Has anyone here had a bad experience with them?? I ran a set years ago in a 355 that I raced. They were 11:1 pop-ups with the 1/16 ring pack. I ran them for 4 years with no issues, then sold the motor to a guy who ran them for another few years...no issues. Lately I've been reading online, and hearing from other racers that KB pistons are JUNK!! What happened? Did they change the design, machining?? Anybody have any issues?