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
- MOOSE UTILITY Clutch Cover Gasket Seal 500-1265-PU – Durable seal for clutch cover protection.
- WINDEROSA Standard Bore Gasket Kit 810585 – Complete kit for engine sealing and rebuilds.
- WORKS CONNECTION Engine Timing Plug 24-590 – Precision plug for accurate timing adjustments.
- MOOSE RACING Connecting Rod MR5026 – High-strength rod for engine durability.
- MOOSE RACING Water Pump Rebuild Kit 821865 – Comprehensive kit for water pump maintenance.
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
-
WSM Top End Kit - .25mm - Kawasaki 54-257-11
WSM
$146.14A top-end rebuild is essential maintenance for any 4-stroke engine pushing hard on the track or trail. This WSM Top End Kit delivers OEM-quality components in one complete package, eliminating the...09031392- SKU:
- 09031392
- Availability:
- Ships Same Business Day
- Weight:
- 1.75 LBS
- OVERBORE METRIC:
- +0.25 MM
- RIDING STYLE:
- ATV
- UNITS:
- KIT
- PRODUCT NAME:
- PISTON KIT
$146.14Qty in Cart: 0Quantity:Price:$146.14Subtotal: -
WSM Top End Kit - 1mm - Kawasaki 54-257-14
WSM
$136.45A worn top end compromises combustion efficiency, power delivery, and engine longevity. This WSM Top End Kit delivers OEM-quality components engineered to restore your 4-stroke's performance and...09031395- SKU:
- 09031395
- Availability:
- Ships Same Business Day
- Weight:
- 1.75 LBS
- OVERBORE METRIC:
- +1.00 MM
- RIDING STYLE:
- ATV
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- KIT
$136.45Qty in Cart: 0Quantity:Price:$136.45Subtotal: -
WSM Top End Kit - Standard - Kawasaki 54-258-10
WSM
$289.93A top-end rebuild demands precision components that restore your engine to factory specifications—or exceed them. The WSM Top End Kit eliminates the guesswork by bundling all critical components you...09031396- SKU:
- 09031396
- Availability:
- Ships Same Business Day
- Weight:
- 3.15 LBS
- UNITS:
- KIT
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- ATV
- OVERBORE METRIC:
- STANDARD
$289.93 -
WSM Top End Kit - .25mm - Kawasaki 54-258-11
WSM
$276.12A worn or damaged top end can tank your engine's compression, power delivery, and reliability—especially on a high-revving 4-stroke where every seal matters. The WSM Top End Kit gives you...09031397- SKU:
- 09031397
- Availability:
- Ships Same Business Day
- Weight:
- 3.20 LBS
- OVERBORE METRIC:
- +0.25 MM
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- ATV
- UNITS:
- KIT
$276.12Qty in Cart: 0Quantity:Price:$276.12Subtotal: -
WSM Top End Kit - .5mm - Kawasaki 54-258-12
WSM
$276.12A worn or damaged top end compromises compression, efficiency, and throttle response—costing you performance when it matters most. The WSM Top End Kit delivers OEM-equivalent quality components in a...09031398- SKU:
- 09031398
- Availability:
- Ships Same Business Day
- Weight:
- 2.25 LBS
- OVERBORE METRIC:
- +0.50 MM
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- ATV
- UNITS:
- KIT
$276.12Qty in Cart: 0Quantity:Price:$276.12Subtotal: -
WSM Top End Kit - 1mm - Kawasaki 54-258-14
WSM
$289.93A top-end rebuild is essential when your 4-stroke engine shows signs of wear—loss of compression, increased blow-by, or declining power output. The WSM Top End Kit delivers everything you need for a...09031400- SKU:
- 09031400
- Availability:
- Ships Same Business Day
- Weight:
- 3.30 LBS
- UNITS:
- KIT
- OVERBORE METRIC:
- +1.00 MM
- RIDING STYLE:
- ATV
- PRODUCT NAME:
- PISTON KIT
$289.93 -
WSM Top End Kit - Standard - Kawasaki 54-256-10
WSM
$289.93A worn or damaged top end compromises compression, power delivery, and engine reliability—especially critical if you're pushing your Kawasaki 4-stroke to its limits. The WSM Top End Kit delivers...09031401- SKU:
- 09031401
- Availability:
- Ships Same Business Day
- Weight:
- 3.05 LBS
- OVERBORE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- KIT
- RIDING STYLE:
- ATV
$289.93Qty in Cart: 0Quantity:Price:$289.93Subtotal: -
WSM Top End Kit - .25mm - Kawasaki 54-256-11
WSM
$289.93A worn or damaged top end compromises your engine's compression, efficiency, and reliability—whether you're racing or putting miles on your machine. The WSM Top End Kit delivers OEM-quality...09031402- SKU:
- 09031402
- Availability:
- Ships Same Business Day
- Weight:
- 3.05 LBS
- UNITS:
- KIT
- OVERBORE METRIC:
- +0.25 MM
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- ATV
$289.93Qty in Cart: 0Quantity:Price:$289.93Subtotal: -
WSM Top End Kit - Standard - Polaris 54-311-10
WSM
$197.10A worn or damaged top end severely compromises engine efficiency, throttle response, and overall reliability. The WSM Top End Kit delivers OEM-quality components engineered to restore your Polaris...09031406- SKU:
- 09031406
- Availability:
- Ships Same Business Day
- Weight:
- 2.75 LBS
- PRODUCT NAME:
- PISTON KIT
- OVERBORE METRIC:
- STANDARD
- RIDING STYLE:
- ATV
- UNITS:
- KIT
$197.10 -
WSM Top End Kit - .25mm - Polaris 54-311-11
WSM
