What type main bearings do yammis have, C3 or C4 clearance? This is not specified on the OEM bearing. Single one costs as much as all the bearings in the engine combined including 2 main ones, if bought in specialized shop, all in C3 clearance. Not sure about main bearings though, C4 are a bit hard to come by, even in standard sizes. Also what makes bearing outer ring and housing surface go like this? housing1 housing2 bearing Prolongued axial fatigue?? Bike was running completely normal before disassembled. Had other issues.