Ever since I did my big bore, about 4,000 miles ago by now, I have been running straight Castrol 10-40 dino oil ($8 a gallon too). It seems to run just fine and is pretty quiet mechanically to boot. Hmm. This is with a big bore, new clutch springs and belt drive since then. No problemo.
All this talk about how synt is required I can say without a doubt is pretty much manufacturer BS. I know that the synthetic has better friction magic and all, but as far as it being required, I seriously doubt that. Action speaks volumes eeh? (that's for wojo, eeh?)
I will be trying the new Vavoline that Gary James spoke of as soon as my bike comes home from the GF's house. I have her Magna getting it all finished up so she can ride. I even put my last 4 quarts of Amsoil in her bike as a test. Mine is sitting in her garage (keys are with me though) starting to get the shakes too as it's been 80º+ the last few days, but then again, my butt doesn't mind a few days off after the long haul to Ga and back.
So, when I try the Vavoline new mc oil, I'll report back.
