ATHENA Cylinder Base Gasket for KTM, HUSQVARNA and GAS GAS 2017-2023

The ATHENA cylinder base gasket is designed for KTM EXC 250, EXC 300, SX 250, XC 250, XC 300, XCW 250, XCW 300, GAS GAS EC 250, EC 300, EX 250, EX 300, MC 250 and HUSQVARNA TC 250, TE 250, TE 300, TX 300 from 2017 to 2023. The base gasket seals between the cylinder and the crankcase. Its thickness matters: it sets the height of the cylinder, and therefore the squish, the compression and, on a two-stroke, the port timing.

Key features

• Several thicknesses available for the same bike.
• The right tool for setting squish, compression and timing, according to Athena.

Specifications

• Brand: ATHENA
• Manufacturer part numbers: S410270006122, S410270006123, S410270006124, S410270006125, S410270006126
• Available versions: 0.20 mm: ref. S410270006122; 0.30 mm: ref. S410270006123; 0.40 mm: ref. S410270006124; 0.50 mm: ref. S410270006125; 0.75 mm: ref. S410270006126
• Engine: 2-stroke

Choosing the right thickness

Measure the thickness of the old gasket with a vernier caliper and fit the same, unless you are deliberately adjusting the squish. A thicker gasket increases the squish and lowers compression; a thinner one does the opposite. After any change of thickness, check the squish with solder wire.

When to replace it?

• Oil or coolant seeping at the base of the cylinder.
• Gasket crushed or torn on removal.

Every time the cylinder is removed: a crushed base gasket can't be reused.

Fitting tips

1. Clean the crankcase face and the base of the cylinder without scratching them.
2. Fit the gasket dry, centred on the studs.
3. Tighten the cylinder in a criss-cross pattern to the manufacturer's torque.
4. If you have changed the thickness, measure the squish before refitting the cylinder head with a new head gasket.

Why ATHENA?

Athena, an Italian company founded in 1973 near Vicenza, designs gaskets, pistons and cylinder kits for motorcycles. An OEM supplier to KTM, Ducati, Fantic, Piaggio and Triumph and a partner of the MXGP world championship, it develops its parts on the test bench and on the track with racing teams.

Spare parts and items to plan

• Top-end gasket kit : ATHENA M752007800094 · ATHENA M752010500094
• Piston : ATHENA · METEOR
• Piston rings : ATHENA · VERTEX
• Coolant : LIQUI MOLY 1 L · TWIN AIR

Frequently asked questions

Which thickness should I choose?
The same as your original gasket, unless you are deliberately adjusting the squish. Thicknesses available: 0.20 mm, 0.30 mm, 0.40 mm, 0.50 mm, 0.75 mm.

Should the other gaskets be replaced?
Yes, as soon as the cylinder is removed: a top end gasket kit includes all the gaskets that need replacing.

Compatibility

Check the exact model and year of your bike in the list below before ordering.

Fits:
GAS GAS EC 250 2023
GAS GAS EC 250 2022
GAS GAS EC 250 2021
GAS GAS EC 300 2023
GAS GAS EC 300 2022
GAS GAS EC 300 2021
GAS GAS EX 250 2023
GAS GAS EX 250 2022
GAS GAS EX 300 2023
GAS GAS EX 300 2022
GAS GAS EX 300 2021
GAS GAS MC 250 2023
GAS GAS MC 250 2022
HUSQVARNA TC 250 2022
HUSQVARNA TC 250 2021
HUSQVARNA TC 250 2020
HUSQVARNA TC 250 2019
HUSQVARNA TC 250 2018
HUSQVARNA TC 250 2017
HUSQVARNA TE 250 2023
HUSQVARNA TE 250 2022
HUSQVARNA TE 250 2021
HUSQVARNA TE 250 2020
HUSQVARNA TE 250 2019
HUSQVARNA TE 250 2018
HUSQVARNA TE 250 2017
HUSQVARNA TE 300 2023
HUSQVARNA TE 300 2022
HUSQVARNA TE 300 2021
HUSQVARNA TE 300 2020
HUSQVARNA TE 300 2019
HUSQVARNA TE 300 2018
HUSQVARNA TE 300 2017
HUSQVARNA TX 300 2022
HUSQVARNA TX 300 2021
HUSQVARNA TX 300 2020
HUSQVARNA TX 300 2019
HUSQVARNA TX 300 2018
HUSQVARNA TX 300 2017
KTM EXC 250 2023
KTM EXC 250 2022
KTM EXC 250 2021
KTM EXC 250 2020
KTM EXC 250 2019
KTM EXC 250 2018
KTM EXC 250 2017
KTM EXC 300 2023
KTM EXC 300 2022
KTM EXC 300 2021
KTM EXC 300 2020
KTM EXC 300 2019
KTM EXC 300 2018
KTM EXC 300 2017
KTM SX 250 2022
KTM SX 250 2021
KTM SX 250 2020
KTM SX 250 2019
KTM SX 250 2018
KTM SX 250 2017
KTM XC 250 2022
KTM XC 250 2021
KTM XC 250 2020
KTM XC 250 2019
KTM XC 250 2018
KTM XC 250 2017
KTM XC 300 2022
KTM XC 300 2021
KTM XC 300 2020
KTM XC 300 2019
KTM XC 300 2018
KTM XC 300 2017
KTM XCW 250 2023
KTM XCW 250 2022
KTM XCW 250 2021
KTM XCW 250 2020
KTM XCW 250 2019
KTM XCW 250 2018
KTM XCW 250 2017
KTM XCW 300 2023
KTM XCW 300 2022
KTM XCW 300 2021
KTM XCW 300 2020
KTM XCW 300 2019
KTM XCW 300 2018
KTM XCW 300 2017