I use Shell Rotella T full synthetic in the blue gallon container. I get it at Walmart for about $13.00 a gallon. I have used it in several bikes in the last few years and have not only had no problems but it seems to run smoother, it's more quiet, and it shifts easier. It is also one of the true full synthetic's. It's actually a heavy duty truck oil, but what the hell it works fine for me.