ATHENA Cylinder Head Insert ref. P400270308001B for KTM, HUSQVARNA and GAS GAS 2001-2025

The ATHENA P400270308001B cylinder head insert is designed for KTM EXC 125, SX 125, XCW 125, HUSQVARNA TC 125, TE 125, TX 125 and GAS GAS EC 125, MC 125 from 2001 to 2025. On a VHM cylinder head, the combustion chamber is an interchangeable insert (or dome). Changing the insert changes the chamber volume, and therefore the compression ratio, without modifying the head: you adapt the engine to the fuel, the terrain and your riding.

Specifications

• Brand: ATHENA
• Manufacturer part number: P400270308001B
• EAN code: 8056216242651
• Weight: 470 g
• Engine: 2-stroke

When to change the insert?

• Switch to a different fuel (98 or race fuel with a higher octane rating).
• Engine knocking (pinking) or running hot: compression too high for the fuel.
• You want more torque on tight or sandy terrain.

Change the insert when you change fuel or type of riding, or if the engine pinks. The insert's three dimensions (volume, piston height, squish) must match your engine.

Fitting tips

1. The insert is changed with the cylinder head removed.
2. Check that the actual height of your piston at top dead centre matches the figure given for the insert.
3. Replace the VHM head O-rings every time you take it apart.
4. Check the squish with solder wire before riding.
5. Tighten the head to the recommended torque, in a criss-cross pattern and in several stages, then fit a new spark plug.

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

• VHM head O-rings : see the selection
• Spark plug : NGK 2707 · NGK 3006
• Coolant : LIQUI MOLY 1 L · TWIN AIR

Frequently asked questions

Will it fit my original cylinder head?
No: VHM inserts only fit VHM cylinder heads.

Which version should I choose?
Choose according to your engine and fuel.

Compatibility

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

Fits:
GAS GAS EC 125 2025
GAS GAS MC 125 2025
GAS GAS MC 125 2024
GAS GAS MC 125 2023
GAS GAS MC 125 2022
GAS GAS MC 125 2021
HUSQVARNA TC 125 2025
HUSQVARNA TC 125 2024
HUSQVARNA TC 125 2023
HUSQVARNA TC 125 2022
HUSQVARNA TC 125 2021
HUSQVARNA TC 125 2020
HUSQVARNA TC 125 2019
HUSQVARNA TC 125 2018
HUSQVARNA TC 125 2017
HUSQVARNA TC 125 2016
HUSQVARNA TC 125 2015
HUSQVARNA TC 125 2014
HUSQVARNA TE 125 2025
HUSQVARNA TE 125 2016
HUSQVARNA TE 125 2015
HUSQVARNA TE 125 2014
HUSQVARNA TX 125 2019
HUSQVARNA TX 125 2018
HUSQVARNA TX 125 2017
KTM EXC 125 2016
KTM EXC 125 2015
KTM EXC 125 2014
KTM EXC 125 2013
KTM EXC 125 2012
KTM EXC 125 2011
KTM EXC 125 2010
KTM EXC 125 2009
KTM EXC 125 2008
KTM EXC 125 2007
KTM EXC 125 2006
KTM EXC 125 2005
KTM EXC 125 2004
KTM EXC 125 2003
KTM EXC 125 2002
KTM EXC 125 2001
KTM SX 125 2025
KTM SX 125 2024
KTM SX 125 2023
KTM SX 125 2022
KTM SX 125 2021
KTM SX 125 2020
KTM SX 125 2019
KTM SX 125 2018
KTM SX 125 2017
KTM SX 125 2016
KTM SX 125 2015
KTM SX 125 2014
KTM SX 125 2013
KTM SX 125 2012
KTM SX 125 2011
KTM SX 125 2010
KTM SX 125 2009
KTM SX 125 2008
KTM SX 125 2007
KTM SX 125 2006
KTM SX 125 2005
KTM SX 125 2004
KTM SX 125 2003
KTM SX 125 2002
KTM SX 125 2001
KTM XCW 125 2025
KTM XCW 125 2019