I got a Wobble!

[biffo]

New to site so hope this is the right place to ask.
My 900 has developed a wobble between 3k and 5.5k revs, so I just HAVE to go fast to stop it. Have changed both tyres and had them balanced. Had rear end dropped and examined but no obvious defects. Is there a well known fault that I can get resolved. Bike Dr says he thinks there is a balance problem with engine or gearbox but revs as sweetly as usual and gear change its usual chunky self, so don't really want to part with too much hard earned for a rebuild. Any suggestions, preferably about the wobble, would be appreciated.
Biffo
aka Phil B. Essex boy and born again biker.

[cam7777]

The wobble is usually speed related, both of my 900's wobbled at 35-40 mph regardless of top box fitted or not.
New tyres should make matters better (provided they are balanced) for a short while until they wear again.

Like the carp headlight, it seems to be a feature of the dear old diversion, it gives it character i think

[griff]

Mine wobbles too mate! Have to have a reasonable hold of bars when riding - doesn't like one handed riding much.
Sounds like it IS a feature.....

[neilmud Lord Protector]

Sounds like the 40mph wobble you will find all sorts of answers on this site in other threads.
I found it useful as mine only did it when tyre pressure was low so I knew when to pump them up.
And it a lot easier than some of the other ways to stop it though I would check head bearings before just pumping up tyres if this doesn't cure it get a Fazer
Neil

[biffo]

Thanks for the advice. Lower speed journeys are the worse, M25 in rush hour at speeds 50-60. If I can keep revs over 5.5K and cruise around 80ish all is well, but if not, the old circulation tends to stop, especially in the left hand. If it's a feature, I'll have to live with it.
Thanks again.
Phil

[max900]

if you have circulation problems with your left hand then either your carbs need balancing or you are gripping the hell out of the handle bars ;D
as for the wobble as others have said its speed related anything between 30 and 50 mph but it only really shows itself if you relax let go the handlebars ;D
its been blamed on
Tyres(aswell as wheel/tyre balance)
steering head bearings
front forks oil/springs
and rear shock
aswell as
Topbox
however most of the time simply fitting new tyres virtually cures the problem :-/but only till the tyres have worn down again

[cam7777]

UPDATE*
My latest 900 wobbled pretty badly around 40 MPH, had to grip the bars very tightly, the front tyre looked fine (Continental road attacks ).

Just changed the tyres for Bridgestone BT021's and wobble has completely gone, I can now ride no handed[1] without any twitching whatsoever.

HTH

[1] Please, please dont try this!

[teejayexc]

cam7777 said:

UPDATE*
My latest 900 wobbled pretty badly around 40 MPH, had to grip the bars very tightly, the front tyre looked fine (Continental road attacks ).

Just changed the tyres for Bridgestone BT021's and wobble has completely gone, I can now ride no handed[1] without any twitching whatsoever.

HTH



[1] Please, please dont try this!

Will expect you whizzing by me with both hands tucked behind your head now then?

Trev

[El Fuego]

Mine wobbles if I let go with both hands. (Starts as a gentle wobble and grows to tank-slapping proportions if I let it). One handed riding is fine though.

[CD]

My suspicions would fall on the swing arm bearings and steering head bearings. But a worn rear shock can do strange things. My 900 rear shock was fine on a bounce test with no leaks but the bike had a slight weave at M-way speeds but not enought to worry about. I fitted a used WP shock aquired at a bargain price and the speed wobbles went away. I also realised just how horribly harsh the old shocker had become.