Well there's something I learned. I never calculated in the rotating remainder of the rods and that's quite a bit. That's the discrepance I was looking for. The balance weights are bearing on the big-end journal and so act thru that
journal, the diameter of the weight has no significance. So long as it's round. But I can see a case for hanging the weights on a thread. I also see lots about "rocking couple." With the greater volume of the flywheel in the centre of the crank, only part of the
cheeks can contribute to a "rocking couple." I'll have to wear that. . I'll go and hide my head for a while in shame. The trouble is that there are balancers around, but they say "sure I can balance it, how do you want it done?" I'm better off doing it myself. The
crankshaft grinder , a brilliant bunch of blokes,( Crankshaft Rebuilders) balance cranks, but for big engines, they didn't want to know about an old pommy twin that's gonna vibrate your fillings out no matter what they do....Thanks everybody.....