I don't usually bother taking anything apart. If it feels good, I put it on a plane and run it. If it runs reliably on the ground, then I fly it. The only reason to take it apart is if you're either planning on replacing the bearings anyway, or you think the seller lied to you and you're planning on sending it back for a refund. For my money, taking an engine apart just introduces opportunities to screw something else up.

I've only ever purchased two new engines. An LA 46 I bought 6 years ago, and a DLE-55 in August. Everything in between was either E-Bay or RCU Auction. The list includes two TT Pro-46's, an OS-46 FX, a TT GP-61. and two Magnum 91 FSRs. Not a bad running engine in the lot.

Brad