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Harley Engine

Harley Engine

Harley Engine

Harley Bike Engine Parts at JJ Motorsports

Rebuild and boost your Harley's engine with premium parts from JJ Motorsports. Our inventory features complete gasket sets, piston kits, oil filters, pushrod tubes, and coolers designed for maximum strength, leak-free sealing, and high-performance in extreme conditions. Compatible with Big Twins, Softail, Touring, and more, these components support top-end overhauls, oil management, and durability for street rides or custom builds.

Shop trusted brands like Drag Specialties for magnetic filters and Wiseco for forged pistons. Explore related categories such as Harley air and fuel for carb tuning or Harley drivetrain for transmission upgrades.

Top Harley Engine Products

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
  • COMETIC Air Cleaner Gasket C9301

    COMETIC Air Cleaner Gasket C9301

    COMETIC

    $13.30
    A worn or damaged air cleaner gasket compromises your engine's intake seal, allowing unfiltered air to bypass your filter element and introducing contaminants directly into the combustion chamber. The COMETIC C9301 restores that critical seal with...
    09341394
    SKU:
    09341394
    Availability:
    Ships Same Business Day
    Weight:
    0.13 LBS
    RIDING STYLE:
    STREET
    UNITS:
    20 PACK
    PRODUCT NAME:
    GASKET
    TYPE:
    AIR CLEANER
    $13.30
    Qty in Cart: 0
    Quantity:
    Price:
    $13.30
    Subtotal:
  • COMETIC Outer Rocker Gasket C9196

    COMETIC Outer Rocker Gasket C9196

    COMETIC

    $23.10
    Rocker cover gaskets endure constant thermal cycling and oil exposure—factory gaskets fail prematurely under sustained engine loads. The COMETIC C9196 delivers reliable sealing with a dual-layer Viton design that resists oil degradation and maintains...
    09341395
    SKU:
    09341395
    Availability:
    Ships Same Business Day
    Weight:
    0.06 LBS
    RIDING STYLE:
    STREET
    MATERIAL:
    SILICONE
    PRODUCT NAME:
    GASKET
    UNITS:
    PAIR
    MOUNTING POSITION:
    LOWER
    MOUNTING POSITION:
    OUTER
    TYPE:
    ROCKER COVER
    $23.10
    Qty in Cart: 0
    Quantity:
    Price:
    $23.10
    Subtotal:
  • COMETIC Rocker Breather Seal C9198

    COMETIC Rocker Breather Seal C9198

    COMETIC

    $9.40
    Crankcase pressure management directly impacts engine reliability and longevity. The COMETIC Rocker Breather Seal C9198 prevents oil seepage and maintains proper ventilation in your rocker cover assembly, eliminating messy leaks that compromise engine...
    09341397
    SKU:
    09341397
    Availability:
    Ships Same Business Day
    Weight:
    0.05 LBS
    RIDING STYLE:
    STREET
    PRODUCT NAME:
    SEAL
    APPLICATION:
    ROCKER COVER
    MATERIAL:
    SILICONE
    UNITS:
    PAIR
    $9.40
    Qty in Cart: 0
    Quantity:
    Price:
    $9.40
    Subtotal:
  • On Sale
    COMETIC Top End Gasket - XL 1200 C9177

    COMETIC Top End Gasket - XL 1200 C9177

    COMETIC

    MSRP: $149.89
    Now: $134.00
    Was: $149.89
    Top-end gasket failure can sideline your engine at the worst possible moment—Cometic's EST (Extreme Sealing Technology) gasket kit eliminates the guesswork with precision-engineered components designed to maintain a reliable seal under the extreme heat...
    09341225
    SKU:
    09341225
    Availability:
    Ships Same Business Day
    Weight:
    0.50 LBS
    BORE SIZE:
    3,500'
    BORE SIZE IMPERIAL:
    3.500'
    TYPE:
    TOP END
    DISPLACEMENT:
    1200 CC
    MATERIAL:
    RUBBER
    MATERIAL:
    STAINLESS STEEL
    RIDING STYLE:
    STREET
    THICKNESS IMPERIAL:
    0,040'
    THICKNESS METRIC:
    1.02 MM
    ENGINE TYPE:
    4-STROKE
    PRODUCT NAME:
    GASKET KIT
    UNITS:
    KIT
    MSRP: $149.89
    Now: $134.00
    Was: $149.89
    Qty in Cart: 0
    Quantity:
    Price:
    MSRP: $149.89
    Now: $134.00
    Was: $149.89
    Subtotal:
  • On Sale
    COMETIC Primary Gasket C9179F1

