ATHENA Piston Ring Set Ø56 mm for KTM SX 150 2009-2025

The ATHENA S41316219 set of piston rings (Ø 56 mm) is designed for KTM SX 150 from 2009 to 2025. Piston rings sit in the grooves of the piston. They seal between the piston and the cylinder, carry heat from the piston into the cylinder and, on a four-stroke, scrape oil off the cylinder walls. Once worn, they let compression leak past: the engine loses its punch.

Specifications

• Brand: ATHENA
• Manufacturer part number: S41316219
• EAN code: 8057018265121
• For ATHENA piston
• Diameter: 56 mm
• Engine: 2-stroke

When to replace it?

• Loss of compression and power, harder starting.
• Ring end gap, measured in the cylinder, larger than the figure in the manual.
• Ring stuck in its groove or showing traces of blow-by.

At every top end inspection, and at the latest when the piston is replaced. On a piston that is still within spec, new rings at mid-life bring the compression back. As a Cross-Mania guideline, the complete piston is replaced every 20 to 40 hours of engine running depending on whether you race or ride for fun.

Fitting tips

1. Clean the piston grooves (a broken old ring makes a good scraper) without widening them.
2. Place each ring in the cylinder, pushed in square with the piston, and measure its end gap with a feeler gauge.
3. Open the rings just enough to slip them over the piston, by hand or with ring pliers: opened too far, they distort or break.
4. Mark facing up, gap correctly located on the pin in its groove: a badly placed ring breaks on the first turn.
5. Lightly oil the cylinder and the rings before reassembly, with a new top end gasket kit.

Why ATHENA?

Athena, an Italian company founded in 1973 near Vicenza, designs gaskets, pistons and cylinder kits for motorcycles. An OEM supplier to KTM, Ducati, Fantic, Piaggio and Triumph and a partner of the MXGP world championship, it develops its parts on the test bench and on the track with racing teams.

Spare parts and items to plan

• Piston : PROX · WOSSNER
• Top-end gasket kit : ATHENA · TECNIUM
• Piston pin : VERTEX · WOSSNER
• Spark plug : NGK

Frequently asked questions

Which diameter should I choose?
The nominal diameter of your piston, given in the title. The rings go on a piston of the same bore size.

Does the engine need breaking in?
Yes: one hour of gentle break-in, without sustained full throttle, so the rings bed in to the cylinder.

Compatibility

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

Fits:
KTM SX 150 2025
KTM SX 150 2024
KTM SX 150 2023
KTM SX 150 2022
KTM SX 150 2021
KTM SX 150 2020
KTM SX 150 2019
KTM SX 150 2018
KTM SX 150 2017
KTM SX 150 2016
KTM SX 150 2015
KTM SX 150 2014
KTM SX 150 2013
KTM SX 150 2012
KTM SX 150 2011
KTM SX 150 2010
KTM SX 150 2009