Thats correct.. good oil retains its molecular bindings with time and does not break up. Additionally, oil that ranks higher ratings than the era of technology engine of bike belongs to is an over kill and waste of money. Among, other than american standards(SF, SG, SH, SL all pre 2005 engines and backwards compatible), the most important is the Japanese JASO MA/MA2 which specifically address bikes and especially those with wet clutch. Basically CG-125 is SF rated (pre 1988 era) and backwards compatible with SG/SH/SL. Therefore, an oil with ratings of SF, SG, SH, SL plus having JASO MA ratings will be the perfect oil. Only usage will show the consistency in smoothness over time and thus such an oil is perfect feed of subject engine if addition to its advertized standard ratings it provides consistency as well.