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 Air Cleaner Gasket C9301

    COMETIC Air Cleaner Gasket C9301

    COMETIC

    $13.30
    Made in the U.S.A.
    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

    $22.00
    Viton gaskets feature a stainless steel core with a .001"-thick coating of Viton rubber on both sides., Made in the U.S.A.
    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
    $22.00
    Qty in Cart: 0
    Quantity:
    Price:
    $22.00
    Subtotal:
  • COMETIC Rocker Breather Seal C9198

    COMETIC Rocker Breather Seal C9198

    COMETIC

    $9.40
    Made in the U.S.A.
    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:
  • COMETIC Top End Gasket - XL 1200 C9177

    COMETIC Top End Gasket - XL 1200 C9177

    COMETIC

    $142.75
    EST (Extreme Sealing Technology) gasket kits include embossed stainless steel head, base, and rocker gaskets covered with a proprietary rubber material, Head gasket material allows heat to be drawn away from the combustion ring and dissipated evenly...
    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
    $142.75
    Qty in Cart: 0
    Quantity:
    Price:
    $142.75
    Subtotal:
  • COMETIC Primary Gasket C9179F1

    COMETIC Primary Gasket C9179F1

    COMETIC

    $46.15
    Cometic's proprietary AFM (Aluminum Foamette Material) gaskets feature an aluminum core with a chemically blown, compounded nitrile synthetic rubber bonded to the outside, Gaskets have resistance to temperatures of more than 2500°F, Have an 85%...
    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')
    $46.15
    Qty in Cart: 0
    Quantity:
    Price:
    $46.15
    Subtotal:
  • COMETIC Complete Gasket Kit - FL 103 C9185

    COMETIC Complete Gasket Kit - FL 103 C9185

    COMETIC

    $287.65
    Every gasket in these kits uses the best materials possible for its intended application, Multi-Layer Steel (MLS) head gaskets, Steel Viton®-coated base gaskets, Blue Viton valve stem seals, Aluminum Foam Material (AFM) race-style exhaust gaskets,...
    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
    $287.65
    Qty in Cart: 0
    Quantity:
    Price:
    $287.65
    Subtotal:
  • COMETIC Complete Gasket Kit - Dyna C9186

    COMETIC Complete Gasket Kit - Dyna C9186

    COMETIC

    $287.65
    Every gasket in these kits uses the best materials possible for its intended application, Multi-Layer Steel (MLS) head gaskets, Steel Viton®-coated base gaskets, Blue Viton valve stem seals, Aluminum Foam Material (AFM) race-style exhaust gaskets,...
    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
    $287.65
    Qty in Cart: 0
    Quantity:
    Price:
    $287.65
    Subtotal:
  • COMETIC Trans End Cover Gasket - Twin Cam C9188

    COMETIC Trans End Cover Gasket - Twin Cam C9188

    COMETIC

    $19.90
    Aluminum Foamette Material gaskets feature an aluminum core and a chemically blown, compounded nitrile synthetic rubber coating that is bonded to the outside layer; do not require gasket sealer., Made in the U.S.A.
    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
    $19.90
    Qty in Cart: 0
    Quantity:
    Price:
    $19.90
    Subtotal:
  • COMETIC Transmission Top Cover Gasket Cover - Twin Cam C9189

    COMETIC Transmission Top Cover Gasket Cover - Twin Cam C9189

    COMETIC

    $18.50
    Aluminum Foamette Material gaskets feature an aluminum core and a chemically blown, compounded nitrile synthetic rubber coating that is bonded to the outside layer; do not require gasket sealer., Made in the U.S.A.
    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')
    $18.50
    Qty in Cart: 0
    Quantity:
    Price:
    $18.50
    Subtotal:
  • COMETIC Rocker Box Kit - XL C9195

    COMETIC Rocker Box Kit - XL C9195

    COMETIC

    $65.05
    Premium materials used for specific applications to provide a long, service free life, Kits include all gaskets, seals, O-rings and quality bolt seals needed when servicing both rocker boxes, Made in the U.S.A.
    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
    $65.05
    Qty in Cart: 0
    Quantity:
    Price:
    $65.05
    Subtotal:
  • COMETIC Exhaust Gasket - EVO/Twin Cam C9540

    COMETIC Exhaust Gasket - EVO/Twin Cam C9540

    COMETIC

    $59.20
    Gasket material and construction will vary by application to ensure longevity with leak free performance under all conditions, 4-stroke applications utilize a double-sided Viton® rubber-coated stainless steel gasket providing precise, high-temperature...
    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
    $59.20
    Qty in Cart: 0
    Quantity:
    Price:
    $59.20
    Subtotal:
  • COMETIC Exhaust Gasket - VROD C9928

