ATHENA Racing Forged Piston ref. S4F10100003 for KTM LC4 620, LC4 640, SXC 625 1994-2009

ATHENA offers this piston kit for KTM LC4 620, LC4 640, SXC 625 1994-2009. The piston slides in the cylinder and takes the force of the air-fuel combustion, passing it to the connecting rod and crankshaft.

Why choose a forged piston?

Instead of simply being cast, a forged piston is hot-pressed under very high pressure and then machined: its metal is denser and free of air pockets.

• Stronger when hot: it copes better with high revs, overheating and detonation.
• Lighter for the same strength: less stress on the connecting rod and bearings.
• Good to know: depending on the alloy, it expands a little more and is fitted with more clearance; slight noise when cold is normal.
• Why does it cost more? Forging tools, full machining and surface treatments cost more than simple casting.

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 KTM LC4 620?

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 50 h in hard use and every 100 h for leisure.

Specifications and fitting tips

• Engine: 4-stroke
• Manufacturer part numbers: S4F10100003A (A), S4F10100003B (B), S4F10100003C (C)

Available in several sizes: choose the one that matches your cylinder (stamped size or measured bore). Diameters: A = 100.94 mm, B = 100.95 mm, C = 100.96 mm.

Spare parts and items to plan

• Piston rings : PROX · WISECO 650 L
• Piston pin : WOSSNER WP009-SP · WOSSNER CW22
• Top-end gasket kit : CENTAURO 731A625TP · CENTAURO P655453
• Spark plug : see the selection
• Coolant : LIQUI MOLY 1 L · TWIN AIR
• 4-stroke engine oil : MOTUL 10W50 · LIQUI MOLY 10W40 1 L

Compatibility

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

Fits:
KTM LC4 620 2009
KTM LC4 620 2008
KTM LC4 620 2007
KTM LC4 620 2006
KTM LC4 620 2005
KTM LC4 620 2004
KTM LC4 620 2003
KTM LC4 620 2002
KTM LC4 620 2001
KTM LC4 620 2000
KTM LC4 620 1999
KTM LC4 620 1998
KTM LC4 620 1997
KTM LC4 620 1996
KTM LC4 620 1995
KTM LC4 620 1994
KTM LC4 640 2009
KTM LC4 640 2008
KTM LC4 640 2007
KTM LC4 640 2006
KTM LC4 640 2005
KTM LC4 640 2004
KTM LC4 640 2003
KTM LC4 640 2002
KTM LC4 640 2001
KTM LC4 640 2000
KTM LC4 640 1999
KTM LC4 640 1998
KTM LC4 640 1997
KTM LC4 640 1996
KTM LC4 640 1995
KTM LC4 640 1994
KTM SXC 625 2009
KTM SXC 625 2008
KTM SXC 625 2007
KTM SXC 625 2006
KTM SXC 625 2005
KTM SXC 625 2004
KTM SXC 625 2003
KTM SXC 625 2002
KTM SXC 625 2001
KTM SXC 625 2000
KTM SXC 625 1999
KTM SXC 625 1998
KTM SXC 625 1997
KTM SXC 625 1996
KTM SXC 625 1995
KTM SXC 625 1994