Which oil?

[His Dudeness]

I haven't read into it, but....

Ah, the genius of the internet commentator  :rollin :rollin :rollin

If Mr Yamaha says SL or CF spec, and the oil says SL or CF spec on the bottle - then its up to the job, regardless of marketing gimmickry that sooo many people seem to fall for.

i'd say the more typical internet commentator response would be to quote a some technical jargon that you've read off wikipidea and dont properly understand and use it to justify an argument. if you want to save a few pound by skimping on oil then go ahead.