Thespeed wobble you are talking about with the front bars,which ismost often caused a tank slapper. I have had numerous times, never on the HD though. The best thing you can do is lay on the throttle and lighten the front end up. Best to get it off the ground so you can get ahold of it. nothing I ever "want" to experience.

heres a vid from on the bike of what it would look like. http://www.youtube.com/watch?v=5AMvAsh_MRM

this is a vid of what it looks like off the bike http://www.youtube.com/watch?v=ymvVv_zbOjk

 

My brand new 1965 Electra Glide went into a wobble at 70 mph going down hill. It was so severe the tire was "chirping" as it went sideways to the straight line. Turned out to be some missing shims between the front forks and the wheel hub. Factory error.

My 1984 Honda Aspencade would go into a wobble anytime I let go of both handlebar grips. One hand on the bar and it would recover. Go figure!

This Ultra doesn't wobble, but at 100 mph the fairing seems to "hunt" a tiny bit. Could be wheel hop, don't know, don't go that fast anyway.[:'(]

 

That sounds like a tank slapper..which is more related to the front end.

But, with rubber mounted engines like the one on my touring model, the swing arm pivot is not anchored, so the rubber mounts can compress at speed and the swing arm can actually pivot which can cause rear wheel wobble...especially at higher speeds and on sweeping turns. I added a rear stabilizer bracket hit (Ride-Str8) and I can tell a difference in the handling both in mountain riding here and at speed on the interstate.

 

Happened once,I found the problem and fixed it.Now when it happens I know I'm going at least 100mph and that is because of the windshield.

 

Sounds to me like the best thing to do is ... don't go so frickin fast.

 

Check your tire pressure, maybe add a fork brace if possable.

 

Mine was due to a flat spot on the rear wheel. Happened via a pot hole. The spokes had lossened a bit. Check your spokes if you have laced wheels.

 

back when i had my CBR900RR, i was riding with a friend who was on a TL1000R. we swapped bikes for a few miles and i experience a tank slapper on his bike right around 90mph. he was behind me and saw the whole thing.

not only did i just about shlt my pants and wreck his bike- he was watching.

somehow- by the grace of god (but id rather think it was my skillz) i rode it out and recovered..... and promptly took my RR back

 

It happened to me years ago also on a Kawasaki 900.Don't remember any details but I know it was at fast pace.It'll make you pinch holes in the seat.

 

Ive gotten tank slapper as under 30 mph. It is not a speed think it is somethin to do with the right forces and loads on the wheel I guess.