Select Your Ride

1
2
3

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 Head Gasket - .03" - Evo - 3.75" C9694 COMETIC Head Gasket - .03" - Evo - 3.75" C9694

    COMETIC Head Gasket - .03" - Evo - 3.75" C9694

    COMETIC

    $61.90
    A quality head gasket is critical to maintaining cylinder pressure, preventing coolant and oil leakage, and preserving engine reliability under boost or high RPM conditions. The COMETIC .03" MLS design uses Load Control Embossments to distribute clamping...
    09341353
    SKU:
    09341353
    Availability:
    Ships Same Business Day
    Weight:
    0.18 LBS
    MATERIAL:
    VITON
    RIDING STYLE:
    STREET
    THICKNESS METRIC:
    0.76 MM
    PRODUCT NAME:
    GASKET
    UNITS:
    PAIR
    BORE SIZE IMPERIAL:
    3.750'
    THICKNESS IMPERIAL:
    0,030'
    BORE SIZE:
    3,750'
    MATERIAL:
    LAYERED STEEL
    THICKNESS:
    0,76 MM (0,030')
    TYPE:
    CYLINDER HEAD
    Qty in Cart: 0
    Quantity:
    Price:
    $61.90
    Subtotal:
  • COMETIC Head Gasket -  .04" - 3 13/16" C9693

    COMETIC Head Gasket - .04" - 3 13/16" C9693

    COMETIC

    $61.90
    A head gasket failure will cost you far more in downtime and engine damage than the price of a quality replacement. The Cometic C9693 uses multi-layer steel construction with load control embossments to maintain consistent clamping force across the...
    09341356
    SKU:
    09341356
    Availability:
    Ships Same Business Day
    Weight:
    0.23 LBS
    PRODUCT NAME:
    GASKET
    THICKNESS:
    1,02 MM (0,040')
    BORE SIZE:
    3,8125'
    BORE SIZE IMPERIAL:
    3.8125'
    RIDING STYLE:
    STREET
    THICKNESS IMPERIAL:
    0,040'
    TYPE:
    CYLINDER HEAD
    MATERIAL:
    LAYERED STEEL
    UNITS:
    PAIR
    THICKNESS METRIC:
    1.02 MM
    $61.90
    Qty in Cart: 0
    Quantity:
    Price:
    $61.90
    Subtotal:
  • COMETIC Shift Sleeve O-Ring C9484

    COMETIC Shift Sleeve O-Ring C9484

    COMETIC

    $9.50
    Shift sleeve o-rings endure extreme heat, pressure, and fuel exposure during performance driving—and failure means transmission fluid leakage, loss of shift precision, and costly downtime. The COMETIC C9484 is engineered with fuel-resistant elastomer...
    09341372
    SKU:
    09341372
    Availability:
    Ships Same Business Day
    Weight:
    0.10 LBS
    MATERIAL:
    VITON
    RIDING STYLE:
    STREET
    UNITS:
    25 PACK
    PRODUCT NAME:
    O-RING
    APPLICATION:
    SHIFTER LEVER
    $9.50
    Qty in Cart: 0
    Quantity:
    Price:
    $9.50
    Subtotal:
  • COMETIC Rocker Gasket - .020" C9576

    COMETIC Rocker Gasket - .020" C9576

    COMETIC

    $62.70
    Rocker arm gaskets endure constant thermal cycling and high RPM loads—degradation here leads to oil seepage, reduced sealing integrity, and potential engine damage. The COMETIC C9576 delivers superior durability through its Viton elastomer construction,...
    09340750
    SKU:
    09340750
    Availability:
    Ships Same Business Day
    Weight:
    0.81 LBS
    RIDING STYLE:
    STREET
    THICKNESS IMPERIAL:
    0,020'
    TYPE:
    ROCKER BOX
    THICKNESS METRIC:
    0.51 MM
    MATERIAL:
    RUBBER
    MATERIAL:
    STEEL
    THICKNESS:
    0,51 MM (0,020')
    PRODUCT NAME:
    GASKET
    UNITS:
    10 PACK
    $62.70
    Qty in Cart: 0
    Quantity:
    Price:
    $62.70
    Subtotal:
  • COMETIC Primary Gasket C9943F5

