Does it happen when slowing with no braking, or when braking? If just slowing with no braking, have neck bearings adjusted. If it shakes/shudders when braking, probably a warped rotor.

 

 

This is not even a little bit normal! Most likely the "Fall Away" (neck bearing)needs to be adjusted.

 

Some of these folks don't know a good running bike from a bad running weed eater, - but they have a lot of advice.
I see where they write on here "wobbles are OK at 70MPH !'
It is NORMAL !
omg, REALLY?
The bike will twitch through turns- Normal!
I just scream-
They remind me of people that have no mechanical aptitude driving around in a V8 , it is running on 5 cylinders, and they don't even know it.
I would not ride a bike that twitched.
I would, however, fix the dam thing.-, and stop calling "normal"

 

Over the past twenty years I've adjusted head bearings on most of the motorcycles I've owned.

One case: a year 2000 Kawasaki Voyager that would wobble in fast sweepers no matter what I did. It would also wobble while slowing as I passed thru around 35 mph if I took my hands off the bars. Most other Voyager riders had the exact same problem, but most of them had decided this was due to an overly-flexible frame.

I decided to play with the torque on the head bearings. After a few guesses and test rides, I found a sweet spot of torque that stopped the high speed wobble in sweepers, prevented a straight-line weave, but did allow the bike to wobble as I slowed down thru 35 mph with hands off the bars. The key words are the bold ones. A rider should never take hands off the bars as they slow down.

A properly adjusted steering head will prevent weave at straight-line cruise. It will prevent wobble in high speed sweepers. But when adjusted to this sweet spot, it will also allow a wobble to develop if the rider takes his hands off the bars while slowing down as the bike passes through around 35 mph.

My most recent experience, my 2018 RGU. It had a too-tight steering at delivery. The bike would weave in straight-line cruise. It would not wobble in high speed sweepers, or when slowing down through 35 mph with hands off the bars. I knew that this most likely meant the head was a hair too tight, and in fact, the head FELT too tight. With the bike off the ground, the front wheel would not swing easily from side to side. I knew, it was too tight.

So I adjusted it, according to the book. I set the torque according to the balance described above. The bike is now perfect in every respect. It doesn't weave at straight line speed. It doesn't wobble in high speed sweepers. BUT, if I take my hands off the bars while slowing down through 35 mph, it will wobble.

What I want in my bike is that it never weave, and never wobble, and never wobble while slowing down, as long as I keep my hands on the bars while I slow down. I do like to ride with hands off the bars while at speed. My bike doesn't wobble at speed with hands off the bars. It will only wobble while slowing down, and only if I take my hands off the bars.

The obvious solution, then, is what I've been told by many riders, and experienced myself with dozens of motorcycles: Keep hands on bars while slowing down. In all other conditions, taking hands off bars is fine and safe. But not while slowing down. Seems simple.

 

This happened to me today and freaked me out a little. I normally have my hands on the bars when slowing but this time I was trying to zip up the sleeves of my jacket when going through my neighborhood. I was going around 30 mph and decelerating and BAM, the bars started to wobble. Just grabbing with little to no force stopped it immediately. Years ago on my 2014 SG I got that wobble if I had cruise on and was going 40-50 mph which was caused by the neck bearing. This is a totally different issue as its at a slower speed while decelerating. I just check pressure so that was up to spec, with less than 2500 miles on the new bike I would hope it's not the neck bearings but definitely has different circumstances. At speed and in corners it's solid as a rock.

 

LOL - no company is responsible for what happens when your hands are not on the bars.

Once you eliminate tire pressure, alignment, head bearing, it comes down to the geometry of the bike, and its not designed to be stable without hands on the bars.

 

My Yamaha VStar 1300 Tourer did the decel wobble at 35ish mph. I rarely, rarely take my hands off the bars, but did accidentally discover that. 3 separate bike mechanics examined (all 3 reputable) it and said there were no issues and that it was normal for many bikes. It’s also dependent upon the actual tires, the pressure, weight on the bike and the actual road you are on, according to all 3.

They did of of course say, accelerating, at higher speeds and all other conditions it should never happen. I was also told that if the slightest touch of the bars did not steady it to bring it in. They also said most people never it that because that meant They took hands off the bars while decelerating. Bad move.

Haven’t even thought about it with my RGU. Maybe I’ll check.

***Disclaimer: keep at least one hand on the wheel****. Always.

 

My first 17 SGS had a wobble on decal about 35 mph, essentially straight from the showroom floor. I did not have my hands off the handle bars. I went to dealer and mechanic said the neck bearing needed tightened. I thought he was full of it but sure enough he tightened them and the wobble disappeared.

 

The problem is that if you tighten the steering head to the point that decel wobble is totally eliminated, then your steering is so tight that you almost surely will weave at cruise speeds 70 mph and thereabouts. Maintaining a straight trajectory will be a constant fight with the chassis, because the steering is slow to respond to road irregularities.

The price for this higher speed stability is a steering head loose enough that it will permit occasional wobble at slow speeds If And Only If rider’s hands are off the handlebars.

I suppose if if all you ever do is slow down, and you simply MUST take your hands off the grips while doing this, then it may not matter how the bike acts at 70 mph.

This is is a Motorcycle thing. All motorcycles are like this. Not just Harleys but all the other makes as well. Maybe some oddball front-end design are less prone, but the vast majority of motorcycles are of the conventional design, and all of them share this characteristic.