ATHENA Cylinder Head Insert for ATHENA cylinder kit for RIEJU, BETA, APRILIA and HM 1992-2024

The ATHENA S410105308003 cylinder head insert is designed for APRILIA MX 50, PEGASO 50, RX 50, RIEJU MRT 50, RR 50, BETA RR 50 and HM CRE 50 from 1992 to 2024. 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: S410105308003
• EAN code: 8051757185801
• Weight: 60 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

• ATHENA cylinder kit : ATHENA
• Piston : ATHENA
• VHM head O-rings : see the selection
• Spark plug : NGK 3961 · NGK 5722
• 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:
APRILIA MX 50 2004
APRILIA MX 50 2003
APRILIA MX 50 2002
APRILIA PEGASO 50 1997
APRILIA PEGASO 50 1996
APRILIA PEGASO 50 1995
APRILIA PEGASO 50 1994
APRILIA PEGASO 50 1993
APRILIA PEGASO 50 1992
APRILIA RX 50 2004
APRILIA RX 50 2003
APRILIA RX 50 2002
APRILIA RX 50 2001
APRILIA RX 50 2000
APRILIA RX 50 1999
APRILIA RX 50 1998
APRILIA RX 50 1997
APRILIA RX 50 1996
APRILIA RX 50 1995
BETA RR 50 2024
BETA RR 50 2023
BETA RR 50 2022
BETA RR 50 2021
BETA RR 50 2020
BETA RR 50 2019
BETA RR 50 2018
BETA RR 50 2017
BETA RR 50 2016
BETA RR 50 2015
BETA RR 50 2014
BETA RR 50 2013
BETA RR 50 2012
BETA RR 50 2011
BETA RR 50 2010
BETA RR 50 2009
BETA RR 50 2008
BETA RR 50 2007
BETA RR 50 2006
BETA RR 50 2005
BETA RR 50 2004
BETA RR 50 2003
BETA RR 50 2002
BETA RR 50 2001
BETA RR 50 2000
BETA RR 50 1999
BETA RR 50 1998
HM CRE 50 2017
HM CRE 50 2016
HM CRE 50 2015
HM CRE 50 2014
HM CRE 50 2013
HM CRE 50 2012
HM CRE 50 2011
HM CRE 50 2010
HM CRE 50 2009
HM CRE 50 2008
HM CRE 50 2007
HM CRE 50 2006
HM CRE 50 2005
HM CRE 50 2004
HM CRE 50 2003
HM CRE 50 2002
HM CRE 50 2001
HM CRE 50 2000
HM CRE 50 1999
RIEJU MRT 50 2024
RIEJU MRT 50 2023
RIEJU MRT 50 2022
RIEJU MRT 50 2021
RIEJU MRT 50 2020
RIEJU MRT 50 2019
RIEJU MRT 50 2018
RIEJU MRT 50 2017
RIEJU MRT 50 2016
RIEJU MRT 50 2015
RIEJU MRT 50 2014
RIEJU MRT 50 2013
RIEJU MRT 50 2012
RIEJU MRT 50 2011
RIEJU MRT 50 2010
RIEJU MRT 50 2009
RIEJU RR 50 2008
RIEJU RR 50 2007
RIEJU RR 50 2006
RIEJU RR 50 2005
RIEJU RR 50 2004
RIEJU RR 50 2003
RIEJU RR 50 2002
RIEJU RR 50 2001
RIEJU RR 50 2000
RIEJU RR 50 1999
RIEJU RR 50 1998
RIEJU RR 50 1997
RIEJU RR 50 1996
RIEJU RR 50 1995
RIEJU RR 50 1994
RIEJU RR 50 1993