95 -
On Sale
COMETIC Top End Gasket Kit - 84 mm - Suzuki C3410-EST
COMETIC
MSRP: $69.95Now: $66.00Was: $69.95Top End Gasket Kit - 84 mm - Suzuki Top end gasket kit includes correct base, head gasket and cylinder O-rings as well as other top end specific O-rings or seals needed for R&R of top end, MLS head gaskets promote an even torque load across the...09347837- SKU:
- 09347837
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
MSRP: $69.95Now: $66.00Was: $69.95 -
On Sale
COMETIC Top End Gasket Kit - 97 mm - Yamaha C3540-EST
COMETIC
MSRP: $68.95Now: $65.00Was: $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
MSRP: $68.95Now: $65.00Was: $68.95 -
On Sale
COMETIC Top End Gasket Kit - 52.5 mm - Kawasaki C3542
COMETIC
MSRP: $31.95Now: $30.00Was: $31.95Top End Gasket Kit - 52.5 mm - Kawasaki Top end gasket kit includes correct base, head gasket and cylinder O-rings as well as other top end specific O-rings or seals needed for R&R of top end, MLS head gaskets promote an even torque load across the...09347840- SKU:
- 09347840
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
MSRP: $31.95Now: $30.00Was: $31.95 -
On Sale
COMETIC Top End Gasket Kit - 88 mm - KTM C3605-EST
COMETIC
MSRP: $74.95Now: $70.00Was: $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
MSRP: $74.95Now: $70.00Was: $74.95 -
On Sale
COMETIC Top End Gasket Kit - 96 mm - Honda C3621
COMETIC
MSRP: $85.95Now: $81.00Was: $85.95Top End Gasket Kit - 96 mm - Honda Top end gasket kit includes correct base, head gasket and cylinder O-rings as well as other top end specific O-rings or seals needed for R&R of top end, MLS head gaskets promote an even torque load across the gasket...09347844- SKU:
- 09347844
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
MSRP: $85.95Now: $81.00Was: $85.95 -
On Sale
COMETIC Top End Gasket Kit - 97 mm - Yamaha C3630
COMETIC
MSRP: $53.95Now: $51.00Was: $53.95Top End Gasket Kit - 97 mm - Yamaha Top end gasket kit includes correct base, head gasket and cylinder O-rings as well as other top end specific O-rings or seals needed for R&R of top end, MLS head gaskets promote an even torque load across the...09347845- SKU:
- 09347845
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
MSRP: $53.95Now: $51.00Was: $53.95 -
On Sale
COMETIC Top End Gasket Kit - 77 mm - Yamaha C3695
COMETIC
MSRP: $79.95Now: $75.00Was: $79.95Top End Gasket Kit - 77 mm - Yamaha Top end gasket kit includes correct base, head gasket and cylinder O-rings as well as other top end specific O-rings or seals needed for R&R of top end, MLS head gaskets promote an even torque load across the...09347847- SKU:
- 09347847
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
MSRP: $79.95Now: $75.00Was: $79.95 -
On Sale
COMETIC Top End Gasket Kit/O-Ring Cylinder Head Gasket - Yamaha C3731
COMETIC
MSRP: $39.95Now: $38.00Was: $39.95Top End Gasket Kit/O-Ring Cylinder Head Gasket - Yamaha Top-end gasket kit includes correct base, head gasket and cylinder O-rings as well as other top-end specific O-rings or seals needed for R&R of top end, Materials will vary depending on what is...09347849- SKU:
- 09347849
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
MSRP: $39.95Now: $38.00Was: $39.95 -
On Sale
COMETIC Top End Gasket Kit - 82 mm - Honda C3735
COMETIC
MSRP: $67.95Now: $64.00Was: $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
MSRP: $67.95Now: $64.00Was: $67.95 -
On Sale
COMETIC Top End Gasket Kit - KTM/Husqvarna C3808
COMETIC
MSRP: $92.95Now: $87.00Was: $92.95Top End Gasket Kit - KTM/Husqvarna Top end gasket kit includes correct base, head gasket and cylinder O-rings as well as other top end specific O-rings or seals needed for R&R of top end, MLS head gaskets promote an even torque load across the gasket...09347802- SKU:
- 09347802
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
MSRP: $92.95Now: $87.00Was: $92.95 -
On Sale
COMETIC Top End Gasket Kit - 90 mm - KTM C3779-EST
COMETIC
MSRP: $74.95Now: $70.00Was: $74.95Top End Gasket Kit - 90 mm - KTM Top end gasket kit includes correct base, head gasket and cylinder O-rings as well as other top end specific O-rings or seals needed for R&R of top end, MLS head gaskets promote an even torque load across the gasket...09347853- SKU:
- 09347853
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
MSRP: $74.95Now: $70.00Was: $74.95 -
On Sale
COMETIC Top End Gasket Kit - KTM/Husqvarna/Gas Gas C3623
COMETIC
MSRP: $46.95Now: $44.00Was: $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
MSRP: $46.95Now: $44.00Was: $46.95 -
On Sale
COMETIC Top End Gasket Kit - 79 mm - KTM/Husqvarna/Gas Gas C3595-EST
COMETIC
MSRP: $87.95Now: $83.00Was: $87.95Top End Gasket Kit - 79 mm - KTM/Husqvarna/Gas Gas Top end gasket kit includes correct base, head gasket and cylinder O-rings as well as other top end specific O-rings or seals needed for R&R of top end, MLS head gaskets promote an even torque load...09347806- SKU:
- 09347806
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
MSRP: $87.95Now: $83.00Was: $87.95
