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
-
Pro Circuit Ignition Cover for Kawasaki KLX110 2010-2025 ICK20110
PRO CIRCUIT
$63.00The ignition cover is one of the most exposed components on your KLX110, taking direct hits from roost, mud, and debris during aggressive riding. This Pro Circuit ignition cover shields your bike's...09401985- SKU:
- 09401985
- Availability:
- Ships Same Business Day
- Weight:
- 0.26 LBS
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- COLOR/FINISH:
- ANODIZED
- MATERIAL:
- BILLET ALUMINUM
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- IGNITION
$63.00 -
Pro Circuit Replacement O-Ring for 2004 Kawasaki KX250F and RM-Z250 PC4008-0401
PRO CIRCUIT
$5.95A failing water pump seal compromises cooling system integrity and risks catastrophic engine damage on the track or trail. The PRO CIRCUIT PC4008-0401 replacement O-ring restores OEM-spec sealing...09350003- SKU:
- 09350003
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- RIDING STYLE:
- OFF-ROAD
- APPLICATION:
- WATER PUMP
- PRODUCT NAME:
- O-RING
- UNITS:
- EACH
$5.95 -
Pro Circuit Clutch Cover Kawasaki KX250F 2004-2008 CCK04250
PRO CIRCUIT
$173.95The Pro Circuit Clutch Cover combines aerospace-grade durability with thermal management—critical for maintaining consistent clutch engagement during extended high-RPM sessions. T-6 aircraft aluminum...09400467- SKU:
- 09400467
- Availability:
- Ships Same Business Day
- Weight:
- 0.46 LBS
- COLOR/FINISH:
- BLACK
- MATERIAL:
- T-6 ALUMINUM
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- COLOR/FINISH:
- ALUMINUM
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
$173.95Qty in Cart: 0Quantity:Price:$173.95Subtotal: -
Pro Circuit Water Pump Cover with Impeller for Kawasaki KX250 2019-2020 WPK17250
PRO CIRCUIT
$239.95Engine cooling directly impacts your KX250's reliability and peak performance—especially under sustained high-RPM racing conditions. A stock water pump cover often allows cavitation and inefficient...09401611- SKU:
- 09401611
- Availability:
- Ships Same Business Day
- Weight:
- 0.71 LBS
- COLOR/FINISH:
- MACHINED
- PRODUCT NAME:
- COVER
- UNITS:
- SET
- TYPE:
- WATER PUMP
- COLOR/FINISH:
- ANODIZED
- MATERIAL:
- BILLET ALUMINUM
- RIDING STYLE:
- OFF-ROAD
$239.95 -
MOOSE RACING Countershaft Sprocket Seal Kit - KTM 25-4002
MOOSE RACING
$23.95The countershaft sprocket seal is a critical wear component that directly impacts drivetrain longevity and performance. Premature seal failure allows dirt and moisture ingress, leading to accelerated...09350429- SKU:
- 09350429
- Availability:
- Ships Same Business Day
- Weight:
- 0.21 LBS
- PRODUCT NAME:
- SEAL KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- APPLICATION:
- COUNTERSHAFT
$23.95Qty in Cart: 0Quantity:Price:$23.95Subtotal: -
MOOSE RACING Countershaft Sprocket Seal Kit - KTM 25-4004
MOOSE RACING
$39.95Countershaft seals are critical wear items that directly impact engine longevity and reliability. A failing seal allows transmission fluid to leak and contamination to enter, compromising shift...09350431- SKU:
- 09350431
- Availability:
- Ships Same Business Day
- Weight:
- 0.16 LBS
- APPLICATION:
- COUNTERSHAFT
- RIDING STYLE:
- STREET
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- SEAL KIT
- UNITS:
- KIT
$39.95Qty in Cart: 0Quantity:Price:$39.95Subtotal: -
MOOSE RACING Countershaft Sprocket Seal Kit - Yamaha 25-4022
MOOSE RACING
$23.95Countershaft seals are critical wear points that directly impact engine reliability and transmission performance. A failing seal allows contamination and fluid loss, compromising your engine's...09350447- SKU:
- 09350447
- Availability:
- Ships Same Business Day
- Weight:
- 0.19 LBS
- RIDING STYLE:
- OFF-ROAD
- APPLICATION:
- COUNTERSHAFT
- PRODUCT NAME:
- SEAL KIT
- UNITS:
- KIT
$23.95Qty in Cart: 0Quantity:Price:$23.95Subtotal: -
MOOSE RACING Inner Clutch Cover Gasket 816099
MOOSE RACING
$19.22A leaking clutch cover gasket compromises engine sealing and can lead to oil contamination and performance degradation. The MOOSE RACING Inner Clutch Cover Gasket (816099) delivers OEM-equivalent...09346121- SKU:
- 09346121
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH COVER
- PRODUCT NAME:
- GASKET
- UNITS:
- EACH
$19.22 -
MOOSE RACING Inner Clutch Cover Gasket 816130
MOOSE RACING
$8.55A failing clutch cover gasket leads to oil leakage, contamination, and potential engine damage—exactly what you can't afford during competition or a critical rebuild. The MOOSE RACING Inner Clutch...09346122- SKU:
- 09346122
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH COVER
- PRODUCT NAME:
- GASKET
- UNITS:
- EACH
$8.55 -
MOOSE RACING Inner Clutch Cover Gasket 816138
MOOSE RACING
$13.91Clutch cover gasket failures lead to oil seepage, loss of compression, and potential engine damage—especially critical if you're running a rebuilt or high-mileage engine. The MOOSE RACING Inner...09346123- SKU:
- 09346123
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH COVER
- UNITS:
- EACH
- PRODUCT NAME:
- GASKET
$13.91 -
MOOSE RACING Inner Clutch Cover Gasket 816149