    COMETIC Primary Gasket C9179F1

    COMETIC

    MSRP: $48.46
    Now: $43.00
    Was: $48.46
    A primary gasket kit is only as reliable as its ability to seal under extreme heat and pressure—and the COMETIC C9179F1 delivers where it counts. Built with Cometic's AFM (Aluminum Foamette Material) technology, this gasket maintains a rock-solid seal...
    09341226
    SKU:
    09341226
    Availability:
    Ships Same Business Day
    Weight:
    0.40 LBS
    THICKNESS IMPERIAL:
    0.060'
    TYPE:
    PRIMARY
    MATERIAL:
    AFM (ALUMINUM FOAM MATERIAL)
    PRODUCT NAME:
    GASKET
    UNITS:
    EACH
    MOUNTING POSITION:
    OUTER
    RIDING STYLE:
    STREET
    THICKNESS METRIC:
    1.52 MM
    THICKNESS:
    1,52 MM (0,060')
    MSRP: $48.46
    Now: $43.00
    Was: $48.46
    Qty in Cart: 0
    Quantity:
    Price:
    MSRP: $48.46
    Now: $43.00
    Was: $48.46
    Subtotal:
  • On Sale
    COMETIC Complete Gasket Kit - FL 103 C9185

    COMETIC Complete Gasket Kit - FL 103 C9185

    COMETIC

    MSRP: $302.03
    Now: $270.00
    Was: $302.03
    A complete gasket kit is insurance against combustion leaks, oil seepage, and catastrophic engine failure. The COMETIC FL 103 C9185 eliminates the guesswork of sourcing individual gaskets by delivering every seal your engine needs in one comprehensive...
    09341230
    SKU:
    09341230
    Availability:
    Ships Same Business Day
    Weight:
    1.70 LBS
    RIDING STYLE:
    STREET
    BORE SIZE IMPERIAL:
    3.875'
    MATERIAL:
    AFM (ALUMINUM FOAM MATERIAL)
    PRODUCT NAME:
    GASKET KIT
    UNITS:
    KIT
    BORE SIZE:
    3,875'
    MATERIAL:
    VITON
    TYPE:
    COMPLETE
    MATERIAL:
    STEEL
    MSRP: $302.03
    Now: $270.00
    Was: $302.03
    Qty in Cart: 0
    Quantity:
    Price:
    MSRP: $302.03
    Now: $270.00
    Was: $302.03
    Subtotal:
  • On Sale
    COMETIC Complete Gasket Kit - Dyna C9186

    COMETIC Complete Gasket Kit - Dyna C9186

    COMETIC

    MSRP: $302.03
    Now: $270.00
    Was: $302.03
    A complete gasket kit eliminates the guesswork and risk of mixing incompatible gasket materials across your engine bay. COMETIC's C9186 uses purpose-built materials for each gasket application—MLS head gaskets for cylinder sealing, Viton coatings for oil...
    09341231
    SKU:
    09341231
    Availability:
    Ships Same Business Day
    Weight:
    1.65 LBS
    PRODUCT NAME:
    GASKET KIT
    BORE SIZE:
    3,875'
    MATERIAL:
    VITON
    TYPE:
    COMPLETE
    BORE SIZE IMPERIAL:
    3.875'
    MATERIAL:
    AFM (ALUMINUM FOAM MATERIAL)
    RIDING STYLE:
    STREET
    MATERIAL:
    STEEL
    UNITS:
    KIT
    MSRP: $302.03
    Now: $270.00
    Was: $302.03
    Qty in Cart: 0
    Quantity:
    Price:
    MSRP: $302.03
    Now: $270.00
    Was: $302.03
    Subtotal:
  • On Sale
    COMETIC Trans End Cover Gasket - Twin Cam C9188

