Death Wobble at low speed (gl1200 sei)

[KenwoodFox]

Hello! This is my first post here, and I cant tell you how excited I am!

I just went down and picked up my dream bike today, a gl1200 and Im literally so happy, no joke ive been absolutly looking forward to this! Im having some problems though and it looks like stuff thats been here before, i wanted to check in with some of the community to get some more information before I do a front end teardown.

Im seeing something similar to, or exactly like this thead here: viewtopic.php?t=27972
and ill post a video too here:

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It seems to go into a absolutly heart stopping death wobble at about 12-20mph, but, it only does it if you accelerate gradually. My brother hopped on it, and the first time he tried he just gunned it past 30mph and there was no wobble, only when you accelerate more gently (say, at about the normal speed you would from a stop light) does it enter this wobble.

Take a look at the video to see what im talking about! Exact timestamp is 0:15

Im thinking of starting with tire pressure first, looks like the rear might be a touch soft, and also checking the front bearings, then exploring what i can do about the tripple tree

And for reference i daily a 1980 cb750, just finished a full engine rebuild on it in the summer and it works great now~

Thanks for reading all this, I'm super interested to hear the responses!

[Rambozo]

Sounds like you know what to do.
Tire condition, tire pressure, wheel bearings, steering bearings, forks, swing arm bushings, etc.

[Bike...and Dennis]

The rear tire can cause a decel wobble. Never noticed it under accel, but...

If the rear tire is underinflated, it could maybe cause an issue. If the tires are slightly worn and Metzler brand it will definitely cause an issue and worn Dunlops are just about as bad.

The wobble I saw there was in the rear of the bike though.

[KenwoodFox]

Its really a super violent wobble, Im hoping its just the rear~ Ill work on it tomorrow and let you know what I find! I'm just so scared of it throwing me off, its absolutely not normal to have that happen right? I feel like any bike should be able to maneuver at around that speed.

Thanks for the input so far! Im already so in love with the bike~

[KenwoodFox]

Not to bump my own thread but, reading around online, namely here: https://www.goldwingfacts.com/threads/f ... 291/page-3

I just wanna confirm, this is not normal, right? Like I'm so scared to ride it right now till I really find something definitive...

Tires were a touch low, rear was under by 10psi, front was under by about 4, had a friend step on the back and we tested for obvious wiggle in the steering and front forks but, nothing stood out, everything feels pretty solid, ill be taking the front wheel all apart though.

Let me know yeah~ This is my first goldwing, and I want to get used to it and ride it safely!

[Rambozo]

Definitely not normal. Some bikes have a slight decell wobble only if you take your hands off the bars. So like the old joke, the solution is don't take your hands off the bars.

[Bike...and Dennis]

It may be as simple as a bad/low tire or as complex as a bad wheel bearing, or missing a rear spacer. You won't know until you crawl under the bike and look.

[KenwoodFox]

Ok! Adding a little more air to the front and rear tires defiantly helped! It still wobbles quite a bit.. more than I think it should, especially when going around a corner.. but its no longer so extreme, I'm not going to drive the bike any further than my street yet but I think maybe if I tighten up a few more things I should be good to go! We defiantly took the kick out of that death wobble!

Here's a quick vid I caught of me riding it!

You can see a little wobble in this one too, especially when accelerating.

[joecoolsuncle]

dude, i would be all over those neck bearings and servicing the forks and all the other stuff that has been neglected. first fast sweeper and u gonna get dead.

[KenwoodFox]

You're right! I'm going to do basically a full frontend tear down, I did take the time to check swingarm bearings while I was under there and they feel super solid, but the front, is deffo all coming apart, ill service everything. Im so excited with this machine!

[Bike...and Dennis]

If adding air to the tires helped, that's further evidence it's in the rear wheel.

I give up!

[KenwoodFox]

Update on the death wobble: Its better! but..

it still feels.. uncomfortable in turns, especially nice low turns, its not really smooth, you can tell its wobbling but slower and less dangerous. The bike has a lot of resistance to actually turning, and a very high affinity for following the road, camber in the road really screws up how I ride, but I think that's just because its big and heavy and I'm not used to it yet! it tracks on paint and road repair cracks so I have to watch out for them a lot more than on my cb750. I think I'm on the right path!

i did a frontend teardown, checking over everything moving to the back, dad says that the rear bearings feel out by a few thou, I cant honestly feel it but I trust his judgment and so next course of action is to remove the rear wheel and do a bearing inspection! Always appreciate your advice and input!

PS: Ended up removing almost 11lb of chrome stuff so far! (some of the more cool-looking pieces went back on in the end~ not this one though:

)

[Rambozo]

A Blackwing fork brace can really help with low speed maneuvers.

[Rednaxs60]

Nice Bike, you'll enjoy it. No need for an aftermarket fork brace if you could find one. The fork brace on these are far better, reminds me of a 5 lb anchor weight - it's not going to twist. Would check the front fork springs when you rebuild change out the fork oil. A 36 year old bike, or car definitely needs the suspension looked at. New fork springs, go with a 1.2 kg/mm rate, these are heavier bikes, will make a difference - Sonic straight rate fork springs look good. Keeps the tire(s) firmly planted on the road. Max out the tire pressure, 40 PSI front/rear. New steering stem bearings is a good idea.

Good luck

[KenwoodFox]

https://www.goldwingfacts.com/threads/w ... st-1106359

Anecdotal but posting it here to keep everything neat, will order new fork springs and prolly fork bearings just to be safe and thorough!

