There was a very long discussion on this about a year or so ago. Some heated discussion from what I remember with a ton of facts being tossed around.All that aside....

I use 89 but have been forced into 87 a time or two. Ive also accidentally used 92....so...I stick with 89 as called out by my manual and have not really noticed a difference when running 87 or 92.

SOLD: 07 Black BA, 39mm FCRs, TPUSA stage 1 head, TPUSA 813 cams, TPUSA 10.8:1 pistons, TTP #3 igniter, Specialty Spares Long Cannons, Tsukayu Hard Bags. 82HP/55tq NEW: 19 Goldwing Tour DCT