    COMETIC Trans End Cover Gasket - Twin Cam C9188

    COMETIC

    Now: $19.00
    Was: $19.90
    A failing transmission end cover gasket can lead to costly fluid leaks and contamination that compromise your entire drivetrain. The COMETIC C9188 eliminates guesswork with a precision-engineered gasket that seals reliably without additional sealant,...
    09341233
    SKU:
    09341233
    Availability:
    Ships Same Business Day
    Weight:
    0.14 LBS
    THICKNESS:
    1,52 MM (0,060')
    PRODUCT NAME:
    GASKET
    THICKNESS IMPERIAL:
    0.060'
    UNITS:
    10 PACK
    MATERIAL:
    AFM (ALUMINUM FOAM MATERIAL)
    RIDING STYLE:
    STREET
    TYPE:
    END COVER
    THICKNESS METRIC:
    1.52 MM
    TYPE:
    CLUTCH RELEASE
    Now: $19.00
    Was: $19.90
    Qty in Cart: 0
    Quantity:
    Price:
    Now: $19.00
    Was: $19.90
    Subtotal:
  • On Sale
    COMETIC Transmission Top Cover Gasket Cover - Twin Cam C9189

    COMETIC Transmission Top Cover Gasket Cover - Twin Cam C9189

    COMETIC

    Now: $17.00
    Was: $18.50
    A leaking transmission cover gasket compromises both performance and reliability—and replacement gaskets that require messy sealer applications add unnecessary labor time. The COMETIC C9189 Transmission Top Cover Gasket eliminates that hassle with its...
    09341234
    SKU:
    09341234
    Availability:
    Ships Same Business Day
    Weight:
    0.27 LBS
    UNITS:
    10 PACK
    RIDING STYLE:
    STREET
    THICKNESS METRIC:
    1.52 MM
    MATERIAL:
    AFM (ALUMINUM FOAM MATERIAL)
    PRODUCT NAME:
    GASKET
    THICKNESS IMPERIAL:
    0.060'
    TYPE:
    TRANSMISSION TOP COVER
    THICKNESS:
    1,52 MM (0,060')
    Now: $17.00
    Was: $18.50
    Qty in Cart: 0
    Quantity:
    Price:
    Now: $17.00
    Was: $18.50
    Subtotal:
  • On Sale
    COMETIC Rocker Box Kit - XL C9195

    COMETIC Rocker Box Kit - XL C9195

    COMETIC

    MSRP: $68.30
    Now: $61.00
    Was: $68.30
    Rocker box failures can sideline your engine and drain your wallet. The COMETIC Rocker Box Kit C9195 eliminates downtime by providing all the premium gaskets, seals, and O-rings you need for a complete, reliable service on both rocker boxes. Built with...
    09341236
    SKU:
    09341236
    Availability:
    Ships Same Business Day
    Weight:
    0.38 LBS
    MATERIAL:
    STEEL
    MODEL:
    EST
    PRODUCT NAME:
    GASKET KIT
    UNITS:
    KIT
    RIDING STYLE:
    STREET
    TYPE:
    ROCKER BOX
    MSRP: $68.30
    Now: $61.00
    Was: $68.30
    Qty in Cart: 0
    Quantity:
    Price:
    MSRP: $68.30
    Now: $61.00
    Was: $68.30
    Subtotal:
  • On Sale
    COMETIC Exhaust Gasket - EVO/Twin Cam C9540

