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ATV/UTV Engine

ATV/UTV Engine

ATV/UTV Engine

ATV/UTV Engine Parts at JJ Motorsports

Maximize your ATV or UTV's engine life with top-quality components from JJ Motorsports. Our selection includes gasket kits, connecting rods, water pump rebuild kits, and timing plugs designed for reliable sealing, strength, and easy installation in demanding off-road conditions. Compatible with Polaris, Can-Am, Honda, and more, these parts ensure peak power, reduced wear, and efficient operation for trail riding or utility work.

Shop trusted brands like Moose Racing for rebuild kits and Winderosa for gaskets. Explore related categories such as ATV/UTV air and fuel for intake upgrades or ATV/UTV drivetrain for transmission enhancements.

Top ATV/UTV 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
  • PROX Piston Kit 01.5805.B

    PROX Piston Kit 01.5805.B

    PROX

    $134.95
    Your engine's pistons are the hardworking center of combustion—and worn or damaged pistons mean loss of compression, power, and reliability. The PROX Piston Kit 01.5805.B delivers OEM-spec...
    09105952
    SKU:
    09105952
    Availability:
    Ships Same Business Day
    Weight:
    0.80 LBS
    RIDING STYLE:
    UTV
    PISTON MATERIAL:
    ALUMINUM ALLOY
    PRODUCT NAME:
    PISTON KIT
    RIDING STYLE:
    ATV
    BORE SIZE METRIC:
    79.96 MM
    UNITS:
    KIT
    $134.95
    Qty in Cart: 0
    Quantity:
    Price:
    $134.95
    Subtotal:
  • PROX Crank Bearing and Seal Kit 23.CBS22088

    PROX Crank Bearing and Seal Kit 23.CBS22088

    PROX

    $115.95
    A compromised crankshaft bearing or seal will rob horsepower, create catastrophic engine damage, and leave you stranded. The PROX Crank Bearing and Seal Kit 23.CBS22088 delivers exact...
    09240317
    SKU:
    09240317
    Availability:
    Ships Same Business Day
    Weight:
    1.00 LBS
    UNITS:
    KIT
    APPLICATION:
    CRANKSHAFT
    RIDING STYLE:
    ATV
    STYLE:
    2-STROKE
    PRODUCT NAME:
    BEARING AND SEAL KIT
    TYPE:
    BALL
    Qty in Cart: 0
    Quantity:
    Price:
    $115.95
    Subtotal:
  • PROX Crank Bearing and Seal Kit 23.CBS23098

    PROX Crank Bearing and Seal Kit 23.CBS23098

    PROX

    $65.95
    A complete crank bearing and seal kit is essential for any bottom-end rebuild—it ensures proper clearances, oil distribution, and crankshaft stability under load. Using OEM-spec components eliminates...
    09240325
    SKU:
    09240325
    Availability:
    Ships Same Business Day
    Weight:
    1.55 LBS
    PRODUCT NAME:
    BEARING AND SEAL KIT
    TYPE:
    BALL
    RIDING STYLE:
    OFF-ROAD
    UNITS:
    KIT
    STYLE:
    2-STROKE
    APPLICATION:
    CRANKSHAFT
    Qty in Cart: 0
    Quantity:
    Price:
    $65.95
    Subtotal:
  • PROX Crank Bearing and Seal Kit 23.CBS33088

    PROX Crank Bearing and Seal Kit 23.CBS33088

    PROX

    $70.95
    A compromised crankshaft bearing or seal can introduce catastrophic wear into your engine's most critical rotating assembly. This PROX kit delivers OEM-specification replacements, ensuring your crank...
    09240340
    SKU:
    09240340
    Availability:
    Ships Same Business Day
    Weight:
    1.10 LBS
    UNITS:
    KIT
    RIDING STYLE:
    ATV
    STYLE:
    2-STROKE
    APPLICATION:
    CRANKSHAFT
    TYPE:
    BALL
    PRODUCT NAME:
    BEARING AND SEAL KIT
    $70.95
    Qty in Cart: 0
    Quantity:
    Price:
    $70.95
    Subtotal:
  • PROX Crank Bearing and Seal Kit 23.CBS34000

