I have a 1999 Mule 550 which only had 25 psi on compression test. Leak down test indicated cylinder or rings issue, as I could clearly hear the air leaking when I removed the dip stick. Nothing out of the exhaust, & maybe a little out of the intake. I've removed the head, & there's a lot of carbon build up on the valves. I've ordered new valves, & am engine rebuilt kit, complete with piston & rings. When you pulled your piston, did you remove the engine, or were you able to remove the piston while the engine was in the frame? Thanks! I made the mistake of buying this sight unseen while I was deployed, & didn't think about asking for a compression test prior to paying.