Mid Corner Steering Wobble going over bump

After putting over 120,000 miles on my 5th gen VFR, I bought a 6th gen with 15,000 miles. I notice that when leaned over into a turn and encountering a bump or ridge in the road, the handlebars will wobble a few quick times before settling down. A wobble in a lean is not a good feeling. To be clear, the wobble is definitely in the handlebars and front wheel, not the entire bike wobbling. I'm concerned enough that I have to be much more conservative in curves/turns. I changed the fork oil and verified tire pressures. The bike tracks fine if I take my hands off handlebars while riding in straight line. 30 years of riding over 250,000 miles I've not had to deal with this type of problem. So I'm thinking it could be steering head bearings or something else. Any thoughts? Thanks for your help.

 

I'll ask the obvious question first. You aren't holding on really tight are you?

 

What you describe sounds more like a damping issue, and you may be better off getting in touch with an expert like Jamie Daugherty, but you may want to check a few other things first.

Put bike on centre stand. Put pillion or any other suitable deadweight on rear seat to get rear wheel touching down on the ground, and raise the front wheel clear. Slowly move bars several times from lock to lock. Does it require consistent force to move? Is it smooth? If there are any noticeable points where the bars seem to catch or don't move smoothly you may have your answer. But before blaming the bearings make sure you examine carefully all the wires and plumbing just in case something is snagging.

How much do you know about the bikes previous history? Obviously the previous owner may have adjusted the fork damping settings to suit them, can we assume you have reset everything to standard and then adjusted things to suit your weight and your riding style? If not perhaps you should.

Are the bar end dampers loose? Perhaps most worrying - has the bike had a spill - enough to result in things like the forks getting tweaked or one leg moving slightly higher in the triple clamp - as that sort of thing can give rise to nervous handling?

Whilst the bike may have only 15,000 miles, if its a 2002 6th Gen we are talking about, then it is getting on for 12 years old and if at any time water got into the steering bearings, then rust can easily create problems.

Take care



SkiMad

 

Doh - getting trigger happy - I forgot to say check the front wheel bearings are OK. The tyre has no defects, and the wheel is fitted properly.

 

Also how old is the front tire. I have seen perfectly good looking tires but are so old they can cause all sorts of handling issues.
Dont forget to check the rear of the bike as well. Like suspension settings, condition of the tire, air pressure and if the previous owner might have put to much of a spacer on top of the shock. Just saying that many times the conditions or set up of the rear of a bike can have dramatic symptoms in the front of the bike.
Really hope you get it sorted out because what you describe can be very un-nerving and dangerous. Good luck with it

 

Has the front or rear been changed in height? It sounds almost like a mild tank slapper. If the geometry of the bike has been changed it can be more prone for this to happen. I'd do what the above guys said and check if the forks and see if they are up through the triple higher than stock. I have found the 6 gen to be very stable.

 

Steering head bearings. Either loose and or bad. Check to see if they are notchie feeling when turning. Must have front wheel off ground. If they feel fine then check the torque on them they may be to loose. Should be 18 lb for ball bearings and 10 lb for roller bearings. There is a proper procedure for getting the bearing races "squared" in the frame. If you don't know it then read this http://www.motorcycleproject.com/motorcycle/text/shucking.html. This is for both ball and roller type.

Also check for proper air gap, fork oil height. If one is low it will cause the same as you are feeling. Does it kind of wobble/wander in high speed curves, not corners as much, more in sweepers at 60-80mph?

 

Thanks all for the advice. I started looking at the steering head bearings and they seem to be loose. I use the hammer and screwdriver methods to tighten them down a bit. Took it our for a ride and things feel better. I'm going to check using the fish scale/weight method to verify the preload and adjust accordingly. More to come. Thanks again

 

if it hasent settled completely look at the forks, nervous cornering, especially slow side street cornering is mostly old fork oil or not enough.

 

Don't forget a bad rear shock can cause what you're describing.
Too soft a spring and not enough damping can make the rear go up and down too many times after a mid corner bump and affect your steering geometry, this in turn will make your front wheel go left, right, as it tries to correct itself.