stupid exhaust valve question

[aceofspades9963]

I pulled them to clean and forgot which side goes up , the side with the indentations or the flat side . can't seem to find a diagram online.

 

[ABMax24]

They will only go in one way, if it doesn't slide all the way into the cylinder its backwards.

 

[aceofspades9963]

Yep I'm an idiot maybe I should have tried it before posting , they are indeed keyed. It was they way I thought they were though. Thanks