I have a 2007 Goldwing that I purchased new, it has always had a ping under power, dealer says that there is nothing wrong with it. I have tried all different types of fuel, octane etc. tried shifting at higher RPM. The motor runs good and seems to have plenty of power. This happens mostley in 3, 4th and 5th gear even at 3000 RPM and up, open the throttle to much and it pings. I am using Amsoil full synthetic 10/40 and have from the time it was new, not that it should make difference. Any suggestions on what I could do.