ATHENA Cast Piston for ATHENA cylinder for standard bore cylinder kit for BETA, RIEJU and APRILIA 1995-2024

ATHENA offers this piston kit for ATHENA cylinder for BETA RR 50, RIEJU MRT 50 and APRILIA MX 50, RX 50 1995-2024. The piston slides in the cylinder and takes the force of the air-fuel combustion, passing it to the connecting rod and crankshaft.

Why a cast piston?

A cast piston is moulded from a high-silicon aluminium alloy, then machined.

• Low expansion: it runs with a tight clearance, stays quiet when cold and warms up quickly.
• Durability: an excellent choice for a stock engine used for leisure or enduro.
• Price: more affordable than a forged piston.
• Good to know: it copes less well with overheating and extreme revs than a forged one.

Why choose ATHENA?

Athena, the Italian manufacturer founded in 1973, is an original-equipment supplier to manufacturers such as KTM and Ducati: the same standards for your replacement parts.

When should you replace the piston on your BETA RR 50?

Harder starting, loss of power, blue smoke, oil consumption or a knock when cold: these are the signs of a tired top end.

No manufacturer hour figure for this model. Cross-Mania guideline: compression check every 15 h in hard use and every 30 h for leisure.

Specifications and fitting tips

• Engine: 2-stroke
• Manufacturer part numbers: S4C04000007A (A), S4C04000007B (B), S4C04000007C (C)

Available in several sizes: choose the one that matches your cylinder (stamped size or measured bore). Diameters: A = 39.96 mm, B = 39.97 mm, C = 39.98 mm.

Spare parts and items to plan

• Top-end gasket kit : ATHENA S410130006012 · ATHENA S410130001004
• Small end needle bearing : ATHENA
• Spark plug : NGK 3961 · NGK 5722
• Coolant : LIQUI MOLY 1 L · TWIN AIR
• 2-stroke oil : LIQUI MOLY 1 L 3065 · LIQUI MOLY 1 L 3063

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 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
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