speed wobble

[DJones]

My `79 Gs1000E`s front end wobbles and feels very unstable at 50 mph or higher. Is this normal? There doesn`t seem to be any excessive play in the steering head. The forks have 14psi and the rear shocks have preload setting of 3 and damper setting of 3. Please help!

[KGB]

How much air is in the front tire?
Is it at the pressure on the tire,not in the manual?

[Billy Ricks]

Could be tire balancing, loose or worn steering stem bearings, wheel alignment, or just an unevenly worn front tire.

[KEITH KRAUSE]

Re: speed wobble

My `79 Gs1000E`s front end wobbles and feels very unstable at 50 mph or higher. Is this normal? There doesn`t seem to be any excessive play in the steering head. The forks have 14psi and the rear shocks have preload setting of 3 and damper setting of 3. Please help!

I have a '79 GS1000E and after I replaced the steering bearings with new ones, I had a bad wobble starting at about 70 mph and it got worse with more speed. I thought I had adjusted any excess play out of it and still be able to turn the bars smoothly side to side. I decided to give it about 1/8 turn more and it got better. I gave it another 1/8 turn and it completely went away. The bars still don't have any noticable drag. It's amazing what 1/4 turn will do to the steering. I had also replaced the swingarm bearings and had new shocks/fork springs/tires, so I was surprised when I had the wobble.
Anyway, the most common cause of wobble on these bikes is loose steering bearings.
PS: if you tighten the steering a little more, put the bike on the centerstand and also loosen the upper fork tube pinch bolts before tightening the steering nut. This will eliminate any chance of binding.

[mdole]

Could be tire balancing, loose or worn steering stem bearings, wheel alignment, or just an unevenly worn front tire.

One thing to check that could cause this that hasn't been directly mentioned is cupping on the front tire. I've had the front tire cup on some of my bikes that caused this sort of shimmy or wobble. I tried a Avon on my Sabre one time that was a sticky tire to see if I could get some better handling and it worked really good of about 2500 miles and then started cupping and the front end developed a 50 mph shimmy. It got worse and by 3000 miles the shimmy had moved to 70 mph and the amplitude had increased a lot. I went from an annoying shimmy at 50 to a scary shimmy at 70.

New tires fixed the problem and even though some tires are more prone to cupping than others I think that due to the differences in front end set up that its a sort of bike specific thing. I had run the same tire on a Triumph 750 special and had no problems with it but the Sabre put more of a load on the front end and the tire didn't work at all.

Mike

[mdole]

Another thing about cupping is that it can also be caused by worn front-end components or misadjusted steering stem bearings.

If you find cupping you need to check that you don't have a problem with the shocks, wheel bearings, or steering stem bearing. Also check tire inflation pressure and balance.

Mike

[Don Lobacz]

Front wheel bearings need checked periodically too.

[Clone]

I'm going to tack my problem onto this thread. I have the opposite problem, my bike wobbles from side to side at low speed, less than 20km/hr. I looked at the front tire which is relatively new and noticed that it was alternately worn from one side to the other. within lets say 18cm, one side is worn, then about 9cm later it looks new and the other side is worn. Why? The steering head is tight, I like a stiff front end so I have a lot of pressure in the forks, I am really hard with the front brakes, so apart from using the back brakes more what would cause this?
Can I use a grinder to scrub off the uneven wear as suggested by the shop?

[Billy Ricks]

Clone,
Somehow the balance of that wheel got off. It's probably too late to do much about it. If you want to experiment you might feather off the wear. Just be careful on that tire.

[Anonymous]

clone, sounds like the steering head bearings are over tightened. this makes the bike seem top heavy and not want to go in a straight line.loosen up a little and see ozman

[DJones]

speed wobble

I checked the air pressure. 20 psi in the front tire 35 psi in the rear. increased the front air pressure to 28 psi. speed wobble still there. Will try retorquing the front steering bearings. Is there a special tool needed to do this?

[KEITH KRAUSE]

Re: speed wobble

I checked the air pressure. 20 psi in the front tire 35 psi in the rear. increased the front air pressure to 28 psi. speed wobble still there. Will try retorquing the front steering bearings. Is there a special tool needed to do this?

I use my Suzuki steering stem wrench. It has a curved end that fits around the nut and the tip of it fits into the notches in the nut.
Some people just use a large flat screwdriver or similar and place it in the notch and hit it with a hammer. Then re-torque all the bolts.

[Anonymous]

Anybody know roughly how many miles to replace wheel bearings? Every....?
Mine are 26 years old at 20k.

[daveo]

Anybody know roughly how many miles to replace wheel bearings? Every....?
Mine are 26 years old at 20k.

on a tapered roller (not ball) bearing, there is a chamfered shoulder on the rollers themselves, when this chamfer is no longer apparent it is time to replace

[mcconnell]

The wheel bearings are ball bearings on the front wheel of our GS's. How long do they last? My 1973 GT750 had the originals in at ~120k miles. My 1983 GS1100 (I am the original owner) needed new ones in less than 20k. I found they were shot by the wobble at 110mph. They were so badly worn the wheel broke the 'ears' off the speedo drive. I don't think they had any grease in them from the factory. Ordinarily, I grease them at every front tire change.

Put the bike on the centerstand, have someone hold the back of the bike down so the front wheel is elevated. Have this same person hold the handle bars against one steering lock. Try to wiggle the front wheel side to side to see if there's any play in the bearings. (check for steering head bearing play while the wheel is elevated, too). Then pull the front wheel and put your finger in the bearings and see if they turn easily and smoothly. If so, pry out the dust seals and repack them with a good water-proof wheel bearing grease.