Previously I had been using Amsoil 0w40 full synthetic in my bike. However after swamping my WR pretty bad this summer I've increased to changing my oil after every ride to make sure I've gotten all the crap out of the engine. So I'm switching to Shell Rotella as it is much more economical. Can someone explain why my mechanic told me not to use Synthetic Rotella T6 as it is not designed for the wet clutches, rather I should be using the Rotella T non synthetic. Thanks because he doesn't know it is JASO-MA.