Just picked up a super clean, very low hour '07 YZ450 that has a cracked case. Low hours like under 50. I have a fellow TT member breaking down a bottom end right now to sell me the cases and what I am wondering is what should I replace while I am in there? I know clutch is good and valves are still in spec, piston has to be good with the amount of hours. Do I need to replace piston rings because it was torn down? I know I will need a full gasket set but is there anything else? I have the abillity and tools to complete the job just looking for some helpful insight on what I need to check out or look for while it's torn down. Thanks for any responses and tips.