    COMETIC Primary Gasket C9943F5

    COMETIC

    $83.50
    A primary gasket is critical to maintaining a sealed, leak-free engine case—especially under high RPM and boost conditions where pressure spikes demand absolute reliability. COMETIC's C9943F5 delivers the durability and precision fit that professional...
    09340747
    SKU:
    09340747
    Availability:
    Ships Same Business Day
    Weight:
    0.35 LBS
    THICKNESS IMPERIAL:
    0.060'
    TYPE:
    PRIMARY
    THICKNESS:
    1,52 MM (0,060')
    UNITS:
    5 PACK
    MOUNTING POSITION:
    OUTER
    RIDING STYLE:
    STREET
    THICKNESS METRIC:
    1.52 MM
    MATERIAL:
    AFM (ALUMINUM FOAM MATERIAL)
    PRODUCT NAME:
    GASKET
    $83.50
    Qty in Cart: 0
    Quantity:
    Price:
    $83.50
    Subtotal:
  • COMETIC Double Lip Seal C9350

    COMETIC Double Lip Seal C9350

    COMETIC

    $14.80
    A quality crankshaft seal is the difference between a clean engine bay and catastrophic oil leakage under sustained load. The COMETIC Double Lip Seal C9350 delivers the reliability you need for high-performance applications, engineered with premium...
    09350171
    SKU:
    09350171
    Availability:
    Ships Same Business Day
    Weight:
    0.10 LBS
    MATERIAL:
    VITON
    UNITS:
    5 PACK
    RIDING STYLE:
    STREET
    APPLICATION:
    CAM COVER
    PRODUCT NAME:
    SEAL
    $14.80
    Qty in Cart: 0
    Quantity:
    Price:
    $14.80
    Subtotal:
  • COMETIC Inspection Cover Gasket - FL C9305F5

    COMETIC Inspection Cover Gasket - FL C9305F5

    COMETIC

    $25.60
    A leaking inspection cover gasket compromises engine sealing and invites contaminant ingress—exactly what your engine doesn't need. The COMETIC C9305F5 delivers OEM-grade sealing integrity with the precision fit your application demands. Made in the U.S...
    20111494
    SKU:
    20111494
    Availability:
    Ships Same Business Day
    Weight:
    0.10 LBS
    RIDING STYLE:
    STREET
    THICKNESS METRIC:
    1.52 MM
    THICKNESS:
    1,52 MM (0,060')
    TYPE:
    INSPECTION COVER
    MATERIAL:
    AFM (ALUMINUM FOAM MATERIAL)
    UNITS:
    5 PACK
    PRODUCT NAME:
    GASKET
    THICKNESS IMPERIAL:
    0.060'
    Qty in Cart: 0
    Quantity:
    Price:
    $25.60
    Subtotal:
  • COMETIC O-Ring C10201

    COMETIC O-Ring C10201

    COMETIC

    $11.90
    Proper sealing is non-negotiable in high-performance engine builds, and a compromised O-ring can lead to costly leaks and catastrophic failures. The COMETIC C10201 delivers reliable, precision sealing for critical engine applications where margin for...
    09350990
    SKU:
    09350990
    Availability:
    Ships Same Business Day
    Weight:
    0.10 LBS
    PRODUCT NAME:
    O-RING
    APPLICATION:
    CYLINDER
    RIDING STYLE:
    ATV
    UNITS:
    10 PACK
    $11.90
    Qty in Cart: 0
    Quantity:
    Price:
    $11.90
    Subtotal:
  • COMETIC Primary Seal Kit C10248

    COMETIC Primary Seal Kit C10248

    COMETIC

    $86.05
    A primary seal kit is the foundation of a leak-free, reliable engine—and Cometic's AFM gasket material sets the standard for high-performance applications. Whether you're running a street engine or a race-prepped mill, this kit delivers the durability...
    09351031
    SKU:
    09351031
    Availability:
    Ships Same Business Day
    Weight:
    0.40 LBS
    RIDING STYLE:
    STREET
    MATERIAL:
    AFM (ALUMINUM FOAM MATERIAL)
    PRODUCT NAME:
    SEAL
    UNITS:
    KIT
    TYPE:
    PRIMARY
    $86.05
    Qty in Cart: 0
    Quantity:
    Price:
    $86.05
    Subtotal:
  • COMETIC Top End Gasket Twin Cam - EST C9976-030

