ATHENA Cylinder Head O-Ring Ø107.7x1.78 mm for GAS GAS EC 250, MX 250, MX 300 and SUZUKI RM 250 1996-2014

On GAS GAS EC 250, MX 250, MX 300 and SUZUKI RM 250 from 1996 to 2014, the ATHENA Ø107.7x1.78 mm (culasse) M751802425004 O-ring fits in place of the original part. Sold by size, this O-ring replaces one that is flattened, hardened or cut, provided you match its inner diameter and cross-section exactly. An O-ring doesn't take well to being reused: once squeezed into its groove, it has taken on the groove's shape and can no longer be trusted to seal.

Specifications

• Brand: ATHENA
• Manufacturer part number: M751802425004
• EAN code: 8051757115792
• Material: NBR (nitrile rubber)
• Hardness: 70 Shore A
• Engine: 2-stroke

When to replace it?

• Oil, coolant or fuel weeping at a plug, cover or fitting.
• O-ring flattened, hardened, split or pinched when you take it out.
• O-ring swollen or softened after contact with a fluid it isn't suited to.

Change the O-ring every time you remove the part it seals: it costs a few cents, next to the price of a leak. Measure the inner diameter and cross-section thickness of the old ring with a caliper, without squashing it, or use the size given in the workshop manual.

Fitting tips

1. Clean the groove and the mating surface: a grain of sand or a scrap of old seal is enough to cause a leak.
2. Lightly oil the new O-ring, or coat it with a compatible grease, so it seats without twisting.
3. Lay it in the bottom of its groove without rolling it or stretching it more than necessary, then bring the parts together squarely.
4. Tighten to the torque in the manual: an O-ring seals through controlled compression, not maximum tightening.

Why ATHENA?

Founded in 1973 near Vicenza, Athena is an Italian engine gasket specialist that has made its gaskets on its own production lines since day one, as well as a renowned manufacturer of pistons and cylinder kits. The brand supplies original equipment to manufacturers such as KTM, Ducati, Fantic, Piaggio and Triumph, and is a partner of the MXGP motocross world championship.

Spare parts and items to plan

• Grease : MOTUL 400 g

Frequently asked questions

How do I measure an O-ring?
Two dimensions are enough: the inner diameter and the cross-section thickness (the diameter of the rubber “cord”). Measure without squashing the ring, or take the dimensions of the groove.

Can I reuse an O-ring?
It's not recommended: squeezed into its groove, it has taken on its shape and hardened. At this price, always fit a new one.

Which material?
NBR handles oil and fuel; FKM (Viton) stands up better to heat. The material is listed in the specifications when it is known.

Compatibility

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

Fits:
GAS GAS EC 250 2014
GAS GAS EC 250 2013
GAS GAS EC 250 2012
GAS GAS EC 250 2011
GAS GAS EC 250 2010
GAS GAS EC 250 2009
GAS GAS EC 250 2008
GAS GAS EC 250 2007
GAS GAS EC 250 2006
GAS GAS EC 250 2005
GAS GAS EC 250 2004
GAS GAS EC 250 2003
GAS GAS EC 250 2002
GAS GAS EC 250 2001
GAS GAS EC 250 2000
GAS GAS EC 250 1999
GAS GAS EC 250 1998
GAS GAS EC 250 1997
GAS GAS MX 250 2013
GAS GAS MX 250 2012
GAS GAS MX 250 2011
GAS GAS MX 250 2007
GAS GAS MX 250 2006
GAS GAS MX 250 2005
GAS GAS MX 250 2004
GAS GAS MX 250 2003
GAS GAS MX 250 2002
GAS GAS MX 250 2001
GAS GAS MX 300 2013
GAS GAS MX 300 2012
GAS GAS MX 300 2011
GAS GAS MX 300 2010
GAS GAS MX 300 2009
GAS GAS MX 300 2008
GAS GAS MX 300 2007
GAS GAS MX 300 2006
GAS GAS MX 300 2005
GAS GAS MX 300 2004
GAS GAS MX 300 2003
GAS GAS MX 300 2002
GAS GAS MX 300 2001
GAS GAS MX 300 2000
GAS GAS MX 300 1999
GAS GAS MX 300 1998
GAS GAS MX 300 1997
SUZUKI RM 250 2000
SUZUKI RM 250 1999
SUZUKI RM 250 1998
SUZUKI RM 250 1997
SUZUKI RM 250 1996