Join Date: Aug 2012
Location: tri-state area, Michigan, USA
Model: 1986 GL1200I
This is just like any other OIL THREAD. With the heat generated by a motorcycle engine (and a GoldWing engine) and the oil being used for the transmission and the clutch, I don't see any advantage to using synthetic oil. Oil should be changed often in "motorcycles" and GoldWings. I'm sure that this is the very same reasoning that your Honda techs used.
I use what my engine, transmission and clutch were developed and tested with, Castrol GTX 10W40!!
Send lawyers, guns and money
"I feel thin, sort of stretched, like butter scraped over too much bread" Bilbo Baggins
1986 GL 1200 Interstate, Poorboy Conversion,Pinstriped by Charlie Buzzard
1975 GL 1000, Fermenting
Plus, 2 garages and one shed full