The gasgas tends to drag the clutch a bit unless it has "just the right stuff"....
Eric Kangas first turned us all on to amsoil 0w40... Still have two bottles in the garage...
Many in the u.s. are happy with shell rotella syn 5w40. I think this is the one Glenn (GMP) and eric now prefer...
I switched to it in my bike before it got passed on to roostafish. Less clutch drag, nice clutch engagement, and smooth shifting...
jeff