    PROX Crank Bearing and Seal Kit 23.CBS34000

    PROX

    $127.95
    A crank bearing and seal kit is essential maintenance for any high-performance engine—worn bearings increase friction, reduce efficiency, and accelerate wear on your crankshaft. This PROX kit...
    09240345
    SKU:
    09240345
    Availability:
    Ships Same Business Day
    Weight:
    1.52 LBS
    APPLICATION:
    CRANKSHAFT
    PRODUCT NAME:
    BEARING SET
    UNITS:
    KIT
    TYPE:
    BALL
    RIDING STYLE:
    ATV
    STYLE:
    4-STROKE
    $127.95
    Qty in Cart: 0
    Quantity:
    Price:
    $127.95
    Subtotal:
  • PROX Crank Bearing and Seal Kit 23.CBS64003

    PROX Crank Bearing and Seal Kit 23.CBS64003

    PROX

    $156.95
    A crankshaft bearing and seal kit is essential maintenance for any high-performance engine—neglecting worn bearings leads to catastrophic failure and costly downtime. This PROX kit delivers...
    09240367
    SKU:
    09240367
    Availability:
    Ships Same Business Day
    Weight:
    1.04 LBS
    UNITS:
    KIT
    APPLICATION:
    CRANKSHAFT
    TYPE:
    BALL
    RIDING STYLE:
    ATV
    STYLE:
    4-STROKE
    PRODUCT NAME:
    BEARING AND SEAL KIT
    $156.95
    Qty in Cart: 0
    Quantity:
    Price:
    $156.95
    Subtotal:
  • PROX Connecting Rod Kit - Yamaha YFM700R 03.2706

    PROX Connecting Rod Kit - Yamaha YFM700R 03.2706

    PROX

    $188.95
    A connecting rod failure mid-race or trail can leave you stranded—and potentially damage your entire bottom end. The PROX Connecting Rod Kit for the Yamaha YFM700R delivers the precision engineering...
    09230631
    SKU:
    09230631
    Availability:
    Ships Same Business Day
    Weight:
    2.35 LBS
    RIDING STYLE:
    ATV
    PRODUCT NAME:
    CONNECTING ROD KIT
    UNITS:
    KIT
    RIDING STYLE:
    UTV
    $188.95
    Qty in Cart: 0
    Quantity:
    Price:
    $188.95
    Subtotal:
  • PROX Connecting Rod Kit - Yamaha YFZ450R 03.2444

    PROX Connecting Rod Kit - Yamaha YFZ450R 03.2444

    PROX

    $183.95
    A connecting rod failure mid-race means a blown engine and a day off the track—or worse. The PROX Connecting Rod Kit for Yamaha YFZ450R delivers the durability and precision tolerances you need to...
    09230632
    SKU:
    09230632
    Availability:
    Ships Same Business Day
    Weight:
    1.90 LBS
    PRODUCT NAME:
    CONNECTING ROD KIT
    RIDING STYLE:
    ATV
    UNITS:
    KIT
    $183.95
    Qty in Cart: 0
    Quantity:
    Price:
    $183.95
    Subtotal:
  • PROX Connecting Rod Kit 03.1300

    PROX Connecting Rod Kit 03.1300

    PROX

    $132.95
    A connecting rod failure can end your race day—or worse, your engine. The PROX Connecting Rod Kit 03.1300 gives you the reliability and precision clearances needed to handle sustained high RPM...
    09230278
    SKU:
    09230278
    Availability:
    Ships Same Business Day
    Weight:
    0.95 LBS
    UNITS:
    EACH
    RIDING STYLE:
    ATV
    PRODUCT NAME:
    CONNECTING ROD KIT
    ENGINE TYPE:
    2-STROKE
    MATERIAL:
    FORGED STEEL
    $132.95
    Qty in Cart: 0
    Quantity:
    Price:
    $132.95
    Subtotal:
  • PROX Connecting Rod Kit - Yamaha YFZ450 03.2436

    PROX Connecting Rod Kit - Yamaha YFZ450 03.2436

    PROX

    $183.95
    The PROX Connecting Rod Kit restores critical engine integrity on your Yamaha YFZ450, ensuring reliable power transfer from combustion to crankshaft. Whether you're rebuilding after high-RPM racing...
    09230231
    SKU:
    09230231
    Availability:
    Ships Same Business Day
    Weight:
    1.56 LBS
    ENGINE TYPE:
    4-STROKE
    PRODUCT NAME:
    CONNECTING ROD KIT
    RIDING STYLE:
    ATV
    MATERIAL:
    FORGED
    MATERIAL:
    STEEL
    UNITS:
    KIT
    $183.95
    Qty in Cart: 0
    Quantity:
    Price:
    $183.95
    Subtotal:
  • PROX Connecting Rod Kit - Honda XL125S 03.1253

