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By IanD
#2300
I took my universal short megaphone off yesterday so i can pack it with moire silencing packing, and i took it off i noticed this sat in the bottom or the header pipe. It is some sort of compressed metal gasket, i can only assume it came from where the header sits in the cylinder head? But that said i cant find one listed on the part books online?
Image
Thanks
Ian

#25674
It's the exhaust valve seat, don't you see that? You can even see the chamfered edge inside the ring at the top. It's come loose from the top, been bent and oval, and then blown out through the exhaust port...... Haven't you noticed the loss of compression lately? Regards, Anders F. R.
By Frank
#25682
If the first you have noticed of this is when you have found the seat in the exhaust then could it have been some disaster that has happened to a previous owner and since been repaired? I can't see that you wouldn't have noticed something amiss with performance or noise. If this is a possibility it's perhaps worth checking further with compression tests, valve clearance check etc before you remove the head to have a look.
By IanD
#25683
now i'm new to 4 strokes, but it doesnt look like a valve seat to me, it looks like several very thin washers with some sort of gasket material in between, the chemfer in the photo is actually the return lip in the top'washer' which holds it all together. I'd have thought a valve seat was hardened and machined surfaces, this part is fairly soft and easy to bend.

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