"look ma, no hands"-mistake

[martijn]

I experience a serious front fork "wobble", when I let go of the steering wheel at some 60 km/h (37 mph). Is this normal for the XZ550 or is there something wrong with the bike?
(hints: the tires are getting a bit old and I think she needs an front fork oil-change).
I am told you should be able to let go of the steering wheel at any time with a good balanced bike.

Any thoughts?

Cheers, martijn

[Extent]

That is one of the complaints I've heard about the V, headshake above 25-30 Mph.  This is just starting to bother me, and I was thinking about finding a steering damper to fit to it, but I've got a lot of other things I need to deal with first.  I think I've also heard about swapping the bearings for tapered ones to move the worst of the headshake from 30Mph up to 60 or so.

[GA_Wolf]

Tapered bearings can help, also make sure your forks are in good shape and if it's an 83, make sure your air pressure in the forks are as close as you can get to equal.

even with all that, mine still will try to wobble, especially in a slow/medium speed turn.  Either backing off the trottle or easing in the clutch and it will go away.  This kind of tells me that it's a basic frame geometry flaw...like the pressures on the fork is un equal when the torque is trying to push the bike over the front tire vice a solid thru the front end.

[louthepou]

The "trailing axle" front end is one factor that contributes. Make sure your front tire has even wear; some types of tires enhance wobble tendancy.

I noticed I made matters worse by putting clip-ons on the forks. I wonder if anyone experienced with a steering damper? Anyone?

Louis

[Josh M]

My bike had a bit of wobble.  It went away when I put on new tires and new fork seals.  Headshake is usually an indication of something wrong, worn tire, bad fork seal, worn head bearings, etc.  If everything is OK, there should be no head shake.  I can take my hands off the bars at any speed(over 7mph) and the bike will track straight.

[Superfly]

I was having the same problem, put on new tires, I had an extra set of forks (set really stiff) and added a daytona fork brace, I have ridden hands-free a couple of times.

[Riche]

If you feel you need to go to a steering damper you could try the one supplied with the old Kawasaki triples. In the early 80s one of my riding buddies had one on a 750 Triumph. He said they were a popular add on for guys going to short bars like he had done. There could be a better/newer solution. As has been stated making everything right along with maybe a fork brace rids you of the wobble. With short bars it may not be enough, making a steering damper necessary.

[kiawrench]

if you feel the need to release both grips at the same time on a vision, it is going to shake, no matter what you put on it .
this is a design/physics flaw. a trailing axle will vibrate in motion and no amount of add ons will stop it .
 ? you can reduce the wobble ,spend a good bit of money and almost eliminate the shake, but just by simple laws of physics, it is still there.
 prove this to yourself without endangering fellow travelers,,,, go to a store, grab a buggy and just push it down any aisle,,, let go of it and watch the front wheels wobble. trailing axle and the laws of physics in action . on a vision, this is compounded by the rider and acceleration /deceleration. best bet, keep hands on the bike, leave tricks to indian larry,,,, oh forgot , he killed himself doing stupid tricks on a motorcycle . ? sorry if anyone offended,,,, just hate to see good riders and great bikes hurting each other ..

[Walt_M.]

Motorcycle handling and geometry is truly an art. The original Vision road test in Cycle magazine mentioned hands-off front end wobble. They said some Visions wobbled and some didn't. My '83 did when new, it went away when I put on Dunlop Sports Elites, 110/90 front and 120/90 rear. When I resurrected her last year, I went cheap on tires, IRC Durotours in the same size, now the wobble is back, even with a fork brace. The 'trailing axle' fork is probably a 'fix' the engineers tried during development. They probably had the frame jig made and the triple tree castings done and the fork legs were probably the easiest things to change to get a little more trail. Does this story have a moral? Yes, some Visions wobble.

[louthepou]

The trailing axle is indeed an easy trick - to get quick steering. But there's always a tradeoff.

On the opposite side, a leading axle gives a stable ride, but heavy steering.

I agree with you, Walt - a lot of art involved. And a lot of cool science too!

[silicon_toad2000]

Maybe I'm just lucky with my bike, but i have gone no hands from 110kmph until it reached about 50 kmph and became a bit hard to control by only throwing my weight around (I had to actually steer the old girl).
I think I'll be keeping my fingers crossed that the problem doesn't develop over time.

[Lucky]

No, .... I'm Lucky.  lol

[Josh M]

Sometimes it's hard to adjust my gloves while keeping one hand on the bars. ;)  I like to know that my bike is stable for the rare moments that my hands may be off the bars.  

[Walt_M.]

It proves how much motorcycle handling is 'art' by the number of people who think the trailing axle quickens steering. It is just the opposite. Moving the axle farther behind the point where an imaginary line through the steering head would touch the ground increases 'trail' and makes the bike slower steering.

[Lucky]

True enough, I thing sometimes people confuse 'quick steering' with quick return to center.. (caster)

--Lucky

[louthepou]

OK guys, seeing I definitely understood a lot less than I thought, I found the following...

http://www.american-v.co.uk/technical/handling/geometry/body.html

I do encourage all of us that posted in this string to take the time and at least have a look.

Enjoy the reading!

Louis

[martijn]

Gee, guys ...
lot of info out there ! thanks. I'll start with new tires...

cheers, martijn

[silicon_toad2000]

i had always thought that they said steering was quicker with an increased trail as it shortens the wheelbase and tightens up the turning circle. but quicker is not really the word is it.

[Riche]

Martijn

When you change your front tire make sure you check you wheel bearings. Worn bearings will add to the tendency to wobble as will loose stem bearings. My machine has no wobble. It has fresh Avons, good wheel bearings, no slop in the stearing head and no fork brace.