$197.10Engine wear happens. When your Polaris 4-stroke top end starts losing compression and power, a complete piston kit rebuild restores factory performance without the downtime of a full engine overhaul...09031407- SKU:
- 09031407
- Availability:
- Ships Same Business Day
- Weight:
- 2.75 LBS
- OVERBORE METRIC:
- +0.25 MM
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- ATV
- UNITS:
- KIT
$197.10Qty in Cart: 0Quantity:Price:$197.10Subtotal: -
WSM Top End Kit - .5mm - Polaris 54-311-12
WSM
$197.10A worn or damaged top end compromises ring seal, reduces compression, and kills power output. The WSM Top End Kit gives you factory-fresh performance with precision-manufactured components engineered...09031408- SKU:
- 09031408
- Availability:
- Ships Same Business Day
- Weight:
- 2.65 LBS
- OVERBORE METRIC:
- +0.50 MM
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- ATV
- UNITS:
- KIT
$197.10 -
WSM Top End Kit - .75mm - Polaris 54-311-13
WSM
$197.10A worn or damaged top end doesn't just cost you power—it compromises reliability when you need it most. The WSM Top End Kit delivers OEM-quality components engineered to restore your 4-stroke engine...09031409- SKU:
- 09031409
- Availability:
- Ships Same Business Day
- Weight:
- 2.75 LBS
- UNITS:
- KIT
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- ATV
- OVERBORE METRIC:
- +0.75 MM
$197.10 -
WSM Top End Kit - Standard - Yamaha 54-536-10
WSM
$105.15A worn or damaged top end compromises engine efficiency, power output, and reliability. This WSM Top End Kit delivers OEM-quality components engineered to restore your engine to factory...09031411- SKU:
- 09031411
- Availability:
- Ships Same Business Day
- Weight:
- 0.75 LBS
- UNITS:
- KIT
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- ATV
- OVERBORE METRIC:
- STANDARD
$105.15 -
WSM Top End Kit - .25mm - Yamaha 54-536-11
WSM
$105.15A top-end rebuild is essential to restoring cylinder head performance and maintaining compression integrity in your 4-stroke engine. This complete WSM piston kit eliminates the guesswork of sourcing...09031412- SKU:
- 09031412
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
- PRODUCT NAME:
- PISTON KIT
- OVERBORE METRIC:
- +0.25 MM
- RIDING STYLE:
- ATV
- UNITS:
- KIT
$105.15Qty in Cart: 0Quantity:Price:$105.15Subtotal: -
WSM Top End Kit - .5mm - Yamaha 54-536-12
WSM
$105.15A top-end rebuild is critical to maintaining peak compression, ring seal, and combustion efficiency—especially in high-RPM applications where factory tolerances have worn beyond spec. The WSM Top End...09031413- SKU:
- 09031413
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
- OVERBORE METRIC:
- +0.50 MM
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- ATV
- UNITS:
- KIT
$105.15Qty in Cart: 0Quantity:Price:$105.15Subtotal: -
WSM Top End Kit - 1mm - Yamaha 54-536-14
WSM
$100.14A complete top-end rebuild requires precision components that work in harmony—and this WSM kit delivers exactly that. Whether you're recovering from bearing wear, restoring compression, or upgrading...09031415- SKU:
- 09031415
- Availability:
- Ships Same Business Day
- Weight:
- 0.95 LBS
- PRODUCT NAME:
- PISTON KIT
- OVERBORE METRIC:
- +1.00 MM
- RIDING STYLE:
- ATV
- UNITS:
- KIT
$100.14Qty in Cart: 0Quantity:Price:$100.14Subtotal: -
WSM Top End Kit - Standard - Yamaha 54-540-10
WSM
$150.15A complete top-end rebuild requires precision components engineered to exact tolerances, and the WSM Top End Kit delivers everything you need in one package. Whether you're restoring a worn engine or...09031416- SKU:
- 09031416
- Availability:
- Ships Same Business Day
- Weight:
- 2.00 LBS
- OVERBORE METRIC:
- STANDARD
- UNITS:
- KIT
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- ATV
$150.15 -
WSM Top End Kit - .5mm - Yamaha 54-540-12
WSM
$150.15A properly sized top end directly impacts ring seal, compression ratio, and combustion efficiency—all critical factors in extracting reliable power from your 4-stroke engine. WSM's .5mm oversized...09031418- SKU:
- 09031418
- Availability:
- Ships Same Business Day
- Weight:
- 1.80 LBS
- UNITS:
- KIT
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- ATV
- OVERBORE METRIC:
- +0.50 MM
$150.15 -
WSM Top End Kit - .75mm - Yamaha 54-540-13
WSM
$150.15A complete top-end rebuild requires precision components that work in concert—and compromising on any single element undermines the entire assembly. The WSM Top End Kit delivers OEM-quality pistons,...09031419- SKU:
- 09031419
- Availability:
- Ships Same Business Day
- Weight:
- 1.95 LBS
- OVERBORE METRIC:
- +0.75 MM
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- ATV
- UNITS:
- KIT
$150.15 -
WSM Top End Kit - 1mm - Yamaha 54-540-14
WSM
$143.00A top-end rebuild demands precision components that restore your engine to factory specifications—or better. The WSM Top End Kit delivers OEM-quality pistons and supporting hardware in a single...09031420- SKU:
- 09031420
- Availability:
- Ships Same Business Day
- Weight:
- 1.90 LBS
- PRODUCT NAME:
- PISTON KIT
- OVERBORE METRIC:
- +1.00 MM
- RIDING STYLE:
- ATV
- UNITS:
- KIT
$143.00Qty in Cart: 0Quantity:Price:$143.00Subtotal:
