Dirt Bike Engine
Dirt Bike Engine Parts at JJ Motorsports
Discover a full range of dirt bike engine components for rebuilding or upgrading your performance from JJ Motorsports. From crankshafts to cylinder heads and piston kits, these precision-engineered components ensure reliable performance. For additional upgrades, check out our full selection of off-road dirt bike parts to keep your engine running at peak efficiency on the track or trails.
Shop trusted brands like Wiseco for forged piston kits and K&N for high-flow oil filters. Explore related categories such as Dirt Bike Air and Fuel for intake upgrades or Dirt Bike Exhaust for complete systems.
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
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BOYESEN Clutch Cover - Gold - WR/YZ450 CC-38M
BOYESEN
$95.95If you're running a WR/YZ450, factory clutch covers are a weak point—heavy, prone to leaks, and a visual liability. The BOYESEN Lightweight Clutch Cover cuts unnecessary weight while delivering the precision engineering and durability that separates...09400239- SKU:
- 09400239
- Availability:
- Ships Same Business Day
- Weight:
- 0.84 LBS
- RIDING STYLE:
- OFF-ROAD
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- TYPE:
- CLUTCH
- UNITS:
- EACH
- PRODUCT NAME:
- COVER
$95.95 -
BOYESEN Clutch Cover - Black - WR450 CC-38B
BOYESEN
$95.95A factory clutch cover protects one of the most critical components on your WR450, and the BOYESEN CC-38B delivers that protection without sacrificing weight or aesthetics. Individually surfaced for a precise fit, this cover eliminates the leak points...09400238- SKU:
- 09400238
- Availability:
- Ships Same Business Day
- Weight:
- 0.87 LBS
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
- COLOR/FINISH:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
$95.95 -
BOYESEN Clutch Cover - Gold - YZ250 CC-32AM
BOYESEN
$95.95A factory clutch cover that doesn't leak or fail mid-race saves you time, money, and frustration on the track. The BOYESEN CC-32AM delivers lightweight construction without compromising durability, so you get the weight savings that matter while...09400236- SKU:
- 09400236
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
- COLOR/FINISH:
- MAGNESIUM
$95.95 -
HOT RODS Top End Bearing WB110
HOT RODS
$21.95The piston end of your connecting rod endures extreme reciprocating forces at high RPM, and bearing failure means catastrophic engine damage. The HOT RODS Top End Bearing WB110 delivers the needle-cage precision and load-carrying capacity your engine...09240570- SKU:
- 09240570
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- TYPE:
- WRIST PIN
- PRODUCT NAME:
- BEARING
- APPLICATION:
- CONNECTING ROD
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$21.95 -
HOT RODS Top End Bearing WB111
HOT RODS
$21.95The HOT RODS Top End Bearing WB111 is engineered to handle extreme pressures at the piston end of your connecting rod, where combustion forces peak thousands of times per minute. A quality needle-cage bearing here directly reduces friction loss, extends...09240571- SKU:
- 09240571
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- APPLICATION:
- CONNECTING ROD
- UNITS:
- EACH
- TYPE:
- WRIST PIN
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- BEARING
$21.95 -
HOT RODS Top End Bearing WB117
HOT RODS
$22.95The HOT RODS Top End Bearing WB117 is engineered to handle the extreme oscillating loads at the piston pin junction, where metal-to-metal contact and friction can quickly degrade performance and reliability. A precision needle-cage bearing at this...09240572- SKU:
- 09240572
- Availability:
- Ships Same Business Day
- Weight:
- 0.03 LBS
- APPLICATION:
- CONNECTING ROD
- UNITS:
- EACH
- PRODUCT NAME:
- BEARING
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WRIST PIN
$22.95 -