    COMETIC Exhaust Gasket - EVO/Twin Cam C9540

    COMETIC

    Now: $56.00
    Was: $59.20
    Exhaust gasket failure leads to costly leaks, performance loss, and potential engine damage—especially under high heat and boost conditions. The COMETIC C9540 eliminates these risks with a dual-layer construction designed to withstand extreme...
    09341237
    SKU:
    09341237
    Availability:
    Ships Same Business Day
    Weight:
    0.15 LBS
    PRODUCT NAME:
    GASKET
    TYPE:
    EXHAUST PORT
    RIDING STYLE:
    STREET
    MATERIAL:
    GRAPHITE
    MATERIAL:
    STAINLESS STEEL
    UNITS:
    10 PACK
    Now: $56.00
    Was: $59.20
    Qty in Cart: 0
    Quantity:
    Price:
    Now: $56.00
    Was: $59.20
    Subtotal:
  • On Sale
    COMETIC Exhaust Gasket - VROD C9928

    COMETIC Exhaust Gasket - VROD C9928

    COMETIC

    MSRP: $16.75
    Now: $15.00
    Was: $16.75
    Exhaust gasket failure is a common source of leaks that compromise performance and create costly complications down the line. The COMETIC C9928 is engineered to withstand extreme exhaust temperatures and the punishment of high-horsepower applications,...
    09341239
    SKU:
    09341239
    Availability:
    Ships Same Business Day
    Weight:
    0.06 LBS
    UNITS:
    PAIR
    PRODUCT NAME:
    GASKET
    MATERIAL:
    GRAPHITE
    RIDING STYLE:
    STREET
    TYPE:
    EXHAUST
    MSRP: $16.75
    Now: $15.00
    Was: $16.75
    Qty in Cart: 0
    Quantity:
    Price:
    MSRP: $16.75
    Now: $15.00
    Was: $16.75
    Subtotal:
  • On Sale
    COMETIC Complete Gasket Kit - FLT C9778F

    COMETIC Complete Gasket Kit - FLT C9778F

    COMETIC

    MSRP: $296.52
    Now: $265.00
    Was: $296.52
    A complete gasket kit eliminates the guesswork when rebuilding or refreshing your engine—you get every seal you need in one package, engineered to handle both street and race applications. Cometic's use of Multi-Layer Steel head gaskets and Viton-coated...
    09340728
    SKU:
    09340728
    Availability:
    Ships Same Business Day
    Weight:
    1.70 LBS
    TYPE:
    COMPLETE
    UNITS:
    KIT
    BORE SIZE:
    3,750'
    MATERIAL:
    AFM (ALUMINUM FOAM MATERIAL)
    PRODUCT NAME:
    GASKET KIT
    BORE SIZE IMPERIAL:
    3.750'
    MATERIAL:
    STEEL
    MATERIAL:
    VITON
    RIDING STYLE:
    STREET
    MSRP: $296.52
    Now: $265.00
    Was: $296.52
    Qty in Cart: 0
    Quantity:
    Price:
    MSRP: $296.52
    Now: $265.00
    Was: $296.52
    Subtotal:
  • On Sale
    COMETIC Complete Gasket - Softail/FXD C9751F

    COMETIC Complete Gasket - Softail/FXD C9751F

    COMETIC

    MSRP: $374.80
    Now: $336.00
    Was: $374.80
    A complete gasket failure can cost you a race—or worse, leave you stranded with a seized engine. The COMETIC Complete Gasket Kit for Softail/FXD eliminates guesswork by providing every critical seal your engine needs, engineered with purpose-built...
    09340730
    SKU:
    09340730
    Availability:
    Ships Same Business Day
    Weight:
    1.70 LBS
    RIDING STYLE:
    STREET
    THICKNESS IMPERIAL:
    0,040'
    THICKNESS METRIC:
    1.02 MM
    BORE SIZE:
    3,500'
    MATERIAL:
    AFM (ALUMINUM FOAM MATERIAL)
    PRODUCT NAME:
    GASKET KIT
    MATERIAL:
    STEEL
    MATERIAL:
    VITON
    BORE SIZE IMPERIAL:
    3.500'
    TYPE:
    COMPLETE
    UNITS:
    KIT
    MSRP: $374.80
    Now: $336.00
    Was: $374.80
    Qty in Cart: 0
    Quantity:
    Price:
    MSRP: $374.80
    Now: $336.00
    Was: $374.80
    Subtotal:
  • On Sale
    COMETIC Motor Gasket Kit - Standard - EVO C9891

