Handling issues around 70 mph

[ST4Sal]

Not sure how to describe this at approx 70 my well used st 1100 with 200k on it has developed a wobble. It's strange because the bike will be fine and then it feels as though a giant blast of wind hits it from the side. The HANDLEBARS have no vibration and THEY do NOT even Move. It's scary as hell. After replacing both front and rear rubber and even trying different tires the problem still exists. The shaft drive and spline look great. Shop has had it for the entire year and they are stumped.

findings: parts # 21 shows wear. Part 8 shows wear (actual mushrooming) on the "fingers" the actual wheel shows a razor sharp edge by where the bearing seats but the bearing is fine.


I'm truly hoping someone else has experienced this and has a solution. I can tell you this IT"s Freaking SCARY as hell.


THANKS!

PIECE, DAMPER WHEEL shows wear on the fingers

 

[Uncle Phil]

First guess would be wheel bearings or something is wallowed out, loose or broken.
Miles on the rear shock (ST1100s are only good for about 50,000 miles)?
Steering stem bearings been replaced?

 

[ST4Sal]

Thanks, Rear shock was replaced 10k ago I believe its a wilbers( I know it's purple (I'll verify it )) . Steering stem replaced about 30 k ago. It's important to note the front end is very stable.
When I posted this I was hoping you'd reply


THE REAR SHOCK : HYPERPRO.. sorry for the confusion.

 

[kiltman]

There may be debris inside the spokes of the wheels. Do a slow spin of each wheel to hear if it sounds like sand sliding from one end of the spoke to the other. (It shouldn’t do that)
Make sure the front wheel has been set properly. After the tire change and before you tighten the pinch bolts on the axle dive the front forks a couple of times the torque the bolts to the proper setting.

 

[Bmacleod]

Check swingarm bearings

 

[Uncle Phil]

My Wilbers are black - usually the 'stocker' is blue IIRC.
Swingarm bearings could be it as BMacleod suggested.
I have the 'secret' to getting the front wheel set properly is to tighten and torque the front pinch bolts last.
Are the bolt heads on the plate that holds the rubber shock bushing worn by any chance (usually a bad rear wheel bearing)?
If it only does it at 70 mph, does it go away if you speed up or slow down by any chance?
It could be some sort of harmonic reaction if it is only at one speed.

BTW, my experience with Honda shops these days is that they are clueless about ST1100s and most of them don't even want to work on them.
If they can't plug in a computer to the bike so it tells them what is wrong, they are stumped!

 

[dwalby]

I have the 'secret' to getting the front wheel set properly is to tighten and torque the front pinch bolts last.

there may be some cause-effect here.

Years ago, whenever I was touring and had a removable luggage rack mounted onto the rear tail section, and a rather large duffel bag on the rear seat, my ST1100 would develop a 'weave' at speeds around 75-80mph or so. Without the rack/bag it was OK. No suspension adjustments made any difference.

I seem to have noticed that after doing the front fork/wheel bolt tightening sequence as UP mentioned, where you torque the axle first, then all of the pinch bolts last, that I never noticed it happening again. Prior to that I would torque one side of the pinch bolts first, to keep the axle from rotating, then the axle, then the remaining pinch bolts.

The caveat is that I don't tour as much as I used to, so I don't have a lot of data to support my claim, but it did seem to make a difference in the limited amount of times I was able to observe it. Seems odd that such a minor thing would make a difference, but I think others have made similar claims over the years.

 

[jfheath]

The issue with the pinch bolts is that the axle has to be pulled across to the right by the axle bolt so that the shoulder on the axle can clamp together the speedo unit, the left bearing, the spacer tube, the right hand bearing and the right hand spacer. If you tighten the pinch bolts first, the axle cannot pull all of the parts together - and you end up with a wheel that is able to slide on the axle.

But assuming all of your spacers are correctly installed, that is less likely on the rear wheel. Nevertheless, you don't tighten the pinch bolt until the axle is torqued fully.

Its a long time since I worked on an 1100, but I seem to remember a distance collar that fitted into the final drive hub from the left hand side when the wheel was out. It looks cylindrical, but mine would only ever fit correctly one way round, the other way, it didn't seat properly. I think one end was textured slightly. Someone will correct me if my memory is wrong or if this was a feature of only my bike.

I haven't got a clue what the cause of the problem is from the description but I know where I would start to look. So I will throw out some ideas to investigate as possible causes.

• Wheel bearings and final drive bearings. They wear and collapse over time. If they haven't been done that you know of, they might be a good starting point. Check the shop manual carefully to see which wheel bearing has to be driven in first. It matters, and it may be different for front and rear wheels.
• Wheel balance. You've just had tyres fitted, but if wheel bearings have collapsed the balance will probably be out.
• Pivot bolts and bushes top and bottom of the rear suspension unit
• Swing arm bearings. You need the correct tool to get these tightened properly. Too tight is even more frightening than too slack.
• Tyres unsuitable for the weight and suspension of the ST1100. Go back to Bridgestone - tried and tested with ST1100. Sidewall performance - it is important that manufacturers match this with the suspension for these heavy beasts. Bridgestone do. I dont know about others.
• Swinging arm integrity - these things can corrode from the inside.
• Shock absorber damping adjustment.
• Front fork alignment.
• Shaft drive casing - 4 bolt attachment to final drive housing
• Steering head bearings.
• Rear brake caliper bracket and stopper bolt in left swing arm. Just 'cos it would be stupid not to check that this is fitted correctly !

Afterthought - When /if you get to check the swing arm bearings - just make sure that there is nothing that is preventing the swinging arm from rising and falling through it's full range of movement. It's a wheel out and suspension detached job.

 

[nicksacco]

You may want to reach out to Larry @Igofar

 

[Upt' North]

What you are describing sounds very much like weave. But at those speeds it shouldn't happen unless something is seriously amiss. It can be induced by running with incorrect tyre pressures, badly worn tyres, badly set up suspension, wear in swingarm bearings, in the case of the ST1100 a swingarm which is about to disintegrate with rust, etc.
Can you reach out to someone on the RAN list near to yourself who could take a look and give some input. If your bike is this bad then something obvious is very wrong. I know you've changed them more than once but what tyres are you using and pressures etc.
Good luck.

Upt'North.

 

[Jethro]

park it. No idea what the problem is ,other than the excellent input you have had.

 

[ReSTored]

Just a comment, after tightening the axle nut to spec. (64 lb ??) with the wheel on the ground you then pump the front suspension to seat the axle before tightening the pinch bolts. Unless I missed it, I didn't see this mentioned above.

As above, I'd look at bearings in wheels, swingarm and steering stem. You mentioned steering stem bearing had been replaced, is it possible the locknut has loosened slightly and the torque setting for the bearing has changed?

I'm no expert, but I'm inclined to think your issue is most probably in the front of the bike, not the rear.

 

[Igofar]

While it could be either end, since the rear wheel drives the bike, I would want to know what kind of bearings, and procedures were used on the steering stem.
If just the bearings were replaced, and not the races, it could be notched (why it does not move at all in wind) it could be hunting.
What kind of pressure is he using on the grips?
Standing by the white courtesy phone if needed.

 

[ST4Sal]

While it could be either end, since the rear wheel drives the bike, I would want to know what kind of bearings, and procedures were used on the steering stem.
If just the bearings were replaced, and not the races, it could be notched (why it does not move at all in wind) it could be hunting.
What kind of pressure is he using on the grips?
Standing by the white courtesy phone if needed.

Thanks.

 

[Sunday Rider]

Any update on this?

 

[Sunday Rider]

I see you are looking for a rear wheel. Hopefully you’ve found the problem.