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 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...09310961- 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...09310975- 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: $1,019.95Qty in Cart: 0Quantity:Price:MSRP: $1,019.95Now: $918.00Was: $1,019.95Subtotal: -
On Sale
ATHENA Piston Kit S4C04750005A
ATHENA
MSRP: $115.95Now: $112.00Was: $115.95Two-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...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: $115.95Now: $112.00Was: $115.95 -
On Sale
ATHENA Gasket Kit - KX125LC P400250160008
ATHENA
MSRP: $110.95Now: $107.00Was: $110.95Kits 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...09342135- 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: $110.95Now: $107.00Was: $110.95 -
On Sale
ATHENA Gasket Kit - KX250F P400250160010
ATHENA
MSRP: $60.95Now: $52.00Was: $60.95Kits 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...09342136- 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: $60.95Now: $52.00Was: $60.95 -
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...09342552- 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: $98.95Qty in Cart: 0Quantity:Price:MSRP: $98.95Now: $89.00Was: $98.95Subtotal: -
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,...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...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...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 -
On Sale
ATHENA Top End Gasket Kit - Honda P400210600182
ATHENA
MSRP: $52.95Now: $48.00Was: $52.95Specifically 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,...09342902- SKU:
- 09342902
- Availability:
- Ships Same Business Day
- Weight:
- 0.17 LBS
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- TOP END
MSRP: $52.95Now: $48.00Was: $52.95Qty in Cart: 0Quantity:Price:MSRP: $52.95Now: $48.00Was: $52.95Subtotal: -
On Sale
ATHENA Top End Gasket Kit - Kawasaki P400250600104
ATHENA
MSRP: $38.95Now: $35.00Was: $38.95Specifically 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,...09342904- SKU:
- 09342904
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
MSRP: $38.95Now: $35.00Was: $38.95Qty in Cart: 0Quantity:Price:MSRP: $38.95Now: $35.00Was: $38.95Subtotal: -
On Sale
ATHENA Top End Gasket Kit - KTM P400270600043
ATHENA
MSRP: $53.95Now: $49.00Was: $53.95Specifically 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,...09342905- SKU:
- 09342905
- Availability:
- Ships Same Business Day
- Weight:
- 0.04 LBS
- RIDING STYLE:
- OFF-ROAD
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- TOP END
- UNITS:
- KIT
MSRP: $53.95Now: $49.00Was: $53.95 -
On Sale
ATHENA Gasket Kit - YZ85 P400485160023
ATHENA
MSRP: $40.95Now: $40.00Was: $40.95Kits 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...09342912- SKU:
- 09342912
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- TYPE:
- TOP END
- BORE SIZE METRIC:
- 53.00 MM
- PRODUCT NAME:
- GASKET KIT
- BORE SIZE:
- 53,00 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $40.95Now: $40.00Was: $40.95 -
On Sale
ATHENA Complete Gasket Kit - Honda P400210850288
ATHENA
MSRP: $149.95Now: $135.00Was: $149.95Superior-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...09342968- SKU:
- 09342968
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
- ENGINE TYPE:
- -
- PRODUCT NAME:
- GASKET KIT
MSRP: $149.95Now: $135.00Was: $149.95Qty in Cart: 0Quantity:Price:MSRP: $149.95Now: $135.00Was: $149.95Subtotal: -
On Sale
ATHENA Top End Gasket Kit - Yamaha P400485600078
ATHENA
MSRP: $117.95Now: $106.00Was: $117.95Specifically 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,...09343033- SKU:
- 09343033
- Availability:
- Ships Same Business Day
- Weight:
- 0.26 LBS
- RIDING STYLE:
- ATV
- TYPE:
- TOP END
- UNITS:
- KIT
- MATERIAL:
- SILICONE
- PRODUCT NAME:
- GASKET KIT
MSRP: $117.95Now: $106.00Was: $117.95Qty in Cart: 0Quantity:Price:MSRP: $117.95Now: $106.00Was: $117.95Subtotal: -
On Sale
ATHENA Complete Gasket Kit - Kawasaki P400250850029
ATHENA
MSRP: $140.95Now: $127.00Was: $140.95Superior-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...09343042- SKU:
- 09343042
- Availability:
- Ships Same Business Day
- Weight:
- 0.39 LBS
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- ATV
- TYPE:
- COMPLETE
- ENGINE TYPE:
- -
- UNITS:
- KIT
MSRP: $140.95Now: $127.00Was: $140.95Qty in Cart: 0Quantity:Price:MSRP: $140.95Now: $127.00Was: $140.95Subtotal: -
On Sale
ATHENA Complete Gasket Kit - Yamaha P400485850156
ATHENA
MSRP: $182.95Now: $157.00Was: $182.95Superior-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...09343046- SKU:
- 09343046
- Availability:
- Ships Same Business Day
- Weight:
- 0.46 LBS
- UNITS:
- KIT
- ENGINE TYPE:
- -
- RIDING STYLE:
- UTV
- TYPE:
- COMPLETE
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- ATV
MSRP: $182.95Now: $157.00Was: $182.95 -
On Sale
ATHENA Gasket Kit - YZ125 LC - 58 mm P400485160015
ATHENA
MSRP: $75.95Now: $74.00Was: $75.95Kits 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...09343117- SKU:
- 09343117
- Availability:
- Ships Same Business Day
- Weight:
- 0.19 LBS
- DISPLACEMENT:
- 144 CC
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BORE SIZE:
- 58,00 MM
- BORE SIZE METRIC:
- 58.00 MM
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- TOP END
MSRP: $75.95Now: $74.00Was: $75.95 -
On Sale
ATHENA Top End Gasket Kit - Yamaha P400485600187
ATHENA
MSRP: $91.95Now: $83.00Was: $91.95Specifically 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,...09343171- SKU:
- 09343171
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- GASKET KIT
MSRP: $91.95Now: $83.00Was: $91.95 -
On Sale
ATHENA Complete Gasket Kit - Yamaha P400485900187
ATHENA
MSRP: $207.95Now: $187.00Was: $207.95Superior-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...09343172- SKU:
- 09343172
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
- ENGINE TYPE:
- 4-STROKE
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
MSRP: $207.95Now: $187.00Was: $207.95Qty in Cart: 0Quantity:Price:MSRP: $207.95Now: $187.00Was: $207.95Subtotal:
