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
-
On Sale
ATHENA Complete Gasket Kit - Suzuki P400510850034
ATHENA
MSRP: $42.95Now: $39.00Was: $42.95Superior-quality gasket sets from Athena, Head gaskets feature rubber-coated spring steel construction, Soft steel base gaskets are rubber coated, Steel core materials feature high springback and superior tensile strength, Revolutionary transparent...09340207- SKU:
- 09340207
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- PRODUCT NAME:
- GASKET KIT
- ENGINE TYPE:
- -
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
MSRP: $42.95Now: $39.00Was: $42.95Qty in Cart: 0Quantity:Price:MSRP: $42.95Now: $39.00Was: $42.95Subtotal: -
On Sale
ATHENA Top End Gasket Kit P400510600034
ATHENA
MSRP: $21.95Now: $20.00Was: $21.95Specifically designed for the pro, semi-pro and amateur rider who freshens up their engine prior to a race or during midseason. Gives the rider a choice of using standard gas with stock compression, or race gas with a higher compression. Kits do not...09340210- SKU:
- 09340210
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- PRODUCT NAME:
- GASKET KIT
- ENGINE TYPE:
- 2-STROKE
- MATERIAL:
- RUBBER
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
MSRP: $21.95Now: $20.00Was: $21.95 -
On Sale
ATHENA Top End Gasket Kit P400510600035
ATHENA
MSRP: $42.95Now: $39.00Was: $42.95Specifically designed for the pro, semi-pro and amateur rider who freshens up their engine prior to a race or during midseason. Gives the rider a choice of using standard gas with stock compression, or race gas with a higher compression. Kits do not...09340211- SKU:
- 09340211
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- ENGINE TYPE:
- 2-STROKE
- MATERIAL:
- RUBBER
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- TOP END
MSRP: $42.95Now: $39.00Was: $42.95Qty in Cart: 0Quantity:Price:MSRP: $42.95Now: $39.00Was: $42.95Subtotal: -
On Sale
ATHENA Complete Gasket Kit - Yamaha P400485850053
ATHENA
MSRP: $163.95Now: $148.00Was: $163.95Superior-quality gasket sets from Athena, Head gaskets feature rubber-coated spring steel construction, Soft steel base gaskets are rubber coated, Steel core materials feature high springback and superior tensile strength, Revolutionary transparent...09340213- SKU:
- 09340213
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
MSRP: $163.95Now: $148.00Was: $163.95 -
On Sale
ATHENA Complete Gasket Kit - KTM P400270850003
ATHENA
MSRP: $28.95Now: $26.00Was: $28.95Superior-quality gasket sets from Athena, Head gaskets feature rubber-coated spring steel construction, Soft steel base gaskets are rubber coated, Steel core materials feature high springback and superior tensile strength, Revolutionary transparent...09340216- SKU:
- 09340216
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
- ENGINE TYPE:
- -
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
MSRP: $28.95Now: $26.00Was: $28.95 -
On Sale
ATHENA Cylinder Kit - CRF230F P400210100054
ATHENA
MSRP: $416.95Now: $375.00Was: $416.95Kits include aluminum cylinder with nickel-carbide coating designed with larger water jackets, Forged piston with molybdenum coating, Special gasket kit, Easy-to-follow step-by-step installation instructions, All are bolt-on; no machining required09310662- SKU:
- 09310662
- Availability:
- Ships Same Business Day
- Weight:
- 4.75 LBS
- STYLE:
- BIG BORE
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- ENGINE TYPE:
- 4-STROKE
- BORE SIZE METRIC:
- 67.00 MM
- MATERIAL:
- ALUMINUM
- DISPLACEMENT:
- 233 CC
- PRODUCT NAME:
- CYLINDER KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $416.95Now: $375.00Was: $416.95 -
On Sale
ATHENA Cylinder Kit - Suzuki RM-Z450 P400510100027
ATHENA
MSRP: $772.95Now: $696.00Was: $772.95Kits include aluminum cylinder with nickel-carbide coating designed with larger water jackets, Forged piston with molybdenum coating, Special gasket kit, Easy-to-follow step-by-step installation instructions, All are bolt-on; no machining required09310678- SKU:
- 09310678
- Availability:
- Ships Same Business Day
- Weight:
- 4.05 LBS
- DISPLACEMENT:
- 450 CC
- MATERIAL:
- ALUMINUM
- STYLE:
- STOCK BORE
- PRODUCT NAME:
- CYLINDER KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- ENGINE TYPE:
- 4-STROKE
- BORE SIZE METRIC:
- 96.00 MM
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
MSRP: $772.95Now: $696.00Was: $772.95 -
On Sale
ATHENA Cylinder Kit - Suzuki RM-Z450 P400510100028
ATHENA
