Got a mate that rides an 07 YZ450F. Regular oil changes, synthetic oil, valves appear to be in spec. When the engine gets warm, there is a slight ringing sound as the bike is revved. I'd say the performance of the bike doesn't decrease, just that the ringing increases. Any ideas of why?
Also, I want to put a high compression piston in my YZ250F. I was told that I need to run race fuel to do this. However, the 08 Yz250F already comes with a high compression piston but does not require race fuel. Do I really need race fuel if I install a high compression piston on my bike? Thanks for any feedback given. DRN rules.
Also, I want to put a high compression piston in my YZ250F. I was told that I need to run race fuel to do this. However, the 08 Yz250F already comes with a high compression piston but does not require race fuel. Do I really need race fuel if I install a high compression piston on my bike? Thanks for any feedback given. DRN rules.