I´m an Old Biker and a retired mechanic who´s been riding a long time now ! . I decided This winter to get an Antique bike and to restore it as a Custom but to stay kind of close to The Original model with my own rat bike touches like ; Tuned Drag Pipes, Zenith Panhead Carb , a single seat, fork gators, black spokes and My Own HD Decals ! I did all that and it looks great, I wanted this for a weekend bike to take to bike shows but I like to actually ride my bikes also and not to just look at them through a beer glass. So now I have this 76 XLH 1000 with 5,500 miles and everything is working good on the bike except that the engine shakes like hell at 40 to 50 mph and it has some vibration tremors at idles , vibrations that actually rattle and shake the front wheel and the forks ! , I can understand now why it was parked for 23 years before I got it ! . I like the bikes ride and performance in general and it´s fast enough for what I want it for and I wondered why no one seems to say much of anything about Iron head 1000 Crank Balancing Problems with their engines ? A Twin Cylinder Shaking Is something I can handle , I rode a 68 BSA 650 Twin, A Lightning hard tail when I was Young and I had a Hard Tail 73 750 TX Twin also so I am no stranger to engine vibrations , but what this Harley is doing is totally sick and is boarder line on psychotic ! , If I bought a new bike that shook that bad I would return it instantly and not take it back from the dealer until it was fixed ! . This bike at 40 to 50 mph feels like it´s gonna snap the front forks and goose neck off the bike , it almost bounces the front wheel!. I know I need to tear it down to see if someone has been in there before and messed with the pistons and crankshaft before I blame HD for making such an earth shaker!. I guess what I am wondering about is did some of these bike shake like that when they were new ?!.With the problems the new ones are having with cranks slipping and timing chains I have to ask ? I have a Honda Shadow also and it shakes some but it´s nothing like this bike.