Steering damper on an 1100?

beemerphile said:
My PO had a BT045R rear tire on the front of my bike. Not liking the steering, nor the fact that the sidewall was placarded "Rear Use Only" I exchanged it last week for a G547 Exedra. The steering was instantly better, but I also instantly had mild head-shake when hands-off decelerating - something I never had with the "wrong" tire. When I checked the headstock bearings, they were too loose. The wheel fell easily to either side. After tightening it to obtain a couple of pounds of drag on the fish scale, the shimmy is completely gone. I'm in a happy place with it now. I have a set of T31's for my other ST but it may be 6 months before I have it on the road. I need to settle on one tire for both of them because I keep a spare set of wheels with new tires queued up for long trips that I don't want to start with tires that can't make the entire trip.
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I think you'll like the Exedra tires.
People have wandered all over hell's half acre searching for other tires.
Mean while the Exedras give excellent feedback, perform well in the rain, and provide very good mileage.
Meanwhile, summer is fast approaching, have a great one.
 
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John OoSTerhuis said:
Check your front and rear suspension first. Correct OEM ball bearings preload? On the centerstand does the wheel flop to the side stop with little or no input? Fork fluid fresh and at the spec’d levels? Sag set with correct preload? Tire inflated to spec (36psi)?

Rear shock preload set correctly? Damper setting matched? How old/many miles? Swingarm bearings...?

John
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OP, This right here is where I would start. Regular maintenance items first. Even fresh fork oil. Not likely the cause, but I look at it as if the fluid is overdue for a change, why not do it. Bring everything up to spec and possibly fiddle with suspension settings and just see if it makes a difference. Swingarm bushings would be higher up the suspect list, especially with age. Im not saying change them, but check for play. Also, check motor mount bolts. The motor acts as a stressed member of the chassis. Its a stretch but if a mount or 2 is loose, the frame would lose rigidity and who knows what effect that could have and again, it costs nothing to do. Remember that headshake doesnt necessarily have to come from a front end defect/issue, it can come from a rear issue, which you are realizing with your adjusting of the rear shock and the effect it is having.

Edit... and definitely check the tires for runout, both side-to-side and up and down (out of round) and check for scalloping. Im not sure if scalloping will cause a shake or shimmy but severe scalloping is a clue to an issue with the chassis, I would think.
 
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Hondeltor said:
Anybody ever try? Ive searched but not found any specific bracketry. Generic damper kits are plentiful on ebay.
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I plan on putting one on my ST1100 That has clip-on handlebars. I think you have to make your own bracket for it but not sure.. I’m going to try it soon.
 
A bit of ST1100 history - the STrider community has been discussing the “decel wobble” for over 25 years. I first read about it in the ST1100 Newsletter. Here is the article by ST icon George Catt that I used to install tapered roller stem bearings and races in my ‘91 SSMST (page 11) way back in the last century:
ST1100 Newsletter Spring 1994
Have a look at the rest of the Newsletters:

(Stickie) STOC Newsletters by WG Norman *

(Stickie) STOC Newsletters by WG Norman *
www.st-riders.net

“What’s old is new again.” :)

John
 
Thanks John for STeering us to the newsletter from the past. An informative read.
Once I discovered I had a wobble in my first ST. I searched for solutions.....I was told all bikes wobble at certain speeds, it’s the geometry of motorbikes in general. I wasn’t buying it. I had owned and driven motorcycles in the past and when I had this issue I was able to correct it. Granted the bikes I owned had a chain final drive and it was usually the rear axel out by a mm....
Steering head bearings resolved my issue on the first ST. When I felt the shake and wobble on my second ST, I did not pass go, I did not collect my $200, rather I spent the money for my shop to replace the bearings.
I understand the comment don’t take your hands off the bar cause then it won’t shake...sorry not buying that either. That shake is still there, you are compensating for it and it will fatigue you. It will nag at you! ‘cause you know it’s there. When you spend long days riding, at the end of the day you will feel better if that little wiggle is tended to properly.
 
kiltman said:
.... that shake is still there, you are compensating for it and it will fatigue you.
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Maybe we’re talking about a different thing, Robert. I didn’t even know about the infamous “decel wobble” until I read about it in the Spring ‘93 issue of the newsletter... never having taken my hands off both bars after rolling off the throttle and coasting down through 45mph. It only lasts for ~5 seconds and one finger on either handlebar grip (or lightly braking) stopped it. Certainly not fatiguing. And not in any other riding mode. I’m reluctant to admit how many miles I’ve ridden my SSMST hands-off with the AudioVox cruise control on.

