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
-
BOYESEN Impeller/Waterpump Cover - Magnesium WPK-07M
BOYESEN
$194.95Engine cooling efficiency directly impacts performance, reliability, and longevity—especially under sustained racing conditions or high-load operation. The BOYESEN WPK-07M water pump cover and...09400263- SKU:
- 09400263
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- MAGNESIUM
- MATERIAL:
- ALUMINUM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- MODEL:
- SUPERCOOLER
- TYPE:
- WATER PUMP
- COLOR/FINISH:
- POWDER-COATED
- PRODUCT NAME:
- COVER AND IMPELLER KIT
$194.95 -
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...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...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
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
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,...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
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
HOT RODS Top End Bearing WB110
HOT RODS
$23.05The 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...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
$23.05 -
HOT RODS Top End Bearing WB111
HOT RODS
$23.05The 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...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
$23.05 -
HOT RODS Top End Bearing WB117
HOT RODS
$24.10The 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...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
$24.10 -
HOT RODS Top End Bearing WB118
HOT RODS
$24.10A 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...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
$24.10 -
HOT RODS Top End Bearing WB128
HOT RODS
$24.10The 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...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
$24.10 -
HOT RODS Top End Bearing WB139
HOT RODS
$20.95The 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...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
$20.95 -
HOT RODS Top End Bearing WB143
HOT RODS
$20.95The 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...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
$20.95 -
HOT RODS Top End Bearing WB144
HOT RODS
$24.10The 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...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
$24.10 -
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...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...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...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
$85.95 -
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...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...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...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...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...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
