Friday, February 1, 2008

Center Main Bearing Web

Left-hand case-half, facing the pulley end of the crankcase. The offset hole in the middle of the saddle is for the dowel pin that locates the bearing shell. The hole at the 4 o'clock position is the oil hole, which connects to the main oil gallery.

Quite often when the crankcase is opened up for larger jugs the larger spigot bore is cut with a tool having a sharp point. This creates a stress riser and often leads to cracks in this area, which may extend across the main oil gallery.

The second photo is of the right-hand case-half, looking TOWARD the pulley end. Notice the lack of an oil channel.

However, unless the case has received the HVX mods all of the oil to this side of the crankcase arrives there via the channel behind the bearing shell of the #2 cam bearing.