I have a 2001 yz426f with approximately 300 hrs on it. I regularly check the valve clearance and two months ago the clearance dropped to .001 on all the intake valves. I shimmed the valves back to spec and put about 25 hrs on the bike before checking the clearance again. I checked the clearance last night and all the intake valves are back to .001-.002 . I know, I need new valves, now the questions. Can you replace the valves without re-cutting the valve seats? What type of valves do you recommend, OEM or aftermarket. I was contemplating sending the head to Eric Gorr for a complete rebuild but, I plan on selling the bike this spring and hate to put a lot of money into it. This bike has been bullet-proof and I plan on buying a 2006 yz450f this spring. I appreciate any recommendations.