    COMETIC Top End Gasket Twin Cam - EST C9976-030

    COMETIC

    $150.10
    A failed top-end gasket can sideline your engine and drain your wallet. The COMETIC EST C9976-030 eliminates guesswork by delivering a complete, purpose-built gasket kit engineered to handle sustained combustion pressures and thermal cycling without...
    09341663
    SKU:
    09341663
    Availability:
    Ships Same Business Day
    Weight:
    0.90 LBS
    RIDING STYLE:
    STREET
    THICKNESS IMPERIAL:
    0,020'
    THICKNESS IMPERIAL:
    0,030'
    TYPE:
    TOP END
    BORE SIZE:
    4,125'
    BORE SIZE IMPERIAL:
    4.125'
    THICKNESS METRIC:
    0.76 MM
    ENGINE TYPE:
    4-STROKE
    MATERIAL:
    STAINLESS STEEL
    PRODUCT NAME:
    GASKET KIT
    THICKNESS METRIC:
    0.51 MM
    MATERIAL:
    RUBBER
    UNITS:
    KIT
    $150.10
    Qty in Cart: 0
    Quantity:
    Price:
    $150.10
    Subtotal:
  • COMETIC Head Gasket - 4.000" x .030" C10084-030

    COMETIC Head Gasket - 4.000" x .030" C10084-030

    COMETIC

    $59.80
    A properly sealed combustion chamber is non-negotiable for consistent power delivery and engine longevity. COMETIC's MLS head gasket design minimizes bore distortion through load-control embossments, ensuring reliable sealing across demanding boost...
    09343147
    SKU:
    09343147
    Availability:
    Ships Same Business Day
    Weight:
    0.16 LBS
    BORE SIZE:
    4,000'
    MATERIAL:
    VITON
    BORE SIZE IMPERIAL:
    4.000'
    THICKNESS:
    0,76 MM (0,030')
    THICKNESS IMPERIAL:
    0,030'
    THICKNESS METRIC:
    0.76 MM
    PRODUCT NAME:
    GASKET
    RIDING STYLE:
    STREET
    UNITS:
    PAIR
    TYPE:
    CYLINDER HEAD
    $59.80
    Qty in Cart: 0
    Quantity:
    Price:
    $59.80
    Subtotal:
  • COMETIC Head Gasket - 4.060" x .030" C10085-030

    COMETIC Head Gasket - 4.060" x .030" C10085-030

    COMETIC

    $59.80
    A head gasket failure can cost you thousands in engine damage and lost track time. COMETIC's MLS design distributes clamping force evenly across the sealing surface, reducing bore distortion and maximizing ring seal for consistent power delivery. Built...
    09343149
    SKU:
    09343149
    Availability:
    Ships Same Business Day
    Weight:
    0.25 LBS
    BORE SIZE:
    4,060'
    MATERIAL:
    VITON
    PRODUCT NAME:
    GASKET
    RIDING STYLE:
    STREET
    THICKNESS:
    0,76 MM (0,030')
    THICKNESS METRIC:
    0.76 MM
    TYPE:
    CYLINDER HEAD
    UNITS:
    PAIR
    BORE SIZE IMPERIAL:
    4.060'
    THICKNESS IMPERIAL:
    0,030'
    $59.80
    Qty in Cart: 0
    Quantity:
    Price:
    $59.80
    Subtotal:
  • COMETIC Head Gasket - 4.125" x .040" C10086-040

