I run 100% synthetic(Redline oil) in my motorcycle, a 1992 Honda CBR600F2 with 56,000 miles. Went to synthetic after 5,000 miles. Motorcycles are much harder on oil as the engine oil is shared with the transmission. My bike redlines at 14,000 rpm, peak power is at 10,000 rpm, and I take it to redline almost everytime I accelerate - 0-60mph in 3.4 seconds. This bike is able to keep up with liter-class bikes only by shifting frequently to keep engine running in power band (8K-11K rpm). Warranty recommended changing oil every 8,000 miles, I changed it every 4,000 until it had 48,000 miles on it. Now, I'm going to change it every 8,000, let's see how it holds up. I know a guy who has 2 motorcycles (sportbikes), both with over 100K miles. He runs Mobil 1 only and changes oil, GET THIS, every 12,500 miles. He rides hard and his bikes run very well.