MOOSE RACING
$12.69A leaking clutch cover gasket compromises engine sealing and invites oil contamination into your clutch assembly—a costly problem if left unaddressed. The MOOSE RACING Inner Clutch Cover Gasket...09346124- SKU:
- 09346124
- Availability:
- Ships Same Business Day
- Weight:
- 0.12 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH COVER
- UNITS:
- EACH
- PRODUCT NAME:
- GASKET
$12.69 -
MOOSE RACING Motor Gasket Kit with Seal - Husqvarna/KTM 811373
MOOSE RACING
$179.68A complete engine and transmission rebuild demands precision-fit gaskets and seals that won't compromise durability or reliability. This MOOSE RACING kit eliminates the frustration of sourcing...09345369- SKU:
- 09345369
- Availability:
- Ships Same Business Day
- Weight:
- 0.51 LBS
- PRODUCT NAME:
- GASKET
- UNITS:
- KIT
- TYPE:
- ENGINE
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
$179.68Qty in Cart: 0Quantity:Price:$179.68Subtotal: -
MOOSE RACING Motor Gasket Kit with Seal - Husqvarna/KTM 811374
MOOSE RACING
$145.13A complete engine and transmission rebuild demands precision-fit gaskets and seals—any compromise on fit or material quality risks oil leaks, compression loss, and premature wear. The MOOSE RACING...09345370- SKU:
- 09345370
- Availability:
- Ships Same Business Day
- Weight:
- 0.51 LBS
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- GASKET
- RIDING STYLE:
- STREET
- TYPE:
- ENGINE
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
$145.13 -
MOOSE RACING Motor Gasket Kit with Seal - Kawasaki 811485
MOOSE RACING
$200.43A complete engine and transmission rebuild demands precision-fit gaskets and seals you can trust—and OEM replacements often carry premium pricing that doesn't reflect the part's actual value. The...09345371- SKU:
- 09345371
- Availability:
- Ships Same Business Day
- Weight:
- 0.41 LBS
- TYPE:
- COMPLETE
- PRODUCT NAME:
- GASKET
- TYPE:
- ENGINE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$200.43 -
MOOSE RACING Motor Gasket Kit with Seal - KTM 811976
MOOSE RACING
$163.23A complete engine and transmission rebuild demands precision gaskets and seals that won't compromise your tolerances or leak under load. MOOSE Racing Motor Gasket Kits deliver OEM-equivalent...09345372- SKU:
- 09345372
- Availability:
- Ships Same Business Day
- Weight:
- 0.41 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- TYPE:
- ENGINE
- PRODUCT NAME:
- GASKET
- RIDING STYLE:
- STREET
- UNITS:
- KIT
$163.23 -
MOOSE RACING Complete Motor Gasket Kit - TC125 8080009
MOOSE RACING
$77.45A complete engine and transmission rebuild demands precision gaskets and seals that won't fail under load or high RPM cycles. The MOOSE RACING Complete Motor Gasket Kit eliminates the frustration of...09346437- SKU:
- 09346437
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- ENGINE
- TYPE:
- COMPLETE
- PRODUCT NAME:
- GASKET
$77.45 -
MOOSE RACING Complete Motor Gasket Kit without Seals - CRF450 8110035
MOOSE RACING
$150.96A complete engine rebuild demands precision gaskets that won't compromise reliability—OEM quality shouldn't require OEM pricing. This Moose Racing kit delivers comprehensive coverage for both engine...09346454- SKU:
- 09346454
- Availability:
- Ships Same Business Day
- Weight:
- 0.46 LBS
- PRODUCT NAME:
- GASKET
- RIDING STYLE:
- STREET
- TYPE:
- ENGINE
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
$150.96 -
MOOSE RACING Head Cover Gasket - Honda 819199
MOOSE RACING
$64.67Head cover gaskets are prone to deterioration over time, leading to oil leaks that compromise engine cleanliness and performance. OEM replacements come at a premium, but MOOSE Racing delivers...09346456- SKU:
- 09346456
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- PRODUCT NAME:
- GASKET
- MATERIAL:
- RUBBER
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- HEAD COVER
- UNITS:
- EACH
$64.67Qty in Cart: 0Quantity:Price:$64.67Subtotal: -
MOOSE RACING Valve Shim - 8.90 x 2.24 - 5 pack MSE5PK890224
MOOSE RACING
$10.95Maintaining precise valve clearances is critical to engine reliability and performance, and having the right shims on hand eliminates costly downtime during valve train service. MOOSE Racing valve...09261918- SKU:
- 09261918
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- STREET
- UNITS:
- 5 PACK
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- VALVE
- MATERIAL:
- ROLLED
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- RIDING STYLE:
- ATV
- VALVE SHIM THICKNESS METRIC:
- 2.24 MM
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
$10.95 -
MOOSE RACING Valve Shim - 8.90 x 2.32 - 5 pack MSE5PK890232
MOOSE RACING
$10.95Valve shim maintenance is critical to valve train precision, and having quality refill shims on hand eliminates downtime during adjustments. These MOOSE RACING shims are forged from 4140 cold-rolled...09261920- SKU:
- 09261920
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- STREET
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- 5 PACK
- MATERIAL:
- ROLLED
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
- VALVE SHIM THICKNESS METRIC:
- 2.32 MM
$10.95