    PROX Connecting Rod Kit - Honda XL125S 03.1253

    PROX

    $98.95
    A worn or damaged connecting rod compromises your engine's reliability and performance, risking catastrophic failure under load. The PROX Connecting Rod Kit for Honda XL125S delivers OEM-quality...
    09230234
    SKU:
    09230234
    Availability:
    Ships Same Business Day
    Weight:
    1.20 LBS
    MATERIAL:
    STEEL
    PRODUCT NAME:
    CONNECTING ROD KIT
    ENGINE TYPE:
    4-STROKE
    MATERIAL:
    FORGED
    RIDING STYLE:
    OFF-ROAD
    UNITS:
    KIT
    $98.95
    Qty in Cart: 0
    Quantity:
    Price:
    $98.95
    Subtotal:
  • PROX Connecting Rod Kit 03.6427

    PROX Connecting Rod Kit 03.6427

    PROX

    $179.95
    A connecting rod is the critical link between your crankshaft and piston, and PROX engineered this kit to handle sustained high-RPM loads without compromise. The 03.6427 arrives as a complete...
    09230235
    SKU:
    09230235
    Availability:
    Ships Same Business Day
    Weight:
    1.71 LBS
    UNITS:
    EACH
    ENGINE TYPE:
    4-STROKE
    RIDING STYLE:
    ATV
    PRODUCT NAME:
    CONNECTING ROD KIT
    MATERIAL:
    FORGED STEEL
    RIDING STYLE:
    OFF-ROAD
    $179.95
    Qty in Cart: 0
    Quantity:
    Price:
    $179.95
    Subtotal:
  • PROX Connecting Rod 03.2310F

    PROX Connecting Rod 03.2310F

    PROX

    $132.95
    A connecting rod is the critical link between your piston and crankshaft—its strength and precision directly impact engine reliability and power delivery. The PROX Connecting Rod 03.2310F is...
    09230146
    SKU:
    09230146
    Availability:
    Ships Same Business Day
    Weight:
    0.78 LBS
    ENGINE TYPE:
    2-STROKE
    MATERIAL:
    FORGED STEEL
    PRODUCT NAME:
    CONNECTING ROD KIT
    RIDING STYLE:
    ATV
    UNITS:
    EACH
    $132.95
    Qty in Cart: 0
    Quantity:
    Price:
    $132.95
    Subtotal:
  • PROX Connecting Rod 03.2434

    PROX Connecting Rod 03.2434

    PROX

    $175.95
    A connecting rod is the critical link between your crankshaft and piston, transmitting combustion forces while managing rotational stress at extreme RPMs. The PROX 03.2434 delivers reliable...
    09230177
    SKU:
    09230177
    Availability:
    Ships Same Business Day
    Weight:
    1.51 LBS
    MATERIAL:
    FORGED STEEL
    PRODUCT NAME:
    CONNECTING ROD KIT
    RIDING STYLE:
    ATV
    ENGINE TYPE:
    4-STROKE
    UNITS:
    EACH
    Qty in Cart: 0
    Quantity:
    Price:
    $175.95
    Subtotal:
  • PROX Ring Set 02.1495.000

    PROX Ring Set 02.1495.000

    PROX

    $49.95
    Piston ring failure compromises compression, oil control, and engine efficiency—leading to power loss, increased blowby, and accelerated wear. The PROX Ring Set 02.1495.000 delivers OEM-specification...
    PX2500R
    SKU:
    PX2500R
    Availability:
    Ships Same Business Day
    Weight:
    0.06 LBS
    PRODUCT NAME:
    PISTON RING
    RIDING STYLE:
    OFF-ROAD
    PISTON MATERIAL:
    ALUMINUM ALLOY
    RIDING STYLE:
    ATV
    UNITS:
    SET
    Qty in Cart: 0
    Quantity:
    Price:
    $49.95
    Subtotal:
  • PROX Ring Set 02.1495.025

