ATHENA Racing Forged Piston for KTM SX 65, XC 65, HUSQVARNA TC 65 and GAS GAS MC 65 2009-2026

ATHENA offers this piston kit for KTM SX 65, XC 65, HUSQVARNA TC 65 and GAS GAS MC 65 2009-2026. 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 SX 65?

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: S4F04500001A (A), S4F04500001B (B), S4F04500001C (C)

Available in several sizes: choose the one that matches your cylinder (stamped size or measured bore). Diameters: A = 44.96 mm, B = 44.97 mm, C = 44.98 mm.

Spare parts and items to plan

• Piston rings : WOSSNER · PROX
• Piston pin clips : WISECO · VERTEX
• Top-end gasket kit : ATHENA · PROX
• Small end needle bearing : PROX · ATHENA
• Spark plug : NGK LR8B · NGK
• Coolant : LIQUI MOLY 1 L · TWIN AIR
• 2-stroke oil : LIQUI MOLY 1 L · MOTUL 800 1 L

Compatibility

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

Fits:
GAS GAS MC 65 2026
GAS GAS MC 65 2025
GAS GAS MC 65 2024
GAS GAS MC 65 2023
GAS GAS MC 65 2022
GAS GAS MC 65 2021
HUSQVARNA TC 65 2026
HUSQVARNA TC 65 2025
HUSQVARNA TC 65 2024
HUSQVARNA TC 65 2023
HUSQVARNA TC 65 2022
HUSQVARNA TC 65 2021
HUSQVARNA TC 65 2020
HUSQVARNA TC 65 2019
HUSQVARNA TC 65 2018
HUSQVARNA TC 65 2017
KTM SX 65 2026
KTM SX 65 2025
KTM SX 65 2024
KTM SX 65 2023
KTM SX 65 2022
KTM SX 65 2021
KTM SX 65 2020
KTM SX 65 2019
KTM SX 65 2018
KTM SX 65 2017
KTM SX 65 2016
KTM SX 65 2015
KTM SX 65 2014
KTM SX 65 2013
KTM SX 65 2012
KTM SX 65 2011
KTM SX 65 2010
KTM SX 65 2009
KTM XC 65 2014
KTM XC 65 2013
KTM XC 65 2012
KTM XC 65 2011
KTM XC 65 2010
KTM XC 65 2009