For no particular reason I picked up a free rental compression tester at AutoZone while I was there for some other stuff on Thursday. Pulled plugs, put the tester on top, gave it a spin. EIGHTY! middle SEVENTY-FIVE! bottom SEVENTY-SEVEN After 48 anxious hours I tested it again with a different gauge at the Yamaha dealer and found 118T-110M-118B Lesson Learned: Don't trust free diagnostic test equipment from a place that only sells parts.