    COMETIC Motor Gasket Kit - Standard - EVO C9891

    COMETIC

    MSRP: $192.88
    Now: $173.00
    Was: $192.88
    A complete gasket failure can end your race day—or worse, cost you an engine. The COMETIC Motor Gasket Kit C9891 delivers OEM-quality sealing across all critical engine surfaces, using race-proven materials that maintain their integrity under extreme...
    09340732
    SKU:
    09340732
    Availability:
    Ships Same Business Day
    Weight:
    1.67 LBS
    MATERIAL:
    AFM (ALUMINUM FOAM MATERIAL)
    RIDING STYLE:
    STREET
    BORE SIZE:
    3,500'
    BORE SIZE IMPERIAL:
    3.500'
    PRODUCT NAME:
    GASKET KIT
    MATERIAL:
    STEEL
    TYPE:
    MOTOR
    UNITS:
    KIT
    MSRP: $192.88
    Now: $173.00
    Was: $192.88
    Qty in Cart: 0
    Quantity:
    Price:
    MSRP: $192.88
    Now: $173.00
    Was: $192.88
    Subtotal:
  • On Sale
    COMETIC Motor Gasket Kit - Standard - EVO C9890

    COMETIC Motor Gasket Kit - Standard - EVO C9890

    COMETIC

    MSRP: $167.53
    Now: $150.00
    Was: $167.53
    A complete gasket failure can sideline your engine and compromise every component downstream. The COMETIC Motor Gasket Kit – Standard (C9890) delivers OEM-quality sealing across your entire engine using premium materials engineered to handle sustained...
    09340733
    SKU:
    09340733
    Availability:
    Ships Same Business Day
    Weight:
    1.67 LBS
    MATERIAL:
    STEEL
    PRODUCT NAME:
    GASKET KIT
    TYPE:
    MOTOR
    BORE SIZE:
    3,500'
    BORE SIZE IMPERIAL:
    3.500'
    UNITS:
    KIT
    MATERIAL:
    AFM (ALUMINUM FOAM MATERIAL)
    RIDING STYLE:
    STREET
    MSRP: $167.53
    Now: $150.00
    Was: $167.53
    Qty in Cart: 0
    Quantity:
    Price:
    MSRP: $167.53
    Now: $150.00
    Was: $167.53
    Subtotal:
  • On Sale
    COMETIC Complete Gasket Kit - Standard - XB9 C9857

    COMETIC Complete Gasket Kit - Standard - XB9 C9857

    COMETIC

    MSRP: $212.73
    Now: $190.00
    Was: $212.73
    A complete gasket failure can leave you stranded—or worse, cost you a race. The COMETIC Complete Gasket Kit C9857 eliminates guesswork by providing every gasket your XB9 engine needs, engineered with premium materials proven to handle sustained...
    09340734
    SKU:
    09340734
    Availability:
    Ships Same Business Day
    Weight:
    1.75 LBS
    BORE SIZE IMPERIAL:
    STANDARD
    MATERIAL:
    STEEL
    PRODUCT NAME:
    GASKET KIT
    TYPE:
    COMPLETE
    BORE SIZE:
    STANDARD
    RIDING STYLE:
    STREET
    UNITS:
    KIT
    MATERIAL:
    AFM (ALUMINUM FOAM MATERIAL)
    MATERIAL:
    VITON
    MSRP: $212.73
    Now: $190.00
    Was: $212.73
    Qty in Cart: 0
    Quantity:
    Price:
    MSRP: $212.73
    Now: $190.00
    Was: $212.73
    Subtotal:
  • On Sale
    COMETIC Motor Gasket Kit - XL - .030" C9953

