high speed wobble

[ticker59]

Can anyone help, I have a 1400 moto-guzzi california that I absolutely love with the exception of that at speeds in excess of 95 mph the front wheel starts to weave getting worse as the speed increases above that. I have done the obvious, wheel balanced and tyre pressures, what else should I be checking? At slower speeds it behaves perfectly.

[scorcher]

Suspension set up? Brand of tyres? Panniers fitted? Type of screen (if) fitted? Common trait, so TADTS?

[billinom8s]

Steering head loose?
Rear wheel out me balance?
Rear tyre worn uneven?
Low front tyre pressure?

[TLS-Moose]

Do you have the factory (fork mounted) screen fitted? If you do, thats possibly the start of your issues ....... If you don't have the screen fitted, try relaxing your grip on the bars a bit. Quite often with naked bikes the main cause of instability is the rider. Any loads placed on the front end of the bike have a profound effect on stability, and a fork mounted screen, or a rider (out in the wind being buffeted) gripping the bars tightly will set up a weave quite nicely .......

As said, tyre pressures and wear, wheel/swingarm/head bearings should also all be checked.

[Bullet]

Wel I've no bloody idea apart from Don't drive over the speed limit! Simples

[ticker59]

Thanks everyone, I do have the factory windshield, panniers and topbox fitted so will unbolt them and try running it naked, if that doesn't sort it then it will be checking the swingarm and headstock bearings. However, I don't suspect these as these were checked less than 500 miles ago. Already checked tyres for wear and pressures and had them balanced, maybe i have lost a balance weight. Once again thanks for the advice.

[ptolemyx]

Are either of the tyres worn? Sometimes a front that looks "part worn" is bad enough to lose the fresh tyre high speed stability.

[badgerKDD]

As I don't know the model can I ask is it Chain drive or Shaft? If chain drive, check the sprocket carrier bearing as well as the rear wheel bearings and check for wear on the Cush Drive rubbers. Often problems at the rear will affect front end stability.

[podrick]

I would of thought the top box is the most likely culprit.
Try removing that first

[Gimlet]

Is it running the standard tyres? When I bought my KTM it was fitted with Racetecs which were very twitchy unless really warm. I changed them straight away for some Metzeler Z8s thinking they would suit a long trip I was planning. I struggled with the handling. There was little feedback, a harsh ride and the front end was unstable at speed, always threatening a tank slapper. Because I didn't know the bike well I tried everything before I came back to the tyres. Removing the handguards helped but not much. I changed the screen. I spent hours fine tuning the suspension to try and dial out the wobble. I played with tyre pressures.
Then someone on the KTM forum said you've got the wrong tyres mate. Try Dunlops. So I did. The front end was immediately calmed and the bike was transformed.
There was nothing physically wrong with the Metzelers, they just didn't suit that bike. No matter what type of bike it is, its amazing what strange evils can be caused by the wrong tyre choice.

If you are running stock tyres and suspension settings, I would suspect headstock and/or swinging arm bearings.

[ticker59]

Thanks everyone for all the possible things to look at, went to NEC and spoke to Guzzi rep and have been advised it is probably the screen or the replacement tyres so i will go down these avenues using the occasional odd dry day to try and sort it as high speed, wobbly front end and rain are not my idea of fun.
P.S. (santasonabike) Great ride out Sat 5th Dec

[billinom8s]

At least you have multiple directions to take with looking for a solution.