I adjusted the valves a couple of times on a 2006 yz450f. Being that they were needing more frequent adjustment I decided to send the head out and have all new stainless valves installed. (New seats, springs, retainers and valves) When I received my head back I proceeded to set the initial valve clearances and ended up needing 1.35mm shims on all 3 intake valves and 1.65mm shims for both exhaust valves. My assumption is that the seats were not actually replaced resulting in the need for such thin shims. Should I bother trying to have something done or just go with it?