OTOH, I have experienced a one amplitude per second ocillation (won’t call it a “weave”) at a GPS indicated 128.4mph on two separate occasions (8 years apart). :rolleyes:
kiltman said:
It will nag at you! ‘cause you know it’s there.
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Well... there’s always that...

FWIW YMMV

John
 
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John OoSTerhuis said:
I have experienced a one amplitude per second ocillation (won’t call it a “weave”) at a GPS indicated 128.4mph on two separate occasions (8 years apart).
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Hi John:

I've also encountered that light oscillation at around 130 MPH, in my case while riding on the Autobahn in Germany. I think it is a result of aerodynamic uplift of the front end of the motorcycle - this really lightens the load on the front wheel. I don't think it is a result of any fault with the motorcycle (design fault or maintenance omission).

I now limit my maximum speed to about 180 - 190 km/h (110 - 115 MPH) in order to avoid this problem. Truth be told, it's not much fun riding any faster than that - too noisy, rotten gas mileage, and all one sees is the painted stripe on the side of the road. For me, the 'sweet spot' in areas without speed limits is around 160 km/h (100 MPH).

Michael
 
CYYJ said:
I've also encountered that light oscillation at around 130 MPH, in my case while riding on the Autobahn in Germany. I think it is a result of aerodynamic uplift of the front end of the motorcycle - this really lightens the load on the front wheel. I don't think it is a result of any fault with the motorcycle (design fault or maintenance omission).
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Having ridden other motorcycles at speeds well in excess of 130mph without any weave I'd suggest there's more than aerodynamics to the equation. Coming from the sportbike world to the ST I'd have to suggest that its handling characteristics are primitive, even for the early-90's when it was introduced. Yes, I know, I've been told numerous times that Honda can do no wrong, so I will wait to be told once again that it can't possibly be a design issue.
 
dwalby said:
Having ridden other motorcycles at speeds well in excess of 130mph without any weave I'd suggest there's more than aerodynamics to the equation. Coming from the sportbike world to the ST I'd have to suggest that its handling characteristics are primitive, even for the early-90's when it was introduced. Yes, I know, I've been told numerous times that Honda can do no wrong, so I will wait to be told once again that it can't possibly be a design issue.
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This statement that Honda can do no wrong, so it can't be a design issue.
I agree that it's not an aerodynamic problem, although it does ad to the problem.
I've also encountered the 'problem' that comes on at about 125mph.
Since I know it's there I simply stay below that problem area.
 
I'd still like to see someone try my suggestion of lowering the rear suspension a tad, which would push the forks out and increase stability.
 
Larry Fine said:
I'd still like to see someone try my suggestion of lowering the rear suspension a tad, which would push the forks out and increase stability.
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My own observations over the years has been if I started with a compromised chassis, shock upgrades and suspension adjustments may help a little, but don't completely solve the stability problem. Conversely, starting with a rock-stable chassis, it didn't matter what shock setting or suspension adjustments I made, it was always stable. The ST1100 chassis is similar to the steel tube chassis of the UJM era, and has handling/stability characteristics common to that era.
 
At 128.4mph I guess it’s better described as a slight rocking motion, +/- 5° or so. Nothing alarming and I didn’t fight it. At that speed on my SSMST1100 I was at its aerodynamic threshold... I still had quite a few rpms to go until redline but it just wouldn’t go any faster. This was in Texas and Nevada, and each time for a sustained period. And with tapered roller steering bearings, Superbrace, fairly fresh Exedras, a large Clearview, 910 PIAAs, mirror/fairing/foot wind deflectors, Fenda Extenda, and 21ltr Hondaline topcase. And me, 5’6” and ‘tucked in.’ FWIW

Edit: Hypothetically of course. And my “sweet spot” seems to be right at 82mph.

John
 
John OoSTerhuis said:
Well... anything new to report? Everyone that has contributed to your thread/issue is “invested” in it and waiting for a resolution. TIA!

John
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Larry Fine said:
I'd still like to see someone try my suggestion of lowering the rear suspension a tad, which would push the forks out and increase stability.
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I’ve tightened the bearing preload to factory specs, dropped the rear shock by one preload click and added 10mm of front preload with new spacers.

Bike feels much better balanced, bar shake is much improved, and is a good compromise between one up or two.

Still need to change that front tire.

Thanks to all for the suggestions.

As an aside, Larry, did you do any good on those GW pegs?
 
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Do keep in mind that many of us, myself included, have larger aftermarket windshields on our ST 1100s, and at very high speeds (120 MPH & up), those larger windshields will have a considerable effect on aerodynamics of the motorcycle.

Michael
 
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