The 1.5 Qts of HONDA oil and HONDA OEM filter and proper new drain gasket cost me @ $25.
HONDA suggests that the oil and filter be changed every 8000 miles, or once each year.
My scoot has covered 2350 miles from (new) purchase 3 mos ago; getting thru the break-in period, this is its 4th oil & filter change. Riding through the cold winter months (0 > 35 degrees Fahrenheit), I probably will change the oil about every 600 miles, and go 1000 to 1500 in the summer for the duration of ownership.
I'm one of those old school guys when it comes to oil changes (but then I tend to keep my vehicles for a few 100 thousand miles)Fish
