If you did not heat the case when closing it to allow the bearings to seat into them in a resistance free manner, you probably "side-loaded" the crank bearings. This can be the source of your resistance, and will make the bearings short lived. (That is, if you installed the bearings on the crank first. If you installed them in the case first, you would need to heat the bearings when closing the cases to expand the inner race and allow the crank to slide right into them....same problem) Just speculation.