ATHENA Forged Piston for KTM EXC 250, GS 250, SX 250 1995

ATHENA offers this piston kit for KTM EXC 250, GS 250, SX 250 1995. 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 EXC 250?

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 20 h in hard use and every 40 h for leisure.

Specifications and fitting tips

• Engine: 2-stroke
• Size : 68 mm
• Manufacturer part number: S4F068000050

Spare parts and items to plan

• Piston rings : VERTEX · WOSSNER
• Piston pin : WOSSNER WP033 · WOSSNER CW18
• Piston pin clips : WISECO · VERTEX
• Top-end gasket kit : ATHENA · VHM
• Small end needle bearing : PROX · WOSSNER
• Spark plug : NGK 6664 · NGK 3520
• Coolant : LIQUI MOLY 1 L · TWIN AIR
• 2-stroke oil : LIQUI MOLY 1 L · MOTUL 1 L

Compatibility

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

Fits:
KTM EXC 250 1995
KTM GS 250 1995
KTM SX 250 1995