EC250 cracked cylinder head

Mostin3

New member
Hello, i'm new to the forum and a new GasGas owner.

I bought a 2014 EC250 a few months ago and have been out on it a few times without issue and love the bike. i went out last weekend and after washing the bike on arriving home, i noticed coolant weeping from the T piece that bolts to the cylinder head. I removed the T piece, saw the gasket was breached, fitted a new gasket and thought nothing else of it.

On Saturday, I went to an enduro practice track. bike was running fine, until about lap 8 when all of a sudden, i powered out of a corner and the bike stopped, followed by a cloud of steam coming from the motor. I looked down and noticed a large crack in the cylinder head, running across the top of it.

When i got home, i removed the top end to inspect the damage, fearing the worst. Evrything appears perfect, piston in fine, ring end gap fine, small end bearing fine, big end bearing fine, water pump impeller fine, PV fine, radiators are not blocked and are clean, as are engine coolant ways.

Mt gut feeling is that the head casting is sub par and the coolant jackets have fatigued, either by poor casting or using neat water in coolant system and coolant has leaked into the combustion chamber, turned to steam and blown the head off.

I've ordered all new parts, as well as a piston, rings and the associated bearings and seals and will fit them next weekend. I am interested to hear other peoples thoughts on this and/or whether its a common issue?

Thanks in advance
 
2014 was 1st year to a new cast for the head. A few reports of them failing or being porus. Not sure if they addressed it for 15 and 17 models. Check parts fiche.
 
Happened to my 2014 300, I went for an S3 head.
There was some odd defects around the crack in the casting on mine.
 
I think i've managed to find out whats caused the cylinder head to crack. I put the head on an angle plate which has shown its warped. I am pretty certain in saying that the cylinder head bolts haven't been torqued correctly when the previous owner rebuilt the top end and its caused the head to distort when warm and then breaking the seal in the coolant ways allowing coolant to enter the cylinder.

Once my new parts arrive, ill be certain to torque everything exactly as per the book.
 
2014 was 1st year to a new cast for the head. A few reports of them failing or being porus. Not sure if they addressed it for 15 and 17 models. Check parts fiche.

Checked the parts fiche and the heads are the same from 2014 up to the new 2018.
 
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