hello ..my '22 Honda Navi with @ 2800 miles & 1 year ownership is soon out of warranty about the time my riding season begins in March-April; so far I have stuck with semisynthetic 10w-30 for both engine & rear differential which met specs; now I will have 'options' to choosr different fluids...perhaps 10w-40 oil for the engine & 80w-90 gear oil for the rear differential to beef up protection; if you were in ssme situation what would you do? thanks...