Topic: What are these O-rings?

[skarbakka]

Hi,

I was wondering anyone could tell me what these o-rings are to. If you can't tell from my picture, they are orange and green  This is from a full gasket rebuild kit for a 76 cb 550f. 

Also, if I need to take my top end apart again to check the valve guide seals (which I stupidly did not check and I think one is leaking, i.e. "wet" plug), do I need to purchase a new head gasket. or can I use reuse it?  I just got the engine back together and the bike has only been about 20 miles since replacing the old gasket.

Thanks

[mystic_1]

The big ones look like the big o-rings that go around the base of each cylinder sleeve.  I think it was Terry who recently mentioned that leaving those out could cause oil to infiltrate between the cylinder sleeve and the cylinder block.

Smaller ones could be lots of different things.  Got measurements in mm?  Compare to the parts fiche.

mystic_1

[fastbroshi]

  I'm in the same boat. I realized what the orange ones were, but I'm still not sure where the green ones go...  I just had my head rebuilt and I know he used all the rings he needed.  Maybe extras?  Comparing the smaller orange ones, I figured they go around the oil squirters for the cam on the outside edge of the block.  There was three in the packet, so I figured they put in one extra, just in case you happen to flip one down inside the block.  Not that it would ever happen. 
  Also, I'm of the mind those head gaskets are kinda like torque-to-yield fasteners; use it once and it's done.