    COMETIC Motor Gasket Kit - XL - .030" C9953

    COMETIC

    MSRP: $212.73
    Now: $190.00
    Was: $212.73
    A complete gasket failure can sideline your engine and drain your wallet. The COMETIC Motor Gasket Kit XL delivers OEM-quality sealing with race-grade materials engineered to handle high boost, extreme cylinder pressures, and sustained performance...
    09340735
    SKU:
    09340735
    Availability:
    Ships Same Business Day
    Weight:
    1.45 LBS
    MATERIAL:
    STEEL
    PRODUCT NAME:
    GASKET KIT
    THICKNESS IMPERIAL:
    0,030'
    BORE SIZE IMPERIAL:
    3.500'
    TYPE:
    COMPLETE
    UNITS:
    KIT
    RIDING STYLE:
    STREET
    BORE SIZE:
    3,500'
    MATERIAL:
    AFM (ALUMINUM FOAM MATERIAL)
    MATERIAL:
    VITON
    THICKNESS METRIC:
    0.76 MM
    MSRP: $212.73
    Now: $190.00
    Was: $212.73
    Qty in Cart: 0
    Quantity:
    Price:
    MSRP: $212.73
    Now: $190.00
    Was: $212.73
    Subtotal:
  • On Sale
    COMETIC Oil Jet Gasket - XL C9962

    COMETIC Oil Jet Gasket - XL C9962

    COMETIC

    Now: $8.00
    Was: $8.50
    Oil jet gaskets are critical sealing components in high-performance engines where precision oiling systems deliver fuel and coolant directly to combustion chambers and bearing surfaces. The COMETIC C9962 XL Oil Jet Gasket ensures a leak-free seal under...
    09340737
    SKU:
    09340737
    Availability:
    Ships Same Business Day
    Weight:
    0.10 LBS
    RIDING STYLE:
    STREET
    THICKNESS IMPERIAL:
    0,020'
    THICKNESS METRIC:
    0.51 MM
    UNITS:
    6 PACK
    MATERIAL:
    FIBER
    PRODUCT NAME:
    GASKET
    THICKNESS:
    0,51 MM (0,020')
    TYPE:
    OIL JET ASSEMBLY
    Qty in Cart: 0
    Quantity:
    Price:
    Now: $8.00
    Was: $8.50
    Subtotal:
  • On Sale
    COMETIC Top End Gasket -.045" C9951

    COMETIC Top End Gasket -.045" C9951

    COMETIC

    MSRP: $157.60
    Now: $141.00
    Was: $157.60
    Top-end gasket failure doesn't just waste your time—it compromises engine reliability and performance when you need it most. The COMETIC C9951 EST gasket kit eliminates thermal hot spots that lead to premature failure, keeping your combustion chamber...
    09340755
    SKU:
    09340755
    Availability:
    Ships Same Business Day
    Weight:
    0.78 LBS
    THICKNESS IMPERIAL:
    0,045'
    THICKNESS METRIC:
    1.14 MM
    TYPE:
    TOP END
    BORE SIZE:
    3,875'
    MATERIAL:
    RUBBER
    UNITS:
    KIT
    DISPLACEMENT:
    95'
    MATERIAL:
    STAINLESS STEEL
    PRODUCT NAME:
    GASKET KIT
    BORE SIZE IMPERIAL:
    3.875'
    ENGINE TYPE:
    4-STROKE
    RIDING STYLE:
    STREET
    MSRP: $157.60
    Now: $141.00
    Was: $157.60
    Qty in Cart: 0
    Quantity:
    Price:
    MSRP: $157.60
    Now: $141.00
    Was: $157.60
    Subtotal:
  • Total: items /

Adding your products to cart

Big Power, Nice Sound!

Picked up a Pro Circuit pipe and silencer for my YZ125 it’s a game changer. The power feels way better and the sound is awesome.

Tyler D. - 06/12

Perfect Fit

First time ordering here and dang y’all knocked it outta the park! The wheels fit my Ranger UTV perfect, and I’ll definitely be back for more 5 stars all day!

Sarah L. - 08/24

Fast Shipping!!

Ordered on a Monday, and it was on my doorstep by Wednesday! Super impressed with how fast the shipping was.

Jason P. - 09/13

Helps keep cool, works great!

Bought the dual pass Allstar radiator for my build, and it’s been solid. Keeps the engine running cool even on the hottest days no complaints here!

Jake M. - 05/21

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