My 6th gen VFR has manual cam chain tensioners. The rear one has been slighting seeping oil since I got her a couple months ago. I chose to back the bolt out and replace the o-ring using some leak sealant to hopefully prevent this further. After turning it back inward which I thought was the correct amount of turns, I started the bike to listen and set the final turns. The engine sounded like it was missing a bit and there seemed to be a lot of cam chain noise. I shut it down, removed the crankshaft access cover and proceeded to turn the crank by hand, not noticing anything but figured this would help a bit in fine-tuning the manual tensioner a bit before cranking again. I have a young friend who was present and when he started turning the crank (still by hand) it got to a point where it seemed locked. He forced it, not extreme but enough now where the crank feels locked in both directions. I have not checked to see if it's locked at TDC in both directions yet, but will tonight hopefully. I did pull the lower engine cover off to get a visual on the cam chains. When I rotate it backwards a bit, the rear cam chain slacks a bit (toward the front), but rotate forward and it tightens up ... I don't know if that's normal. Could the cam chain have jumped a tooth or two by this procedure? I don't notice anything broken. Maybe I didn't have the tensioner far enough in and there was too much slack before I started the engine? Would there be enough slack to have caused the chain to jump teeth? Not starting the bike until I get it sorted. May pull the valve covers tonight for further investigation. Anyone else experience this? Opinions matter; experience preferred.