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 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, or race gas with a higher compression. Kits do not...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, or race gas with a higher compression. Kits do not...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: $38.95 -
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, or race gas with a higher compression. Kits do not...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: $44.95Now: $40.00Was: $44.95Kits 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 required09342912- 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: $44.95Now: $40.00Was: $44.95 -
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 superior tensile strength, Revolutionary transparent...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, or race gas with a higher compression. Kits do not...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 superior tensile strength, Revolutionary transparent...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: $140.95 -
On Sale
ATHENA Complete Gasket Kit - Yamaha P400485850156
ATHENA
MSRP: $173.95Now: $157.00Was: $173.95Superior-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...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: $173.95Now: $157.00Was: $173.95 -
On Sale
ATHENA Gasket Kit - YZ125 LC - 58 mm P400485160015
ATHENA
MSRP: $81.95Now: $74.00Was: $81.95Kits 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 required09343117- 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: $81.95Now: $74.00Was: $81.95 -
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, or race gas with a higher compression. Kits do not...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 superior tensile strength, Revolutionary transparent...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: -
On Sale
ATHENA Complete Gasket Kit - Honda P400210850304
ATHENA
MSRP: $87.95Now: $79.00Was: $87.95Superior-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...09344819- SKU:
- 09344819
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- PRODUCT NAME:
- GASKET KIT
- ENGINE TYPE:
- -
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
MSRP: $87.95Now: $79.00Was: $87.95 -
On Sale
ATHENA Complete Gasket Kit - Polaris P400485850006
ATHENA
MSRP: $15.95Now: $14.00Was: $15.95Superior-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...09344887- SKU:
- 09344887
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- TYPE:
- COMPLETE
- UNITS:
- KIT
- ENGINE TYPE:
- -
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- ATV
MSRP: $15.95Now: $14.00Was: $15.95Qty in Cart: 0Quantity:Price:MSRP: $15.95Now: $14.00Was: $15.95Subtotal: -
On Sale
ATHENA Complete Gasket Kit - Polaris P400427870017
ATHENA
MSRP: $162.95Now: $147.00Was: $162.95Superior-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...09344898- SKU:
- 09344898
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- ATV
- ENGINE TYPE:
- -
- TYPE:
- COMPLETE
- UNITS:
- KIT
MSRP: $162.95Now: $147.00Was: $162.95 -
On Sale
ATHENA Gasket Kit - TRX450R P400210160014
ATHENA
MSRP: $149.95Now: $135.00Was: $149.95Kits 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 required09344911- SKU:
- 09344911
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- BORE SIZE METRIC:
- 100.00 MM
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- ATV
- TYPE:
- TOP END
- UNITS:
- KIT
- BORE SIZE:
- 100,00 MM
MSRP: $149.95Now: $135.00Was: $149.95Qty in Cart: 0Quantity:Price:MSRP: $149.95Now: $135.00Was: $149.95Subtotal: -
On Sale
ATHENA Water Pump Gasket Kit - Yamaha P400485470001
ATHENA
MSRP: $44.95Now: $40.00Was: $44.95Include water pump gasket, clutch cover gasket, water pump shaft oil seals and washers, Kit contents will vary slightly based on application, Kits do not contain replacement bearings09345166- SKU:
- 09345166
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
- UNITS:
- KIT
MSRP: $44.95Now: $40.00Was: $44.95Qty in Cart: 0Quantity:Price:MSRP: $44.95Now: $40.00Was: $44.95Subtotal: -
On Sale
ATHENA Cylinder Kit - CRF150R - 69mm P400210100023
ATHENA
MSRP: $698.95Now: $629.00Was: $698.95Kits 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 required09310307- SKU:
- 09310307
- Availability:
- Ships Same Business Day
- Weight:
- 3.14 LBS
- DISPLACEMENT:
- 163.5 CC
- ENGINE TYPE:
- 4-STROKE
- BORE SIZE METRIC:
- 69.00 MM
- PRODUCT NAME:
- CYLINDER KIT
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- BIG BORE
- UNITS:
- KIT
- MATERIAL:
- ALUMINUM
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
MSRP: $698.95Now: $629.00Was: $698.95 -
On Sale
ATHENA Cylinder Kit - YZ250 - 72mm P400485100042
ATHENA
MSRP: $1,784.95Now: $1,606.00Was: $1,784.95Kits 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 required09310440- SKU:
- 09310440
- Availability:
- Ships Same Business Day
- Weight:
- 9.00 LBS
- BORE SIZE METRIC:
- 72.00 MM
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- ENGINE TYPE:
- 2-STROKE
- DISPLACEMENT:
- 293 CC
- MATERIAL:
- ALUMINUM
- PRODUCT NAME:
- CYLINDER KIT
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- BIG BORE
- UNITS:
- KIT
MSRP: $1,784.95Now: $1,606.00Was: $1,784.95 -
On Sale
ATHENA Cylinder Kit - YZ85 - 105CC P400485100038
ATHENA
MSRP: $976.95Now: $879.00Was: $976.95Kits 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 required09310473- SKU:
- 09310473
- Availability:
- Ships Same Business Day
- Weight:
- 4.33 LBS
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- UNITS:
- KIT
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- CYLINDER KIT
- STYLE:
- BIG BORE
- BORE SIZE METRIC:
- 53.00 MM
- DISPLACEMENT:
- 105 CC
- ENGINE TYPE:
- 2-STROKE
- MATERIAL:
- ALUMINUM
MSRP: $976.95Now: $879.00Was: $976.95 -
On Sale
ATHENA Cylinder Gasket Kit - YZ125 P400485160003
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 required400485160003- SKU:
- 400485160003
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
MSRP: $57.95Now: $52.00Was: $57.95
