This is my 2nd post on this site after joining today. Thanks for all the info on this subject. My cherry(stock) 05 FXST Softail Standard started doing this a few weeks ago at about 85 mph on I-26 in a slight curve. It'll also wobble or gyrate at 75 mph in a straight stretch. The back and forth handlebar movement was about a 6" oscillation. I've refered to this motion as a gyration from hell. Wobble is an understatement. In 40 years of riding nothing was never this intense, except the time I got forced out of the road into a ditch and hit a driveway doing 55 mph. What worked for me? Stay in the gas and off the brakes and let off lightly. It stopped at gyrating 65 mph. At 20,000 + plus miles this was a big surprise. I am going to check all pivot points, steering head, and rear tire alignment as I recently had HD Michelin Comanders installed. Intelligence is not knowing everything, but knowing where to find the answer. Pucker factor was 8.5 as I made it out high and dry. I've been to a windmill greasin, seen a duck bred by a rooster, seen a weld bead fall off a piece of steel, but never heard of this before! thanks for all the help.

 

Check your spokes as well. I have an '04 and had it to 100mph briefly and not a hint of wobble. Last time I encountered it was on a '79 Yamaha 750 Special.

 

There must be something else going on, this has normally been associated with pre-09 touring bikes, Softails have a completely different suspension system.

 

Thanks for this post! I had also asked around and sure enough, it's the rear spokes. After checking for play, and loose nuts, and bolts, I put my knee against the rear fender and looked for movement. I could see about 1/2" play in the tire and no movement near the axle. I checked the spokes and that's the problem. They are very loose. I'm surprised the HD tech didn't find this when they installed my new tires a while back(a few hundred miles back, last Fall). Now comes the fun part.

 

Thanks, I found the problem. So, what do pre '09 touring bikes and softails have in common? Spokes. My rear spokes are very loose, and that's the problem. Now I'm looking for a 16" x 150/80 solid rear wheel. I'm speculating the wobble shows up more with touring bikes with laced spoke wheels because they are much heavier than most softails.

 

Not saying the problem doesn't exist, but none of the touring bikes I've owned wobbled. This might be because I ride the bikes within their limits.

The death wobble reminds me of BMW's problem with final drive failure. Owners complained. Next thing you know it's on the news, lawsuits are filed, the NHTSA opened an investigation, folks are shying away from the marque, etc.

 

Never happened on my '08 glide but then I maintain it properly rather than applying bandaid.