Dyna death wobble?
Outstanding HDF Member
Joined: Nov 2009
Posts: 2,666
Likes: 133
From: TEXAS
this is just not right.
op fall away test is important
It is in the manual. You have to raise front end off the ground, take off windshield/fairing, cables
you adjust the tension on the neck and that determines how easily the front end moves. Too loose and it feels wobbly, too tight and doesn't center itself.
I adjust mine whenever I get a new front tire or if the front end starts to feel slobby
windshields and fairing will have a big affect on this
I set mine within specs in the book but favoring the tight side
the adjust ment specs are a guideline and after years of doing it it is mostly about feel
there are a million things that can cause what you are saying
if the bike was mine I would check in this order:
Check and adjust fallawy
check motor mounts
check fork fluid levels
check rear shocks aren't leaking or damaged
rear wheel alignment
check tires and or wheels and wheel bearings
install true track or sputhe
bring hand position down closer to top tree
6th Gear
Joined: Sep 2018
Posts: 13
Likes: 1
From: Corona ca.
I took my Viking saddlebags off.
I made new mounts that pulled them in closer and also further back at the same time I got new tires.
Then the wobble got worse .
I thought it was the tires. Because I had the bags before.
I read somewhere the bags being to far back could cause it.
Also have a Tsport type fairing.
Anyway took the bags off tonight and seemed to stop the wobble at high speeds. Still got a little in a fast sweepertho. But very slight.
I made new mounts that pulled them in closer and also further back at the same time I got new tires.
Then the wobble got worse .
I thought it was the tires. Because I had the bags before.
I read somewhere the bags being to far back could cause it.
Also have a Tsport type fairing.
Anyway took the bags off tonight and seemed to stop the wobble at high speeds. Still got a little in a fast sweepertho. But very slight.
Outstanding HDF Member
Joined: Mar 2015
Posts: 2,840
Likes: 900
From: Philly Suburbs
I think he meant he made new mounts for his Viking bags, not the engine...
6th Gear
Joined: Sep 2018
Posts: 13
Likes: 1
From: Corona ca.
Ya.
I'm working graveyard and wrote that while waiting for my shift to start.
Anyone who's worked graveyard probly knows how that will affect your thinking and or speech.
So I see now how my post was confusing.
But ya. I had bags before.
While I was making new Bag mounts. I got new tires.
So when I rode it after I thought the new tires caused the wobble to get worse.
The mounts I made put the bags about 1-1/2 rearward and raised them about an inch.
In all the posts I've read. Only one mentioned the bags.
Mostly they say the fairing. Or spokes bearings . Motormounts. All of which I've addressed.
I was getting some wobble but it was way worse.
I can't believe how much difference a small adjustment made. Especially since it's closer to the bike and your think more streamlined.
I'm working graveyard and wrote that while waiting for my shift to start.
Anyone who's worked graveyard probly knows how that will affect your thinking and or speech.
So I see now how my post was confusing.
But ya. I had bags before.
While I was making new Bag mounts. I got new tires.
So when I rode it after I thought the new tires caused the wobble to get worse.
The mounts I made put the bags about 1-1/2 rearward and raised them about an inch.
In all the posts I've read. Only one mentioned the bags.
Mostly they say the fairing. Or spokes bearings . Motormounts. All of which I've addressed.
I was getting some wobble but it was way worse.
I can't believe how much difference a small adjustment made. Especially since it's closer to the bike and your think more streamlined.
Tourer
Joined: May 2012
Posts: 335
Likes: 89
From: Reno, NV
I would try removing the bags and fairing and see what happens. I'm not buying that those are the issue. They can affect the wobble in certain ways, but highly doubt they are the cause. Removing them will give you a more controlled experiment.
Have you checked swing arm bushings? What situation does this wobble happen? High speed sweepers about 80 mph?
You might have to break down and take it to a shop that specializes in motorcycle frames, suspensions, and alignments. Someone that can hook the bike up to a frame jig, check that it is straight, and do an entire alignment. Any shop that does this with Harleys is likely well aware of the "Dyna sway", and will know how to solve it. Call around and see what they say. Looks like there's a few down there in SoCal.
Have you checked swing arm bushings? What situation does this wobble happen? High speed sweepers about 80 mph?
You might have to break down and take it to a shop that specializes in motorcycle frames, suspensions, and alignments. Someone that can hook the bike up to a frame jig, check that it is straight, and do an entire alignment. Any shop that does this with Harleys is likely well aware of the "Dyna sway", and will know how to solve it. Call around and see what they say. Looks like there's a few down there in SoCal.
6th Gear
Joined: Sep 2018
Posts: 13
Likes: 1
From: Corona ca.
I changed the swingarm bearings. Tightened the steering head. Tuned the spokes and made sure they were balanced.
Have progressive 940 shocks and progressives mono tube fork kit.
I took the bags off and the wobble stopped.
I had the bags on before with very little issue .
When I moved them that s when the wobble got worse. At the same time I got new tires. Which is what I thought caused it to get worse.
Have progressive 940 shocks and progressives mono tube fork kit.
I took the bags off and the wobble stopped.
I had the bags on before with very little issue .
When I moved them that s when the wobble got worse. At the same time I got new tires. Which is what I thought caused it to get worse.
Road Warrior
Joined: Jun 2017
Posts: 1,705
Likes: 1,017
From: Lawrenceville Ga.
Da Err..a senior moment sorry 
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Seasoned HDF Member
Joined: Jan 2015
Posts: 16,023
Likes: 7,148
From: Sandy Eggo's North County
I have a 2016 FXDL. Twice now while entering a sweeping right hand, down hill turn on the freeway(80ish mph), I have experienced wobble/tank slapping type of movement in the bars. Thankfully, nothing has happened but this is of great concern. I feel it important to list the modifications to see from any of you to try and help narrow down the cause and seek a cure. I have 13" forbidden risers with Protapers, conleys t-sport fairing, super brace and finally progressive 13" shocks. Tire pressure is good. There is also slight wobble while approaching speeds of 90mph. Any insight is appreciated.
Wanna fix it? Return it back to stock and don't exceed 55 mph. Sorry, but it's true. If you wanna run "80ish" (which usually means 110ish, then get a bike designed for those speeds. Harley don't make one, anymore. Triumph might be something to look at though.
You took one the *best handling HD's* and screwed it all up by listening to people that wanted to make a buck off of you. Well, you did, and they did. Now look what you've got. A bike that may have dangerous handling characteristics if an emergency maneuver is needed at speed.
Again, return it to stock config. It'll be safer for you in the long run.
* best handling HD is as compared to the rest of them.
Road Captain
Joined: Jun 2007
Posts: 632
Likes: 86
I had bags on my previous FXDC and frequently ran it at very high XXX speeds. Rock solid, no wobbles. They were H-D hard bags.
Now, I only use a duffel if I travel on my '12 model.
I have modified its configuration way far from stock and have no issues. Good grief. What those mods got me was a bike that will run with my late model BMW's etc. Changing from stock is not necessarily a bad thing and you do not have to get a Triumph to run fast, lol. Good lord.
.
Now, I only use a duffel if I travel on my '12 model.
I have modified its configuration way far from stock and have no issues. Good grief. What those mods got me was a bike that will run with my late model BMW's etc. Changing from stock is not necessarily a bad thing and you do not have to get a Triumph to run fast, lol. Good lord.
.