ST1100-Worn suspension bushings - symptoms and wobbles?

Animal Mother

Animal Mother

Joined
Sep 25, 2009
Messages
43
Location
North Wales, UK
Bike
ST1100Y
I've just had some new tyres fitted and this has thrown up a wobble through the handlebars.

Now, the bike already had a slight wobble through the bars anyway but I put this down to the old front tyre which had some strange lumpy wear on it. Now it seems that the strange wear on the tyre is a result of the wobble and not a cause. That old tyre had obviously worn in such a way to minimise the wobble. However, now that it has a new tyre the wobble will be back with full force.

Other things I've checked are:

1. Steering stem bearings - fine.

2. Wheel bearing (front and rear) - fine.

3. Swinging arm bearings - fine.

4. Front discs - fine.

5. Front wheel runout - fine.

6. Front callipers - fine.

7. Triple tree/fork clamp bolts - checked, not torqued properly, re-torqued now fine.

8. Movement in the fork casings - yes. A little play in the right hand fork and more in the left hand fork!

Is there supposed to be any sort of movement/slackness/play in the front fork casings?

Would this movement in the fork cause wheel/steering wobble?


Thank you.
 
My ST11 had a bit of play in the bushes but no wobble. Also had notchy steering bears no wobble. Some bikes do get a shimmy, especially on deceleration around 60kph or so. Tyre balance is an obvious area. What tyre is it?
 
One of the big causes of front end wobble is REAR suspension settings. Try adding some preload to your rear shock spring.

I changed the rear shock to a Progressive Suspension model and added some preload; front wobble nearly gone.

It does change with tire wear, too. As my front tire approaches end-of-life, the decel wobble will get worse. Nothing I can't handle; just keep at least one hand on the bars!
 
There are a lot of posts about people that have this with Avon Storms. I have it on my 1100 when coasting through 45-40 MPH. I don't notice it maintaining speed in that range, braking through it or accelerating through it. Only while coasting.

Can you give more info on your issue. What kind of tire, is that the same kind of tire that was on the bike before, under what conditions does it happen? As for strange wear. It might be cupping or scaloping. This is normal for tires on these bikes. It is going to happen near the end of life but can occur more quickly if you are not running proper air pressure.
 
The tyres I've had fitted are Avon Storm 2 Ultras. It had Metzellers on it previously.

Tyre pressures are 36/42.

The wear on the old front tyre was lumps either side of the centreline. As though some sort of oscillation had caused it.

I did some further checks too:

1. Tyre's are all mounted correctly.

2. All wheels, tyres and discs run straight and true.

3. Spring pre-load is set to position 3.

4. Damping is set to 180 position (to match pre-load) as per http://www.pan-europe.utvinternet.ie/owners_manual/major_components.htm

5. Bushings on rear shock are all good.

One thing that was mentioned to me is my large screen (larger than normal) may cause the wobble.

This is the bike with the screen fitted.

73134.jpg
 
Most people run 42 front and rear. Also what speeds does the shake occur? Any speed, a certain speed range, a certain condition (braking, accelerating, coasting)?

So far the fact that it is an Avon and you haven't run Avon tires in the past makes me think it is the same thing many of us have felt in the past. The had shake I get is really minor. I feel it in the bars but can easily control it with only one hand on the bars. Is this the condition you have?
 
Take a look at this thread.

Linky

Here is another link. This one talks about uneven tire wear and cupping. I think that cupping is your issue with your old tires. Take a look at the photos and the section of the site that talks about cupping to see if that is what you are talking about when it comes to the "lumps" on the old tires. It might be a sign of something else but I want to eliminate the "known issue" of cupping tires. There isn't much that can be done about it as it has to do with the weight of the bike and the way tires work.

Link
 
It occurs most severely at 30+/-5mph and 50+/-5mph.

It doesn't increase in severity when braking. I happens when riding at a constant speed or accelerating.

I tested the suspension as per http://www.wpsuspension.co.uk/setup.php and all appears to be in order.

According to the website you linked to the old tyres were scalloped.

I'll take a look at the incorrect tyre pressures. Thanks for pointing that out.

I've just bought a new set of bushes, oil seals, a set of Hagon springs and some oil. I'll get the forks rebuilt anyway as it will only improve the bike whether it cures the wobble or not.
 
sennister said:
Most people run 42 front and rear.
Click to expand...


In the US maybe but not in the UK..... 42 is too high for the ST1100 front, it will not allow sufficient tyre flexion in corners to provide the grip levels required, reducing the contact patch is not good.
I have had some sliding at 40 lbs/psi so run around 38-39 in the front. My bike has an ABS/TCS and 36 is too low in the front..... it causes uneven tyre wear and reduced mileage.

The 1100 can be quite sensitive to tyre pressures, either too high or too low.
 
I haven't heard that a large wind screen will cause a wobble; but, it will *really* cause a decrease in mpg.
It STill might be the culprit though; try taking it off (or borrow a stock shield) and ride up to your 2 speeds (and for a tank to check the mileage effect).
 
Big Red said:
Did you have any issues before the new tyres were mounted?
Click to expand...

Yes. A slight wobble, I put this down to the bad wear on the original tyres (I've not had the bike long and bought it with those tyres on).

After fitting new tyres it seams that (possibly) the old tyres had worn in such a way to mask any severe wobble.
 
It passed its MOT today with flying colours. I got the chap to concentrate on front and rear bearings. He said it's all fine.

If a front fork rebuild doesn't resolve it I'll just have to live with it.
 
Perhaps its the roads, or maybe you are tensing up looking for little things. Try relaxing and enjoy the ride. Its a bit like encountering strong wind gusts, just relax and let the bike take care fo things, fight it and you have problems....
 
Avtrician said:
Perhaps its the roads, or maybe you are tensing up looking for little things. Try relaxing and enjoy the ride. Its a bit like encountering strong wind gusts, just relax and let the bike take care fo things, fight it and you have problems....
Click to expand...

That's a very holistic outlook you have on things.;););)
 
I have the Storm Ultra 2s on mine as well. 36 psi front 42 rear (42/42 is an ST13 thing, although I found the Z6s liked 38 in the front) Apart from waiting until the tyres have worn into the bike, hard to say what might stop a wobble like that. Some bikes do it, some don't. perhaps try loosening the axle and axle mount bolts, bouncing it a few times o the front, then do them up again. May help align things, which again seems to be a trick from the ST13.

It is a frustarting issue, but unfortunately I have not had to solve it. The Suzuki GT750 I owned had it, but it wobbled at speed as well :)
 
Thank you to everyone for the posts.

My new Hagon springs have arrived now.

The front fork are being treated to Springs, oil, bushes (bushings), seals and o-rings. Plus a general overhaul by Kais suspension.

If that doesn't resolve things then I'll just have to live with it.
 
I've got the front forks back now. I went to fit them and discovered that my lower yoke is damaged.

It seems a crash earlier in its life has damaged (bent) one of the fork clamps on the yoke.

So, I replaced the bottom yoke with a spare I had and re greased the bearings while I was at it. Everything is back together now and I'm going to go for a test ride tomorrow.
 
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