Well, I am still new to this bike (2001 Honda ST1100PY) but the guy I purchased it from had Rockingham Sports bike shop service the bike, they had put Belray EXP 15-50 oil in (semi synth), I found that as soon as my bike is up to full heat, the gears appeared a little sticky and it was a bugger to get it into neutral, so I asked my Honda dealership what oil should go in it. They said they only put the Genuine Honda HP4 10W-30 (Semi Synth) into the ST1100's as they are a performance engine (Racing bike??). I asked about the W rating being so low at 10, the service guy said it was perfect for Perth WA temps, plus he said that Honda just keep changing the numbers, but the oil is the same.
That made a lot of difference to me for sure, the sticky gears now come in before the bike is even at full heat, what a bonus that was. When I then followed up with the Honda shop, they suggested I get the bike in a strip the clutch (They would I guess).
The bike does sometimes slip into neutral OK even when it is hot, but more often than not, I get to sit at the traffic lights flicking the gearshift up, down, up, down, up,,, Oh you get the idea. ::)
I will be giving the Valvoline a go next change (I will not be waiting the 6 months either, it is a little tiresome needing to turn the engine off before I can get it into neutral each time).
So I can only confirm what I have not been happy with so far, sorry for the negativity.
(Except to say that the Belray EXP was far superior to the Honda HP4, though still sticky gears when hot)