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 - Zuma 50 P400485850002
ATHENA
MSRP: $20.95Now: $19.00Was: $20.95Superior-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...09341580- SKU:
- 09341580
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- UNITS:
- KIT
- ENGINE TYPE:
- -
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- COMPLETE
- RIDING STYLE:
- STREET
MSRP: $20.95Now: $19.00Was: $20.95 -
On Sale
ATHENA Gasket Kit - CRF250 P400210160007
ATHENA
MSRP: $104.95Now: $94.00Was: $104.95Kits 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 required09341054- SKU:
- 09341054
- Availability:
- Ships Same Business Day
- Weight:
- 0.14 LBS
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- BORE SIZE:
- 82,00 MM
- BORE SIZE METRIC:
- 82.00 MM
- UNITS:
- KIT
MSRP: $104.95Now: $94.00Was: $104.95 -
On Sale
ATHENA Gasket Kit - YZ125 P400485160010
ATHENA
MSRP: $58.95Now: $53.00Was: $58.95Kits 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 required09341055- SKU:
- 09341055
- Availability:
- Ships Same Business Day
- Weight:
- 0.12 LBS
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BORE SIZE:
- 54,00 MM
- TYPE:
- TOP END
- BORE SIZE METRIC:
- 54.00 MM
MSRP: $58.95Now: $53.00Was: $58.95 -
On Sale
ATHENA Gasket Kit - YZF450 P400485160013
ATHENA
MSRP: $122.95Now: $111.00Was: $122.95Kits 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 required09341057- SKU:
- 09341057
- Availability:
- Ships Same Business Day
- Weight:
- 0.18 LBS
- BORE SIZE:
- 98,00 MM
- BORE SIZE METRIC:
- 98.00 MM
- TYPE:
- TOP END
- RIDING STYLE:
- ATV
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
MSRP: $122.95Now: $111.00Was: $122.95 -
On Sale
ATHENA Top End Gasket Kit P400210600095
ATHENA
MSRP: $79.95Now: $72.00Was: $79.95Specifically 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...09340346- SKU:
- 09340346
- Availability:
- Ships Same Business Day
- Weight:
- 0.18 LBS
- MATERIAL:
- RUBBER
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- TOP END
- UNITS:
- KIT
MSRP: $79.95Now: $72.00Was: $79.95 -
On Sale
ATHENA Top End Gasket Kit P400250600016
ATHENA
MSRP: $86.95Now: $78.00Was: $86.95Specifically 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...09340347- SKU:
- 09340347
- Availability:
- Ships Same Business Day
- Weight:
- 0.18 LBS
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- MATERIAL:
- RUBBER
- TYPE:
- TOP END
- UNITS:
- KIT
MSRP: $86.95Now: $78.00Was: $86.95 -
On Sale
ATHENA Top End Gasket Kit P400485600118
ATHENA
MSRP: $26.95Now: $24.00Was: $26.95Specifically 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...09340348- SKU:
- 09340348
- Availability:
- Ships Same Business Day
- Weight:
- 0.13 LBS
- TYPE:
- TOP END
- PRODUCT NAME:
- GASKET KIT
- MATERIAL:
- RUBBER
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $26.95Now: $24.00Was: $26.95 -
On Sale
ATHENA Complete Gasket Kit - Honda P400210850095
ATHENA
MSRP: $150.95Now: $136.00Was: $150.95Superior-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...09340351- SKU:
- 09340351
- Availability:
- Ships Same Business Day
- Weight:
- 0.47 LBS
- PRODUCT NAME:
- GASKET KIT
- ENGINE TYPE:
- -
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
MSRP: $150.95Now: $136.00Was: $150.95 -
On Sale
ATHENA Complete Gasket Kit - Yamaha P400485850118
ATHENA
MSRP: $46.95Now: $42.00Was: $46.95Superior-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...09340353- SKU:
- 09340353
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- ENGINE TYPE:
- -
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
MSRP: $46.95Now: $42.00Was: $46.95 -
On Sale
ATHENA Gasket Kit - YZ450F/YFZ450 P400485160009
ATHENA
MSRP: $122.95Now: $111.00Was: $122.95Kits 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 required09340355- SKU:
- 09340355
- Availability:
- Ships Same Business Day
- Weight:
- 0.12 LBS
- BORE SIZE METRIC:
- 98.00 MM
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- ATV
- TYPE:
- TOP END
- UNITS:
- KIT
- BORE SIZE:
- 98,00 MM
MSRP: $122.95Now: $111.00Was: $122.95 -
On Sale
ATHENA Gasket Kit P400485160007
ATHENA
MSRP: $91.95Now: $83.00Was: $91.95Kits 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 required09340357- SKU:
- 09340357
- Availability:
- Ships Same Business Day
- Weight:
- 0.12 LBS
- PRODUCT NAME:
- GASKET KIT
- BORE SIZE METRIC:
- 83.00 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BORE SIZE:
