well I would roll the cy up to TDC that I was checking and put some rope in the spark plug hole to keep the valve from falling. I say this because with air in there it is holding it tight and not let it fall down a little. so you can move it. you need to be able to slide is up and down and side to side to get a feel for it to see if it is to tight. I know this is not the corrected way to check them..but will give you some idea.I mean if you got push hard or pull hard to make it move you know it is to tight.