Resurrecting an old thread.... No flames needed guys and gals. At least there is an answer from Kendall R&D posted in another board I visit....
I've sent an email to ConocoPhillips asking them which Kendall GT-1 20W50 oil they recommend using in a Gold Wing. Will post what they say.
Here is the response from Kendall R&D:
"Either product will provide the protection that your motorcycle requires. I would recommend whichever is easier to find locally.
The Kendall GT-1 Motorcycle 20W-50 meets the API SN engine protection and JASO MA1 friction requirements.
Kendall GT-1 High Performance 20W-50 has higher levels of ZddP and contains our Liquid Titanium(R) Protection additive. It also meets API SN and has JASO friction MA.
Your bike would have called for JASO MA friction (this is a test of both static and kinetic friction characteristics of an oil, to protect the wet clutch). A couple of years ago, JASO split the friction specification, so MA1 is the higher friction half of the specification and MA2 is the lower half, and MA is still the entire acceptable range. So, either MA1 or MA2 would meet the MA requirements. High Performance 20W-50 is almost exactly in the middle of the spec, with one measurement just above the mid line and one just below. Thus it is a MA, because both results must be above the midline to be MA1 and both must be below the midline to be MA2. I hope that makes sense."