As old as the Pilot's ignition system is (now 20 years and who knows where they got the parts - may be 30 years old by now...), a regular old NGK BR8ES or BR8EV will work just fine.
Off of NGK's web site,
here's a list of the different "types" of plugs they offer.
The
FAQ section covers most questions. (I learned stuff!)
PDF File of what the different numbers and letters mean.
The reason you need an "R" type plug - it's needed in your Pilot, btw...
Heat Range reasons - and w/NGK, the lower the number the 'hotter' the plug.
In a Pilot, an 8 or 9 series always worked best for me.
Heck I used BR8ES or BR8EV's in EVERY two stroke powered vehicle I owned - bikes, jet skis, Pilots, sled engines...
Pretty much the catch all/do all plug.
Lean out your mixture to 40:1 w/the Yamalube. It's great stuff - used it for years in all my two stroke until I got out of the two smoke world and joined the valved side of life.