I broke my right valve guide two weeks ago and tore the quad down to the piston. Everything looked okay no major damage to the head and piston looked good besides carbon buildup. I was wondering about the installation of the valves. i ordered 4 new kibblewhite valves with guides. has anyone installed valves before? do i need to buy new shims or will the old ones work? any advice or help would be great! - thanks, Joe