The Castrol Power RS is API SL/JASO-MA2. The old Honda spec was API-SG.
JASO-MA2 – This specification was introduced in 2006 for modern motorcycle engines. As well as being a higher standard of oil the JASO-MA2 approval means the oil is suitable for use in bikes with catalytic converts in the exhaust system.
I have always run thick 30wt oil (GC) now I use the 0-40wt EDGE.
I think I will be fine since I only have about 20 Quarts to run thru and I was planning on a new Cat and better 02 sensor before my next smog check.