- 83,00 MM
- TYPE:
- TOP END
MSRP: $91.95Now: $83.00Was: $91.95 -
On Sale
ATHENA Complete Gasket Kit - KTM P400060850143
ATHENA
MSRP: $46.95Now: $42.00Was: $46.95Superior-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...09340217- SKU:
- 09340217
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- UNITS:
- KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- ENGINE TYPE:
- -
- PRODUCT NAME:
- GASKET KIT
MSRP: $46.95Now: $42.00Was: $46.95Qty in Cart: 0Quantity:Price:MSRP: $46.95Now: $42.00Was: $46.95Subtotal: -
On Sale
ATHENA Cylinder Kit - KTM/Husqvarna P400270100023
ATHENA
MSRP: $974.95Now: $877.00Was: $974.95Kits 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 required09310865- SKU:
- 09310865
- Availability:
- Ships Same Business Day
- Weight:
- 3.91 LBS
- PRODUCT NAME:
- CYLINDER KIT
- STYLE:
- BIG BORE
- BORE SIZE METRIC:
- 82.00 MM
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- DISPLACEMENT:
- 276 CC
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- ENGINE TYPE:
- 4-STROKE
- MATERIAL:
- ALUMINUM
MSRP: $974.95Now: $877.00Was: $974.95 -
On Sale
ATHENA Cylinder Kit - Yamaha - Stock P400485100053
ATHENA
MSRP: $772.80Now: $696.00Was: $772.80Kits 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 required09310958- SKU:
- 09310958
- Availability:
- Ships Same Business Day
- Weight:
- 4.66 LBS
- BORE SIZE METRIC:
- 97.00 MM
- PRODUCT NAME:
- CYLINDER KIT
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- ENGINE TYPE:
- 4-STROKE
- MATERIAL:
- ALUMINUM
- DISPLACEMENT:
- 450 CC
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- STOCK BORE
- UNITS:
- KIT
MSRP: $772.80Now: $696.00Was: $772.80 -
On Sale
ATHENA Cylinder Kit - Yamaha - Stock P400485100067
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 required09310959- SKU:
- 09310959
- Availability:
- Ships Same Business Day
- Weight:
- 4.61 LBS
- PRODUCT NAME:
- CYLINDER KIT
- DISPLACEMENT:
- 450 CC
- STYLE:
- STOCK BORE
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BORE SIZE METRIC:
- 97.00 MM
- ENGINE TYPE:
- 4-STROKE
- MATERIAL:
- ALUMINUM
MSRP: $772.95Now: $696.00Was: $772.95Qty in Cart: 0Quantity:Price:MSRP: $772.95Now: $696.00Was: $772.95Subtotal: -
On Sale
ATHENA Cylinder Kit - Yamaha - Big Bore P400485100068
ATHENA
MSRP: $1,236.95Now: $1,113.00Was: $1,236.95Kits 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 required09310960- SKU:
- 09310960
- Availability:
- Ships Same Business Day
- Weight:
- 4.36 LBS
- ENGINE TYPE:
- 4-STROKE
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- CYLINDER KIT
- STYLE:
- BIG BORE
- UNITS:
- KIT
- BORE SIZE METRIC:
- 102.00 MM
- DISPLACEMENT:
- 496 CC
- MATERIAL:
- ALUMINUM
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
MSRP: $1,236.95Now: $1,113.00Was: $1,236.95 -
On Sale
ATHENA Top End Gasket Kit - KTM P400270600023
ATHENA
MSRP: $77.95Now: $70.00Was: $77.95Specifically 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...09341785- SKU:
- 09341785
- Availability:
- Ships Same Business Day
- Weight:
- 0.22 LBS
- UNITS:
- KIT
- TYPE:
- TOP END
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
MSRP: $77.95Now: $70.00Was: $77.95 -
On Sale
ATHENA Complete Gasket Kit - Husqvarna P400220850252
ATHENA
MSRP: $89.95Now: $81.00Was: $89.95Superior-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...09341824- SKU:
- 09341824
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- PRODUCT NAME:
- GASKET KIT
- ENGINE TYPE:
- -
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
- RIDING STYLE:
- STREET
MSRP: $89.95Now: $81.00Was: $89.95 -
On Sale
ATHENA Top End Gasket Kit - Honda P400210600183
ATHENA
MSRP: $46.95Now: $42.00Was: $46.95Specifically 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...09341970- SKU:
- 09341970
- Availability:
- Ships Same Business Day
- Weight:
- 0.16 LBS
- MATERIAL:
- RUBBER
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- TOP END
- PRODUCT NAME:
- GASKET KIT
MSRP: $46.95Now: $42.00Was: $46.95 -
On Sale
ATHENA Top End Gasket Kit - KTM P400270600013
ATHENA
MSRP: $24.95Now: $22.00Was: $24.95Specifically 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...09341982- SKU:
- 09341982
- Availability:
- Ships Same Business Day
- Weight:
- 0.08 LBS
- PRODUCT NAME:
- GASKET KIT
- MATERIAL:
- RUBBER
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- TOP END
MSRP: $24.95Now: $22.00Was: $24.95