HOT RODS Top End Bearing WB118
HOT RODS
$22.95A quality top-end bearing is critical to extending rod life and maintaining consistent power delivery under sustained high RPM operation. The HOT RODS WB118 needle-cage bearing is engineered for the piston end of the rod, where precision tolerances and...09240573- SKU:
- 09240573
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- TYPE:
- WRIST PIN
- UNITS:
- EACH
- APPLICATION:
- CONNECTING ROD
- PRODUCT NAME:
- BEARING
- RIDING STYLE:
- OFF-ROAD
$22.95Qty in Cart: 0Quantity:Price:$22.95Subtotal: -
HOT RODS Top End Bearing WB128
HOT RODS
$22.95The HOT RODS Top End Bearing WB128 is engineered for the high-stress piston end of your connecting rod, where precision and durability directly impact engine reliability and performance. A quality needle-cage bearing at this critical junction reduces...09240575- SKU:
- 09240575
- Availability:
- Ships Same Business Day
- Weight:
- 0.06 LBS
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- APPLICATION:
- CONNECTING ROD
- PRODUCT NAME:
- BEARING
- TYPE:
- WRIST PIN
$22.95 -
HOT RODS Top End Bearing WB139
HOT RODS
$19.95The piston end of your connecting rod demands precision engineering to handle extreme reciprocating forces and temperature cycling. A worn or substandard needle-cage bearing here directly compromises engine reliability, power delivery, and component...09240576- SKU:
- 09240576
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- PRODUCT NAME:
- BEARING
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- APPLICATION:
- CONNECTING ROD
- TYPE:
- WRIST PIN
$19.95 -
HOT RODS Top End Bearing WB143
HOT RODS
$19.95The connecting rod is one of the most mechanically stressed components in any engine, transmitting enormous forces between the piston and crankshaft thousands of times per minute. A quality top-end bearing like the HOT RODS WB143 is essential for...09240577- SKU:
- 09240577
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- APPLICATION:
- CONNECTING ROD
- UNITS:
- EACH
- TYPE:
- WRIST PIN
- PRODUCT NAME:
- BEARING
- RIDING STYLE:
- OFF-ROAD
$19.95 -
HOT RODS Top End Bearing WB144
HOT RODS
$22.95The piston end of your connecting rod endures extreme cyclic loading with every combustion event—inadequate bearing support here compromises both reliability and peak horsepower delivery. The HOT RODS Top End Bearing WB144 is a precision needle-cage...09240578- SKU:
- 09240578
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- APPLICATION:
- CONNECTING ROD
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- PRODUCT NAME:
- BEARING
- TYPE:
- WRIST PIN
$22.95 -
HOT RODS Crank Bearings K002
HOT RODS
$78.95A quality crankshaft assembly is only as reliable as its bearing system. The HOT RODS Crank Bearings K002 deliver precision-engineered main bearing and seal kits designed to handle the extreme pressures and rotational speeds of high-performance engines...09240021- SKU:
- 09240021
- Availability:
- Ships Same Business Day
- Weight:
- 0.87 LBS
- APPLICATION:
- MAIN CRANKSHAFT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- BEARING
- TYPE:
- BALL
$78.95 -
HOT RODS Crank Bearings K003
HOT RODS
$107.95A crankshaft is only as reliable as its bearings. The HOT RODS K003 crank bearing and seal kit ensures proper load distribution, reduced friction, and maximum longevity in high-RPM applications. Whether you're running a stock rebuild or a heavily...09240022- SKU:
- 09240022
- Availability:
- Ships Same Business Day
- Weight:
- 1.40 LBS
- PRODUCT NAME:
- BEARING
- TYPE:
- BALL
- APPLICATION:
- MAIN CRANKSHAFT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$107.95 -
HOT RODS Crank Bearings K019
HOT RODS
$85.95A quality crankshaft assembly is only as reliable as its bearing package. The HOT RODS K019 Crank Bearings deliver precision-engineered main bearing and seal kits that ensure proper load distribution, minimize friction, and maintain critical clearances...09240023- SKU:
