When I first got my engine back from the builder, he gave me specific instructions on break in. I ran the bike at 2000 rpm for two minutes (with a box fan in front) and shut it off for four minutes. I kept repeating the process until the engine was warmed up. The next day I re-torqued the head and repeated the warm up process. It took four head retorques before everything stayed tight. At 1500 miles, the head gasket started leaking. What I was never told about was the "Follow-up" torque checks. I annealed the old head gasket and gave it a light spray of Permatex Copper. I went through the same initial torque process and it took four cycles to get everything tight (again). After that I checked the torque again at 25, 125, 250, 500 and 1000 miles. They were tight at 1000, but the earlier four checks, there were still loose bolts (usually in the inner section). I've checked the torque at 2000 and 3000 miles and everything has been good. I don't know if they are supposed to require this much "Baby-sitting", but that's the route I ended up taking.