Its best to attach a flywheel to the engine and tighten it down. heat up the case a little and place a fairly large zip tie thru the exhaust opening. Then turn the flywheel and force the piston up on the zip tie, it is ok to use pliers on the flywheel. Once the sleeve is popped up slightly i like to spray a little wd-40 onto the sleeve and slowly and very very carefully pry it out with a screwdriver, be sure to work your way around the sleeve and remember to be careful, once you can get your fingers around the sleeve grab it with a shop towl and pull it out.