This question is in my thread, but figured I would toss it out to all to get some more responses. My r80 when cold has 80lbs compression in the left cylinder and will not immediately fire. My right cyl when cold is 115lbs The valves are in tune at last check and the tapping sounds fine when started. Today I tossed in some marvels mystery oil and let it sit a few hours. Blasted it out, tossed the plug in and she started fine. Well with a bunch of smoke I let it run a couple minutes to burn the oil out then did another test. Left cylinder went from 80 to 122, right cyl went from 115 to 125. Thoughts? I'm guess a stuck and rusty ring from winter condensation?