[KenwoodFox]

Another clue, ive been dailying the bike with few problems but, tonight I finished rewiring the trunk and I reinstalled it.

Omg, instant death wobble, horrible, it really scares me when it just shakes out of your hands like that.

Im thinking of attending a local goldwing meet, maybe talk to some people, but the important takeaway is:
without trunk, no death wobble,
with trunk, death wobble

I checked all the rubber mounts, they're old but still soft and not loose. My elmer asked me to make sure that there was no play in the mounts besides the rubber flex and no, they're soft mounted but you cant just freely shake the bags or the trunk. I think that little bit of extra weight on that point above the rear wheel is what really makes the difference in the resonance of the bike.

But idk <3 this is srsly such an adventure I wish it didn't make my heart stop every time I learn something new though!

[joecoolsuncle]

secure an equal amount of weight to the tour box platform. if it wiggles, the weight or wind drag from the box is causing front end to unload. if it doesnt wiggle, remove weight, install box. go for a ride without your jacket and move your elbows to different heights. what happens as you make these aero corrections?

[KenwoodFox]

Equal weight also causes wobble, especially if elevated to about the same cg as the trunk.

Elbows? Not so much but I can introduce a bit of wobble by just giving the handlebars a slight bump, its destructive though, it does shake but it only takes about half a second for the shake to decay and return to steady ride, with the trunk/weight on the rear (not a passenger wight, seems to only be fixed weight) the shake and wobble is constructive and it builds up till the handlebars are contacting the maximum steering angles/hitting your legs :c

It happens at such low speed I rly doubt its anything aerodynamic, between 20 and 30ish mph :c

[joecoolsuncle]

move the weight to the front. a passenger will hepl weight the front. the box, and /or the weights on the rear, will unweight the front. an unweighted front will follow lines, grooves etc easier. an unweighted front will also be more likely to move as the wind catches your shoulders, jacket, corners, fairing, yada. something small, and unnoticeable will shake like a dog shatting a peach seed because of the exaggeration of the lightened fork. a rear wheel bearing, swing arm bearing, cracked frame will rear its head more. coincedentally your shake is starting at about the same speed the bike would normally start trying to become stable.......at what speed does the chassis start to lift from wind speed? just some thoughts.

[KenwoodFox]

Lift? ive never noticed lift before, and no yeah the wobble is really extreme, like I mentioned earlier it almost maxes out my steering motion, check the video for an example, its a proper shake, I'm lucky I've not high sided the bike yet whenever it happens :3 for now the bike is back in the garage and ill pull the tank before subjecting anybody else to the danger.

yeah I've never noticed lift before, really happy to hear your thoughts! Im taking note of every input~ The bike is pretty rock solid stable at any speed over 40

you mention wind-catching shoulders, farings, and stuff? Honestly, I've had nearly 0 wind-related backlash on the bike, even on windy days, I don't weigh a lot and I don't have very broad shoulders but like, I personally, have very little input on the motion of the bike, lol, I can stand up over the windshield and it does nothing at all, even shifting my body weight side to side really does nothing. On my 750 my motion/lean is like 60% of the motion of the bike, the rest is countersteer, on the goldwing, my position really doesn't move the bike at all, only countersteer, took a minute to get used to that when coming to a stop, now I always gently turn away from the foot I want to put down since just leaning is not enough.

at what speed does the chassis start to lift from wind speed?

Really curious what this means, thanks so much!

[joecoolsuncle]

the bodywork is aero engineered to provide lift. stand back and look at the sides of the bike. you will see what im talking about. you also feel it when riding. the bike becomes lighter and handling becaomes lighter. at parking lot speeds, the bike is lethargic, wants to be lazy and fall over drunk. as speed increases, the bike (chassis) becomes lighter feeling. this is where seasoned riders start noticing the design flaw, and newby riders notice the ease of turning the handlebars. it becomes so easy in fact that he chassis is not planted, it wanders. this is the problem i am trying to help you adress.

[KenwoodFox]

I can't say ive noticed this, in fact I've noted just the opposite. The bike has a very regular handling at basically every speed, it feels (at least to me, and I'm a total beginner) that it basically handles exactly the same no matter what speed. I notice its moment of inertia a lot more than its apparent mass and hairpinning In a parking lot feels basically the same as rounding a corner at 40 lol.

Maybe I'm not seeing exactly what you're saying, but now I'm immensely curious to see if i can feel that effect at all. Would it show up on my suspension air gauge at all? I've noticed a slight increase in pressure on the front forks when doing 80+, not a decrease as you mentioned. If the body were to make an airfoil as you mentioned to look at, it would sorta.. seem to be inverted? High pressure on top with low on the bottom pushing the bike into the ground at high speed.

Idk! Pulling the rear end off and ordering new bearings now~

[joecoolsuncle]

sorry, i thought i read you had already inspected the rear bearings. now there is info stating the bike handles exactly the same at all speeds!?
this is beginning to read like a blog.

[KenwoodFox]

A little yeah haha, ill post video + summary of how rear bearing replacement goes, plus just, inspect everything under there like some other forum members above said. Thanks again~

[joecoolsuncle]

A little yeah haha, ill post video + summary of how rear bearing replacement goes, plus just, inspect everything under there like some other forum members above said. Thanks again~

yes. now it is clear the bearings were not inspected, maybe return to top of thread. as a note, when you get the rear wheel bearings out, note if there is a hardened bearing insert in the final drive side of the wheel.