Wobble at higher speeds?

[Bonnie850]

I've been finding that my Bonneville starts wobbling slightly at higher speeds on occasional stretches of dual-carriageway and motorways, usually at about 80-85mph. I'm in a more forward-leaning position than on the stock bike with its high handlbars (as I've fitted original M-bars and peg-adjustors, with a small Givi screen), but the extra weight over the front wheel doesn't seem to be making much difference.

The wobble also seems to start earlier when I hit turbulence from vehicles ahead, especially lorries, but isn't so bad when I'm accelerating at higher speeds (rather than slowing down).

What could be causing this, and is there any kind of cure - short of buying a bigger, heavier, more powerful motorway-muncher?

[wiltshire builders]

Hey, they make the new Bonnies just like the originals then!

It could be you. Are you tensing up? Any slight wobble through the bars will go through you and back into the bike and so on. Relax your grip and drop your elbows so that your arms are acting as dampers.

[alanTDM]

Hey, they make the new Bonnies just like the originals then!

Seems so. But some oldies had a damper rod that you screwed in,which went down through the headstock to cure the wobble.
Might be headstock bearings being slightly slack.

[smellygerm]

Could be a number of things maybe the tyres? :-?

[Bonnie850]

Thanks for the feedback so far. I've just ordered a set of steering dampers from Norman Hyde (so its obviously a known problem then!?). As the bike is still almost new, its unlikely to be worn bearings or the suchlike, but he did mention a couple of other things to check: wheels not perfectly inline or properly balanced, tyre sidewalls not evenly fitted?

[NiteW4tcher]

this may sound stupid...............but have u checked your front tyre for damadge? rips, buldges, etc etc??

[pilninggas]

Do you have any luggage/ racks fitted?

sometimes these will just unload the front-end enough or create unexpected aerodynamic forces to allow a wobble or oscillation.

[Bonnie850]

Do you have any luggage/ racks fitted?

sometimes these will just unload the front-end enough or create unexpected aerodynamic forces to allow a wobble or oscillation.

Yes, I do. Of course the problem is worse with loaded panniers attached, and presumably should be worse still with a pillion-passenger - but then surely then some of the extra overall weight will transfer to the front end, loading it sufficiently?

[Mark_Able]

Three causes of wobbles that I've experienced.

1. A screen that is mounted to the handlebars. Any buffeting has an effect on the bars.
2. A top box/panniers, that took weight off the front, and seemed more prone to cross winds.
3. Pulling on the bars at higher speed (without realising) is probably the biggest culprit. Grip the tank with your knees, use your back to lean yourself forward. Try to be as relaxed on the bars as possible.

Of course, it could be none of the above, and just be down to the Trumpet... [smiley=happy.gif]

[wiggy]

Id drop the screen off and try again