The two large holes in the main web feed the crank and direct oil to the cam bearings. DMR makes these aluminum restrictors that, once hammered into place with red Loctite, reduce oil volume to the cam bearings, which forces more to the main bearings. In this photo, the restrictor is not installed deep enough. Left in this position, it will restrict the oil passage to the mains and not to the cam. Be sure to drive the restrictor in past the main oil passage intersection.