    COMETIC Head Gasket - 4.125" x .040" C10086-040

    COMETIC

    $59.80
    A quality head gasket is the foundation of reliable cylinder sealing and consistent compression. The COMETIC C10086-040 delivers precision engineering with its multi-layer steel construction, designed to maintain a tight seal across demanding racing and...
    09343152
    SKU:
    09343152
    Availability:
    Ships Same Business Day
    Weight:
    0.25 LBS
    THICKNESS IMPERIAL:
    0,040'
    THICKNESS METRIC:
    1.02 MM
    MATERIAL:
    VITON
    BORE SIZE IMPERIAL:
    4.125'
    TYPE:
    CYLINDER HEAD
    BORE SIZE:
    4,125'
    PRODUCT NAME:
    GASKET
    RIDING STYLE:
    STREET
    THICKNESS:
    1,02 MM (0,040')
    UNITS:
    PAIR
    $59.80
    Qty in Cart: 0
    Quantity:
    Price:
    $59.80
    Subtotal:
  • COMETIC Top End Gasket Kit - Buell C10111

    COMETIC Top End Gasket Kit - Buell C10111

    COMETIC

    $142.75
    A top-end rebuild demands precision gaskets that can withstand extreme combustion pressures and thermal cycling without failure. The COMETIC C10111 kit eliminates the guesswork by delivering factory-spec gaskets engineered to manage heat distribution and...
    09344732
    SKU:
    09344732
    Availability:
    Ships Same Business Day
    Weight:
    0.60 LBS
    MATERIAL:
    VITON
    RIDING STYLE:
    STREET
    BORE SIZE:
    3,500'
    BORE SIZE IMPERIAL:
    3.500'
    MATERIAL:
    ALUMINUM
    PRODUCT NAME:
    GASKET KIT
    ENGINE TYPE:
    4-STROKE
    MATERIAL:
    RUBBER
    MATERIAL:
    STEEL
    TYPE:
    TOP END
    UNITS:
    KIT
    $142.75
    Qty in Cart: 0
    Quantity:
    Price:
    $142.75
    Subtotal:
  • COMETIC Primary Gasket C9309F5

    COMETIC Primary Gasket C9309F5

    COMETIC

    $120.50
    A primary gasket is critical to maintaining a sealed, leak-free crankcase in high-performance engines where internal pressures and temperature fluctuations demand absolute reliability. The COMETIC C9309F5 is engineered to withstand sustained RPM and...
    20111488
    SKU:
    20111488
    Availability:
    Ships Same Business Day
    Weight:
    0.44 LBS
    THICKNESS METRIC:
    1.52 MM
    UNITS:
    5 PACK
    MATERIAL:
    AFM (ALUMINUM FOAM MATERIAL)
    RIDING STYLE:
    STREET
    THICKNESS:
    1,52 MM (0,060')
    MOUNTING POSITION:
    OUTER
    PRODUCT NAME:
    GASKET
    THICKNESS IMPERIAL:
    0.060'
    TYPE:
    PRIMARY COVER
    $120.50
    Qty in Cart: 0
    Quantity:
    Price:
    $120.50
    Subtotal:
  • COMETIC Primary Gasket C9145F1

    COMETIC Primary Gasket C9145F1

    COMETIC

    $46.15
    Primary gasket failures compromise engine sealing and lead to costly leaks and performance loss. Cometic's AFM gasket technology delivers superior heat resistance and shape recovery, ensuring reliable sealing on high-output engines without requiring...
    09341205
    SKU:
    09341205
    Availability:
    Ships Same Business Day
    Weight:
    0.25 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')
    $46.15
    Qty in Cart: 0
    Quantity:
    Price:
    $46.15
    Subtotal:
  • COMETIC Exhaust Gasket - Tapered C9288

    COMETIC Exhaust Gasket - Tapered C9288

    COMETIC

    $38.00
    A failing exhaust gasket compromises both performance and reliability, allowing heat and pressure to escape where they shouldn't. The COMETIC C9288 tapered design seals precisely at the flange interface, eliminating leaks across the full operating range...
    09341337
    SKU:
    09341337
    Availability:
    Ships Same Business Day
    Weight:
    0.15 LBS
    PRODUCT NAME:
    GASKET
    MATERIAL:
    GRAPHITE
    RIDING STYLE:
    STREET
    MATERIAL:
    STAINLESS STEEL
    TYPE:
    EXHAUST
    UNITS:
    10 PACK
    Qty in Cart: 0
    Quantity:
    Price:
    $38.00
    Subtotal:
  • COMETIC Primary Gasket Kit C9889