MSRP: $1,151.95Now: $1,037.00Was: $1,151.95Kits include aluminum cylinder with nickel-carbide coating designed with larger water jackets, Forged piston with molybdenum coating, Special gasket kit, Easy-to-follow step-by-step installation instructions, All are bolt-on; no machining required09310679- SKU:
- 09310679
- Availability:
- Ships Same Business Day
- Weight:
- 3.80 LBS
- DISPLACEMENT:
- 490 CC
- MATERIAL:
- ALUMINUM
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- ENGINE TYPE:
- 4-STROKE
- BORE SIZE METRIC:
- 100.00 MM
- PRODUCT NAME:
- CYLINDER KIT
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- BIG BORE
- UNITS:
- KIT
MSRP: $1,151.95Now: $1,037.00Was: $1,151.95Qty in Cart: 0Quantity:Price:MSRP: $1,151.95Now: $1,037.00Was: $1,151.95Subtotal: -
On Sale
ATHENA Cylinder Kit - Honda - Stock P400210100066
ATHENA
MSRP: $772.95Now: $696.00Was: $772.95Kits include aluminum cylinder with nickel-carbide coating designed with larger water jackets, Forged piston with molybdenum coating, Special gasket kit, Easy-to-follow step-by-step installation instructions, All are bolt-on; no machining required09310955- SKU:
- 09310955
- Availability:
- Ships Same Business Day
- Weight:
- 3.36 LBS
- DISPLACEMENT:
- 250 CC
- MATERIAL:
- ALUMINUM
- STYLE:
- STOCK BORE
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- ENGINE TYPE:
- 4-STROKE
- BORE SIZE METRIC:
- 79.00 MM
- PRODUCT NAME:
- CYLINDER KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $772.95Now: $696.00Was: $772.95 -
On Sale
ATHENA Cylinder Kit - Honda - Big Bore P400210100067
ATHENA
MSRP: $1,166.95Now: $1,050.00Was: $1,166.95Kits include aluminum cylinder with nickel-carbide coating designed with larger water jackets, Forged piston with molybdenum coating, Special gasket kit, Easy-to-follow step-by-step installation instructions, All are bolt-on; no machining required09310956- SKU:
- 09310956
- Availability:
- Ships Same Business Day
- Weight:
- 3.71 LBS
- DISPLACEMENT:
- 289 CC
- MATERIAL:
- ALUMINUM
- BORE SIZE METRIC:
- 82.00 MM
- PRODUCT NAME:
- CYLINDER KIT
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- BIG BORE
- UNITS:
- KIT
- ENGINE TYPE:
- 4-STROKE
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
MSRP: $1,166.95Now: $1,050.00Was: $1,166.95 -
On Sale
ATHENA Cylinder Kit - Honda - Stock P400210100059
ATHENA
MSRP: $772.95Now: $696.00Was: $772.95Kits include aluminum cylinder with nickel-carbide coating designed with larger water jackets, Forged piston with molybdenum coating, Special gasket kit, Easy-to-follow step-by-step installation instructions, All are bolt-on; no machining required09310957- SKU:
- 09310957
- Availability:
- Ships Same Business Day
- Weight:
- 4.06 LBS
- PRODUCT NAME:
- CYLINDER KIT
- DISPLACEMENT:
- 450 CC
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- STOCK BORE
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- UNITS:
- KIT
- BORE SIZE METRIC:
- 96.00 MM
- ENGINE TYPE:
- 4-STROKE
- MATERIAL:
- ALUMINUM
MSRP: $772.95Now: $696.00Was: $772.95 -
On Sale
ATHENA Cylinder Kit - Kawasaki - Stock P400250100022
ATHENA
MSRP: $772.95Now: $696.00Was: $772.95Kits include aluminum cylinder with nickel-carbide coating designed with larger water jackets, Forged piston with molybdenum coating, Special gasket kit, Easy-to-follow step-by-step installation instructions, All are bolt-on; no machining required09310961- SKU:
- 09310961
- Availability:
- Ships Same Business Day
- Weight:
- 4.41 LBS
- ENGINE TYPE:
- 4-STROKE
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- BORE SIZE METRIC:
- 96.00 MM
- DISPLACEMENT:
- 450 CC
- MATERIAL:
- ALUMINUM
- STYLE:
- STOCK BORE
- PRODUCT NAME:
- CYLINDER KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $772.95Now: $696.00Was: $772.95Qty in Cart: 0Quantity:Price:MSRP: $772.95Now: $696.00Was: $772.95Subtotal: -
On Sale
ATHENA Cylinder Kit - Yamaha - Stock P400485100076
ATHENA
MSRP: $1,019.95Now: $918.00Was: $1,019.95Kits include aluminum cylinder with nickel-carbide coating designed with larger water jackets, Forged piston with molybdenum coating, Special gasket kit, Easy-to-follow step-by-step installation instructions, All are bolt-on; no machining required09310975- SKU:
- 09310975
- Availability:
- Ships Same Business Day
- Weight:
- 4.86 LBS
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- ENGINE TYPE:
- 2-STROKE
- MATERIAL:
- ALUMINUM
- STYLE:
- STOCK BORE
- BORE SIZE METRIC:
- 47.50 MM
- DISPLACEMENT:
- 85 CC
- PRODUCT NAME:
- CYLINDER KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $1,019.95Now: $918.00Was: $1,019.95 -
On Sale
ATHENA Piston Kit S4C04750005A
ATHENA
MSRP: $124.95Now: $112.00Was: $124.95Two-stroke pistons are made from 4032 silicium, Four-stroke pistons are made from 2618 silicium - the same material used to produce Formula 1 pistons, Both include 3% copper in materials for better heat resistance, All pistons are forged using a...09310976- SKU:
- 09310976
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- 4032 ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- COMPRESSION RATIO IMPERIAL:
- STOCK
- UNITS:
- KIT
- PRODUCT NAME:
- PISTON KIT
- TYPE:
- B
- BORE SIZE METRIC:
- 47.45 MM
MSRP: $124.95Now: $112.00Was: $124.95 -
On Sale
ATHENA Gasket Kit - KX125LC P400250160008
ATHENA
MSRP: $118.95Now: $107.00Was: $118.95Kits include aluminum cylinder with nickel-carbide coating designed with larger water jackets, Forged piston with molybdenum coating, Special gasket kit, Easy-to-follow step-by-step installation instructions, All are bolt-on; no machining required09342135- SKU:
- 09342135
- Availability:
- Ships Same Business Day
- Weight:
- 0.24 LBS
- BORE SIZE:
- 58,00 MM
- DISPLACEMENT:
- 144 CC
- UNITS:
- KIT
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 58.00 MM
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- TOP END
MSRP: $118.95Now: $107.00Was: $118.95 -
On Sale
ATHENA Gasket Kit - KX250F P400250160010
ATHENA
MSRP: $57.95Now: $52.00Was: $57.95Kits include aluminum cylinder with nickel-carbide coating designed with larger water jackets, Forged piston with molybdenum coating, Special gasket kit, Easy-to-follow step-by-step installation instructions, All are bolt-on; no machining required09342136- SKU:
- 09342136
- Availability:
- Ships Same Business Day
- Weight:
- 0.17 LBS
- DISPLACEMENT:
- 290 CC
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- TOP END
- BORE SIZE:
- 83,00 MM
- BORE SIZE METRIC:
- 83.00 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $57.95Now: $52.00Was: $57.95 -
On Sale
ATHENA Gasket Kit - KXF450 P400250160012
ATHENA
MSRP: $98.95Now: $89.00Was: $98.95Kits include aluminum cylinder with nickel-carbide coating designed with larger water jackets, Forged piston with molybdenum coating, Special gasket kit, Easy-to-follow step-by-step installation instructions, All are bolt-on; no machining required09342552- SKU:
- 09342552
- Availability:
- Ships Same Business Day
- Weight:
- 0.22 LBS
- TYPE:
- TOP END
- BORE SIZE:
- 100,00 MM
- PRODUCT NAME:
- GASKET KIT
- BORE SIZE METRIC:
- 100.00 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $98.95Now: $89.00Was: $98.95 -
On Sale
ATHENA Top End Gasket Kit - KTM P400270600047
ATHENA
MSRP: $73.95Now: $67.00Was: $73.95Specifically designed for the pro, semi-pro and amateur rider who freshens up their engine prior to a race or during midseason. Gives the rider a choice of using standard gas with stock compression, or race gas with a higher compression. Kits do not...09341981- SKU:
- 09341981
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- PRODUCT NAME:
- GASKET KIT
- MATERIAL:
- RUBBER
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- TOP END
MSRP: $73.95Now: $67.00Was: $73.95Qty in Cart: 0Quantity:Price:MSRP: $73.95Now: $67.00Was: $73.95Subtotal: -
On Sale
ATHENA Race Gasket Kit - RM65/KX65 R2506-008
ATHENA
MSRP: $25.95Now: $23.00Was: $25.95Specifically designed for the pro, semi-pro and amateur rider who freshens up their engine prior to a race or during mid-season, Kits include a top-of-the line MLSS head gasket and two or more premium-quality base gaskets of different thicknesses to...09342816- SKU:
- 09342816
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- MATERIAL:
- RUBBER
- TYPE:
- TOP END
- UNITS:
- KIT
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- GASKET KIT
- STYLE:
- RACE
MSRP: $25.95Now: $23.00Was: $25.95 -
On Sale
ATHENA Race Gasket Kit - KX250F R2506-047
ATHENA
MSRP: $61.95Now: $56.00Was: $61.95Specifically designed for the pro, semi-pro and amateur rider who freshens up their engine prior to a race or during mid-season, Kits include a top-of-the line MLSS head gasket and two or more premium-quality base gaskets of different thicknesses to...09342819- SKU:
- 09342819
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- STYLE:
- RACE
- TYPE:
- TOP END
- PRODUCT NAME:
- GASKET KIT
- MATERIAL:
- RUBBER
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $61.95Now: $56.00Was: $61.95