    COMETIC Exhaust Gasket - VROD C9928

    COMETIC

    $15.95
    Gasket material and construction will vary by application to ensure longevity with leak free performance under all conditions, 4-stroke applications utilize a double-sided Viton® rubber-coated stainless steel gasket providing precise, high-temperature...
    09341239
    SKU:
    09341239
    Availability:
    Ships Same Business Day
    Weight:
    0.06 LBS
    UNITS:
    PAIR
    PRODUCT NAME:
    GASKET
    MATERIAL:
    GRAPHITE
    RIDING STYLE:
    STREET
    TYPE:
    EXHAUST
    $15.95
    Qty in Cart: 0
    Quantity:
    Price:
    $15.95
    Subtotal:
  • COMETIC Complete Gasket Kit - FLT C9778F

    COMETIC Complete Gasket Kit - FLT C9778F

    COMETIC

    $282.40
    Every gasket in these kits uses the best materials possible for its intended application, Multi-Layer Steel (MLS) head gaskets, Steel Viton®-coated base gaskets, Blue Viton valve stem seals, Aluminum Foam Material (AFM) race-style exhaust gaskets,...
    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
    $282.40
    Qty in Cart: 0
    Quantity:
    Price:
    $282.40
    Subtotal:
  • COMETIC Complete Gasket - Softail/FXD C9751F

    COMETIC Complete Gasket - Softail/FXD C9751F

    COMETIC

    $356.95
    Every gasket in these kits uses the best materials possible for its intended application, Multi-Layer Steel (MLS) head gaskets, Steel Viton®-coated base gaskets, Blue Viton valve stem seals, Aluminum Foam Material (AFM) race-style exhaust gaskets,...
    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
    $356.95
    Qty in Cart: 0
    Quantity:
    Price:
    $356.95
    Subtotal:
  • COMETIC Motor Gasket Kit - Standard - EVO C9891

    COMETIC Motor Gasket Kit - Standard - EVO C9891

    COMETIC

    $183.70
    Every gasket in these kits uses the best materials possible for its intended application, Multi-Layer Steel (MLS) head gaskets, Steel Viton®-coated base gaskets, Blue Viton valve stem seals, Aluminum Foam Material (AFM) race-style exhaust gaskets, Made...
    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
    $183.70
    Qty in Cart: 0
    Quantity:
    Price:
    $183.70
    Subtotal:
  • COMETIC Motor Gasket Kit - Standard - EVO C9890

    COMETIC Motor Gasket Kit - Standard - EVO C9890

    COMETIC

    $159.55
    Every gasket in these kits uses the best materials possible for its intended application, Multi-Layer Steel (MLS) head gaskets, Steel Viton®-coated base gaskets, Blue Viton valve stem seals, Aluminum Foam Material (AFM) race-style exhaust gaskets, Made...
    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
    $159.55
    Qty in Cart: 0
    Quantity:
    Price:
    $159.55
    Subtotal:
  • COMETIC Complete Gasket Kit - Standard - XB9 C9857

    COMETIC Complete Gasket Kit - Standard - XB9 C9857

    COMETIC

    $202.60
    Every gasket in these kits uses the best materials possible for its intended application, Multi-Layer Steel (MLS) head gaskets, Steel Viton®-coated base gaskets, Blue Viton valve stem seals, Aluminum Foam Material (AFM) race-style exhaust gaskets,...
    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
    Qty in Cart: 0
    Quantity:
    Price:
    $202.60
    Subtotal:
  • COMETIC Motor Gasket Kit - XL - .030" C9953

    COMETIC Motor Gasket Kit - XL - .030" C9953

    COMETIC

    $202.60
    Every gasket in these kits uses the best materials possible for its intended application, Multi-Layer Steel (MLS) head gaskets, Steel Viton®-coated base gaskets, Blue Viton valve stem seals, Aluminum Foam Material (AFM) race-style exhaust gaskets,...
    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
    Qty in Cart: 0
    Quantity:
    Price:
    $202.60
    Subtotal:
  • COMETIC Oil Jet Gasket - XL C9962

    COMETIC Oil Jet Gasket - XL C9962

    COMETIC

    $8.50
    Made in the U.S.A.
    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:
    $8.50
    Subtotal:
  • COMETIC Top End Gasket -.045" C9951

    COMETIC Top End Gasket -.045" C9951

    COMETIC

    $150.10
    EST (Extreme Sealing Technology) gasket kits include embossed stainless steel head, base, and rocker gaskets covered with a proprietary rubber material, Head gasket material allows heat to be drawn away from the combustion ring and dissipated evenly...
    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
    $150.10
    Qty in Cart: 0
    Quantity:
    Price:
    $150.10
    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