    PROX Ring Set 02.1495.025

    PROX

    $47.34
    Piston ring sets are critical to engine performance—they seal combustion pressure, regulate oil consumption, and directly impact compression, power delivery, and engine longevity. The PROX Ring Set...
    PX2501R
    SKU:
    PX2501R
    Availability:
    Ships Same Business Day
    Weight:
    0.06 LBS
    UNITS:
    SET
    PRODUCT NAME:
    PISTON RING
    PISTON MATERIAL:
    ALUMINUM ALLOY
    RIDING STYLE:
    ATV
    RIDING STYLE:
    OFF-ROAD
    Qty in Cart: 0
    Quantity:
    Price:
    $47.34
    Subtotal:
  • PROX Piston Kit 01.1495.050

    PROX Piston Kit 01.1495.050

    PROX

    $155.95
    When your engine demands reliability at high RPM, OEM-quality pistons are non-negotiable. The PROX Piston Kit 01.1495.050 delivers factory-spec performance without compromise, engineered to handle...
    PX2502
    SKU:
    PX2502
    Availability:
    Ships Same Business Day
    Weight:
    0.98 LBS
    PISTON DIAMETER METRIC:
    85.50 MM
    RIDING STYLE:
    OFF-ROAD
    ENGINE TYPE:
    4-STROKE
    PRODUCT NAME:
    PISTON KIT
    RIDING STYLE:
    ATV
    BORE SIZE METRIC:
    85.50 MM
    PISTON MATERIAL:
    ALUMINUM ALLOY
    PISTON SIZE IMPERIAL:
    +0.020'
    UNITS:
    EACH
    $155.95
    Qty in Cart: 0
    Quantity:
    Price:
    $155.95
    Subtotal:
  • PROX Piston Kit 01.1495.100

    PROX Piston Kit 01.1495.100

    PROX

    $139.95
    Worn or damaged pistons compromise combustion efficiency, reduce power output, and risk catastrophic engine failure. The PROX Piston Kit 01.1495.100 restores your engine to OEM performance...
    PX2504
    SKU:
    PX2504
    Availability:
    Ships Same Business Day
    Weight:
    0.98 LBS
    PISTON DIAMETER METRIC:
    86.00 MM
    RIDING STYLE:
    OFF-ROAD
    ENGINE TYPE:
    4-STROKE
    PISTON MATERIAL:
    ALUMINUM ALLOY
    PISTON SIZE IMPERIAL:
    +0.040'
    PRODUCT NAME:
    PISTON KIT
    RIDING STYLE:
    ATV
    UNITS:
    EACH
    BORE SIZE METRIC:
    86.00 MM
    Qty in Cart: 0
    Quantity:
    Price:
    $139.95
    Subtotal:
  • PROX Piston Kit 01.2281.000

    PROX Piston Kit 01.2281.000

    PROX

    $121.95
    When your engine's pistons wear beyond serviceable limits, you need a replacement that matches OEM performance without compromise. The PROX Piston Kit 01.2281.000 delivers precision-engineered...
    PX4170
    SKU:
    PX4170
    Availability:
    Ships Same Business Day
    Weight:
    0.63 LBS
    BORE SIZE METRIC:
    66.00 MM
    ENGINE TYPE:
    2-STROKE
    PISTON SIZE METRIC:
    STANDARD
    PRODUCT NAME:
    PISTON KIT
    RIDING STYLE:
    ATV
    UNITS:
    EACH
    PISTON DIAMETER METRIC:
    66.35 MM
    PISTON MATERIAL:
    ALUMINUM ALLOY
    $121.95
    Qty in Cart: 0
    Quantity:
    Price:
    $121.95
    Subtotal:
  • PROX Piston Kit 01.2281.150

    PROX Piston Kit 01.2281.150

    PROX

    $105.95
    A piston kit is the heart of engine reliability and performance—worn or damaged pistons compromise combustion efficiency, increase blowby, and accelerate wear throughout your engine. The PROX Piston...
    PX4176
    SKU:
    PX4176
    Availability:
    Ships Same Business Day
    Weight:
    0.69 LBS
    PISTON MATERIAL:
    ALUMINUM ALLOY
    RIDING STYLE:
    ATV
    UNITS:
    EACH
    PRODUCT NAME:
    PISTON KIT
    BORE SIZE METRIC:
    67.50 MM
    ENGINE TYPE:
    2-STROKE
    PISTON DIAMETER METRIC:
    67.50 MM
    PISTON SIZE METRIC:
    +1.50 MM
    Qty in Cart: 0
    Quantity:
    Price:
    $105.95
    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

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