I believe I read that Charles Navarro (LN Engineering) stated you can do a 50/50 mix of automotive and motorcycle oil, but a full fill of MC oil would likely destroy the catalytic converters.
Check out his oil topics at
www.lnengineering.com
BTW, I was at a PCA Tech clinic yesterday where Charles gave a talk about motor oils...always an interesting topic, as our host mentioned.
Dang, that Motul fill is expensive!