- 09240023
- Availability:
- Ships Same Business Day
- Weight:
- 1.60 LBS
- APPLICATION:
- MAIN CRANKSHAFT
- TYPE:
- BALL
- PRODUCT NAME:
- BEARING
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$85.95Qty in Cart: 0Quantity:Price:$85.95Subtotal: -
HOT RODS Crank Bearings K004
HOT RODS
$78.95A quality crankshaft is only as reliable as the bearings supporting it. HOT RODS K004 crank bearings are precision-engineered main bearing and seal kits designed to work seamlessly with HOT RODS crankshaft assemblies, ensuring proper load distribution,...09240024- SKU:
- 09240024
- Availability:
- Ships Same Business Day
- Weight:
- 0.75 LBS
- APPLICATION:
- MAIN CRANKSHAFT
- UNITS:
- KIT
- PRODUCT NAME:
- BEARING
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- BALL
$78.95 -
HOT RODS Crank Bearings K227
HOT RODS
$129.95A crankshaft assembly is only as reliable as the bearings supporting it. The HOT RODS K227 crank bearing and seal kit ensures proper load distribution, reduces friction, and maintains critical clearances—essential for sustained high-RPM performance and...09240026- SKU:
- 09240026
- Availability:
- Ships Same Business Day
- Weight:
- 1.60 LBS
- APPLICATION:
- MAIN CRANKSHAFT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- BEARING
- TYPE:
- BALL
$129.95Qty in Cart: 0Quantity:Price:$129.95Subtotal: -
HOT RODS Crank Bearings K020
HOT RODS
$70.97A crankshaft is only as reliable as its bearings. The HOT RODS K020 crank bearing and seal kit ensures proper load distribution, reduced friction, and extended engine longevity—critical for both street and track applications where bearing failure means...09240027- SKU:
- 09240027
- Availability:
- Ships Same Business Day
- Weight:
- 0.74 LBS
- APPLICATION:
- MAIN CRANKSHAFT
- PRODUCT NAME:
- BEARING
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- BALL
$70.97Qty in Cart: 0Quantity:Price:$70.97Subtotal: -
HOT RODS Crank Bearings K006
HOT RODS
$117.95A crankshaft is only as reliable as its bearings. The HOT RODS Crank Bearings K006 deliver precision-engineered main bearing and seal kits that eliminate play, reduce friction, and ensure consistent oil delivery under extreme loads. Whether you're...09240028- SKU:
- 09240028
- Availability:
- Ships Same Business Day
- Weight:
- 0.88 LBS
- TYPE:
- BALL
- PRODUCT NAME:
- BEARING
- RIDING STYLE:
- OFF-ROAD
- APPLICATION:
- MAIN CRANKSHAFT
- UNITS:
- KIT
$117.95 -
HOT RODS Crankshaft 4022
HOT RODS
$609.95The HOT RODS Crankshaft 4022 is factory-assembled and trued to OEM specifications, delivering reliable performance whether you're rebuilding a stock engine or pushing it to the limit. This complete crankshaft assembly arrives ready for installation,...09210546- SKU:
- 09210546
- Availability:
- Ships Same Business Day
- Weight:
- 0.01 LBS
- DISPLACEMENT:
- 250 CC
- MATERIAL:
- 4140 STEEL
- STROKE LENGTH METRIC:
- 53.60 MM
- UNITS:
- ASSEMBLY
- COLOR/FINISH:
- STEEL
- FEATURES:
- STANDARD CRANKSHAFT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- OEM STROKE
- MODEL:
- 4-CYCLE
- PRODUCT NAME:
- CRANKSHAFT ASSEMBLY
$609.95 -
HOT RODS Bottom End Kit CBK0207
HOT RODS
$531.95A complete crankshaft installation demands precision and reliability—this kit eliminates guesswork by bundling everything you need in one package. Whether you're building a stroker engine or completing a full rebuild, the HOT RODS Bottom End Kit CBK0207...09210573- SKU:
- 09210573
- Availability:
- Ships Same Business Day
- Weight:
- 6.70 LBS
- COLOR/FINISH:
- STEEL
- MATERIAL:
- 4140 STEEL
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- OE REPLACEMENT
- UNITS:
- KIT
- MODEL:
- 2-CYCLE
- PRODUCT NAME:
- BOTTOM END KIT
- STROKE LENGTH METRIC:
- STANDARD
$531.95
