ATHENA Racing Complete Crankshaft ref. S410130320001 for BETA RR 50, RIEJU MRT 50 and APRILIA MX 50, RX 50 1995-2024

On APRILIA MX 50, RX 50, BETA RR 50 and RIEJU MRT 50 from 1995 to 2024, the ATHENA Racing S410130320001 complete crankshaft fits in place of the original part. The centrepiece of the bottom end, the crankshaft carries the connecting rod and takes every combustion. A tired crank assembly shows up as vibration, noise and, in the end, engine failure.

Specifications

• Brand: ATHENA
• Manufacturer part number: S410130320001
• EAN code: 8052780270557
• Engine: 2-stroke

When to replace it?

• Play at the big end (vertical movement of the connecting rod at top dead centre).
• Unusual vibration, dull noise from the bottom end.
• Signs of overheating or seizure on the small-end bearing or the crank pin.

During a bottom end rebuild, or as soon as play appears at the big end. A complete crankshaft saves you having the original crank assembly pressed apart and realigned.

Fitting tips

1. Replace the crankshaft bearings and oil seals at the same time.
2. Before closing the crankcases, check the side play and the run-out. Run-out is the deviation you measure with a dial indicator at the end of the shaft while turning the crankshaft: it shows whether the two flywheels are perfectly aligned. The lower it is, the less the engine vibrates.
3. Close up the engine with a new complete engine gasket kit.
4. Check the gearbox bearings while the cases are split.
5. Tighten the flywheel nut and primary gear nut to the torque given by the manufacturer, then fill up with fresh oil.

Why ATHENA?

Founded in 1973 near Vicenza, Athena is an Italian engine gasket specialist that has made its gaskets on its own production lines since day one, as well as a renowned manufacturer of pistons and cylinder kits. The brand supplies original equipment to manufacturers such as KTM, Ducati, Fantic, Piaggio and Triumph, and is a partner of the MXGP motocross world championship.

Spare parts and items to plan

• Crankshaft bearings and seals : see the selection
• Complete engine gasket kit : ATHENA P400130850211 · ATHENA P400130850204
• 2-stroke oil : LIQUI MOLY 1 L · LIQUI MOLY 4 L
• Spark plug : NGK 3961 · NGK 5722

Frequently asked questions

Are the bearings supplied?
No: you'll need the crankshaft bearing and seal kit, the complete engine gasket kit, the gearbox bearings if required, engine oil and a new spark plug.

What does “run-out” mean?
It's the deviation in the crankshaft's rotation, measured with a dial indicator at the end of the shaft. Very low run-out means the flywheels are perfectly aligned: the engine vibrates less and its bearings last longer. It has nothing to do with full-circle flywheels or balancing, which concern the shape and weight distribution of the flywheels.

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