BHJ balancers are a press fit. I had to hone the bore on mine to get it on my forged CAT stroker crank with an installer tool I made from an A/C clutch installer bearing, washer, and a long grade 8 bolt. A stock balancer should slide on easily, but should have no play in the bore. I have a spare engine with a TA internal balancer on an RPM forged stroker crank, and it slips on nicely with no play. Make sure your balancer is not cracked. If you can slide it on and it does not rock, you should be OK. If it rocks, You may want to call Eagle.
My BHJ was a press fit on the stock crank and a slip fit on the Eagle. This told me that the Eagle was a little small and measurements confirmed this. It was small by .001 but knurling the inside of the BHJ made it a press fit again. Pressed it on and off 4 or 5 times to make sure this fixed it.
Good point though his factory hub could be part of the problem.
I thought all the Chinese crankshaft problems were gone, but it appears they are not. My CAT crank needed the flywheel register machined to allow the flywheel to fit flat, and the keyway had to be shimmed with shim stock. The RPM crank was perfect in every way.