I was reading through the thread and saw this...I thought I would share my method.

Take the motor out of the ride and remove the pipe...grab the flywheel in your fingers and put the exhaust port up near your ear and turn the flywheel over ....as the compression builds up near top dead center if you hear a hissssssing sound coming out of the exhaust you have what is called "leak down"...a little is okay but a lot means it's on its way out...

usually a small short hiss will be audible at first but as the piston climbs up in the sleeve the hiss stops...that is good....if the hiss continues all the way through the compression stroke that is bad...

If you think it's wore out then pull the sleeve and check it for scratches...if you dont have any scratches you can send it off to CEO or OSRocket to get the sleeve "pinched" to get some more life from the motor....or buy a new p/s