ATHENA Exhaust Power Valve Part ref. S410485303011 for GAS GAS EC 125 2013-2015

The ATHENA S410485303011 exhaust power valve part is designed for GAS GAS EC 125 from 2013 to 2015. On a two-stroke motocross engine, the exhaust power valve changes the height of the exhaust port with the revs: low for mid-range torque, high for top-end power. Once it sticks or clogs up, it stops moving and the engine loses either its torque or its over-rev.

Specifications

• Brand: ATHENA
• Manufacturer part number: S410485303011
• EAN code: 8051757138159
• Weight: 80 g
• Engine: 2-stroke

When to replace it?

• Flat in the mid-range or running out of breath at high revs.
• Valve stuck with carbon, or slow to return to position.
• Excessive play, weak spring or marked parts on teardown.

Clean and check the power valve at every piston change, and replace worn parts as soon as they develop play or stop moving freely.

Fitting tips

1. Remove the power valve in the order given in the workshop manual and note the position of each part.
2. Decarbonise the valve housing in the cylinder before fitting the new parts.
3. Check that the valve slides freely over its full travel, with no tight spot, before closing up.
4. Adjust the valve (spring preload, stop) as set out in the manual, then reassemble with new gaskets.

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

• ATHENA cylinder kit : ATHENA
• Piston : ATHENA S4C05400016A · ATHENA S4C04450001 · ATHENA S4C05400016B
• Piston rings : ATHENA
• Top end gasket kit : ATHENA P400485160003 · ATHENA P400485999003
• Cylinder head and dome : ATHENA

Frequently asked questions

Do I need to replace the whole valve?
No: replace the worn parts (blades, spring, shaft, seals) and check the others. Compare with the photo and your workshop manual.

Will this part fit my cylinder?
Check the compatibility list and the product name: some parts are made for the original cylinder, others for an Athena cylinder kit.

Compatibility

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

Fits:
GAS GAS EC 125 2015
GAS GAS EC 125 2014
GAS GAS EC 125 2013