Piston and O-ring terms?

[Techno]

What is done when this pinning problem is fixed. This will probably answer the next question of what is it?

Whats meant by this pinning of the pistons? Is it the little pin for the rings?
Are the connecting rod pins a press fit, do they use those circlips and what do you think of those clips?


Are the head O-rings rubber or the squeezable metal gasketing rings?

[Riverman]

The fix you refer to, as I understand it is to burn out the existing pins from the side of the ring land using the EDM process, then drilling for the pin down through the piston crown. The pin is then pressed in and the hole in the piston crown is welded up.

The pin is used to keep the ring from rotating on the piston. This is to stop the end of the ring from springing out into the port (ouch).

I think all 2 stroke engines have pinned rings.

No idea about the head gaskets.

[Jay Smith]

Riverman is dead on on the piston ring locator question.

Most all OEM "O" rings for heads are viton material or in other words rubber like !