Motorcycle Repair: Motorcycle Wobble, rear wheel bearings, softtail

Question
I have a 1993 custom softtail; at around 65-75 mph the bike starts to wobble. Sometime when I get up to 80 mph it will stop the wobble and other times it gets worse and I have to back off. It's to the point where I cannot ride on the highway comfortably. This is not a new problem, I'm doing more highway riding and can feel it more. It's not a vibration like a wheel being out of balance, it's a wobble.
I have replaced both the neck cups and bearing and it didn't help, I also changed my front wheel. I changed from the stock 21” wheel to a new stock HD 16” front wheel but that didn't help either. I'm looking for suggestions what to look at next.
                                                             Thanks
                                                                  Tony


Answer
There are several things that can cause a wobble. You have replaced the neck cups and the front wheel so that elimates those. You need to check your rear wheel bearings and your swinging arm bearings. Both can cause the problem.
Good luck and happy riding
Mike