I took my 2007 Goldwing to the dealer to have an oil change done and was told that my clutch plates are wearing. The two mechanics could tell from the smell. I only have 18,000 miles on my bike. The mechanic suspects it comes from my choice of oil. I use 10 - 30 Amsoil full synthetic. He recommends using regular petroleum based Honda motorcycle oil. He said the full synthetic oil also weakens the engine seals. He recommended that I stay with the full synthetic until the clutch plates eventually require replacing. He said that the plates have already soaked up synthetic oil, so I should stay with synthetic until the plates are eventually replaced. I would appreciate other opinions. The mechanic seemed very sincere, but thought regular petroleum based motorcycle oil is better for the GW. I wish I could minimize the damage that is being done to my clutch plates. Any recommendations or ideas would be appreciated. Thanks.