Bike's giving me a great deal pleasure but I am at that tenuous "rebuilt engine" stage of the project, consequently I am all over the old girl after every run. I have noticed what appears to be a leak around each plug. I thought this oil was coming from the cam seals so I replaced them both but the situation persists. The plugs seat, screw and tighten down OK but they do exhibit a bit of a "wobble" during the installation process. I know they should not be overtightened so I fear I may have to rethread the plug holes using either Helicoils or the Time Sert kit. Which do you recommend?