Moinsen , I’ve been driving a Phillips engine oil for a long time such a “universal” 15W-40 and changing the 2× a year, however, I have the feeling that if the engine is very hot in summer, the oil (so after 5 months and about 1200km) is much thinner than before, which makes me worry. I researched a little and found that especially with high-turning motors (my Honda SS50 turns up to 10,000U/min) the polymers of multi-range oil decompose and so out of the 15W-40 a 15W-20 o which in the worst case becomes a 15W. I think that this can be especially with the engine also gear and clutch are lubricated and the polymers in the oil are taken there special speed. Is it then worth it for me to drive a one-area oil? Since there also only a popular sieve filter is also unalloyed? I found this here for the summer ( and in the winter again the 15W-40):https://www.amazon.de/…/ref=ox_sc_act_title_1?… Would that do the engine good? I thought a SA E50 lubricates even better, because the thicker the better lubrication and the planes have also flown SAE 80 or so. Thanks in advance for the answers.