    COMETIC Primary Gasket Kit C9889

    COMETIC

    $101.80
    A primary gasket kit failure means oil leaks, performance loss, and costly downtime. The COMETIC C9889 eliminates these risks with AFM gaskets engineered for extreme heat and pressure, delivering reliable sealing that holds torque cycle after cycle...
    09340744
    SKU:
    09340744
    Availability:
    Ships Same Business Day
    Weight:
    0.96 LBS
    PRODUCT NAME:
    GASKET KIT
    UNITS:
    KIT
    MATERIAL:
    AFM (ALUMINUM FOAM MATERIAL)
    RIDING STYLE:
    STREET
    TYPE:
    PRIMARY
    $101.80
    Qty in Cart: 0
    Quantity:
    Price:
    $101.80
    Subtotal:
  • FEULING OIL PUMP CORP. Chain Drive Cams - 525 Series - Twin Cam 1006

    FEULING OIL PUMP CORP. Chain Drive Cams - 525 Series - Twin Cam 1006

    FEULING OIL PUMP CORP.

    $399.95
    If you're running a stock or modified Twin Cam engine and want measurable gains in low-end torque and throttle response without a complete valve train overhaul, the Feuling 525 Series Chain Drive Cams deliver immediate, usable power where it matters most...
    09250427
    SKU:
    09250427
    Availability:
    Ships Same Business Day
    Weight:
    3.28 LBS
    APPLICATION:
    INTAKE
    EXHAUST CLOSE IMPERIAL:
    5°
    GRIND:
    525 SERIES
    INTAKE DURATION IMPERIAL:
    226°
    APPLICATION:
    EXHAUST
    EXHAUST OPEN IMPERIAL:
    51°
    INTAKE OPEN IMPERIAL:
    4°
    PRODUCT NAME:
    CAMSHAFT
    TYPE:
    CHAIN
    EXHAUST LIFT IMPERIAL:
    0.535'
    INTAKE CLOSE IMPERIAL:
    42°
    INTAKE LIFT IMPERIAL:
    0.525'
    MODEL:
    REAPER
    UNITS:
    PAIR
    EXHAUST DURATION IMPERIAL:
    236°
    RIDING STYLE:
    STREET
    $399.95
    Qty in Cart: 0
    Quantity:
    Price:
    $399.95
    Subtotal:
  • FEULING OIL PUMP CORP. Conversion Cams - 525 Series - Twin Cam 1016

    FEULING OIL PUMP CORP. Conversion Cams - 525 Series - Twin Cam 1016

    FEULING OIL PUMP CORP.

    $409.95
    If you're running a stock or mildly modified Twin Cam and want to unlock real-world power gains without a complete top-end overhaul, the Feuling 525 Series cams deliver where it counts. You'll feel the difference immediately—sharper throttle response,...
    09250606
    SKU:
    09250606
    Availability:
    Ships Same Business Day
    Weight:
    3.10 LBS
    APPLICATION:
    EXHAUST
    EXHAUST LIFT IMPERIAL:
    0.535'
    EXHAUST OPEN IMPERIAL:
    51°
    INTAKE CLOSE IMPERIAL:
    42°
    MODEL:
    REAPER
    APPLICATION:
    INTAKE
    EXHAUST CLOSE IMPERIAL:
    5°
    EXHAUST DURATION IMPERIAL:
    236°
    INTAKE DURATION IMPERIAL:
    226°
    RIDING STYLE:
    STREET
    TYPE:
    CHAIN CONVERSION
    GRIND:
    525 SERIES
    INTAKE LIFT IMPERIAL:
    0.525'
    INTAKE OPEN IMPERIAL:
    4°
    PRODUCT NAME:
    CAMSHAFT
    UNITS:
    PAIR
    $409.95
    Qty in Cart: 0
    Quantity:
    Price:
    $409.95
    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

SECURE & SAFE PAYMENT

EASY RETURNS

FAST DELIVERY

AUTHORIZED DEALER