Speed wobble

[anparkinson]

If I take my hands off my bars on my 550K3 at between 40 - 50 mph the bars start wobbling until it wants to tank slap.

I have checked the wheel alignment, had both wheels rebalanced, checked and adjusted headstock bearings, checked tyre pressures but no difference.

My friend's identical K3 doesn't do it so it is a problem with mine.

Any ideas (apart from not letting go of the bars)

[LesterPiglet]

How old and what type are the steering bearings. My stock "balls"  looked ok and were adjusted properly but I was at my wits end trying to sort a weave. I decided to buy new tapers and that fixed it.

[anparkinson]

I think that's the way to go.  That can be my winter project....

[basketcase]

I`ve fitted taper bearings and there was still a slight weave at speeds, I`ve put it down to the tyres. Saying that, I`ve also fitted bar end weights and that has taken out a lot of it.
Just my pennyworth!

[florence]

Are you sure your bearings are adjusted correctly?  When I rebuilt mine, it had terrible steering.  It turned out that I hadn't quite located the top yoke properly.  It looked fine but the bearing kept loosening itself.  The friendly MOT man pointed it out.  We loosened everything a little, tapped it all round with a leather mallet, then tightened everything.  It has been lovely ever since (17yrs).

Incidentally, I fitted new standard bearings and they are perfectly good and easy to put in.  I'm not convinced about taper roller bearings.

Has the bike always been like this or has it developed this habit recently? 

[LesterPiglet]

I agree with Florence over tapers. I still can't get my front end feeling the way it did with the standard bearings. Years ago I remember being warned off them as it was easy to set them too tight/loose.

[z1100r]

 The main cause of this steering shake to violent tank slap is your head bearings. I had it on the Direblade and I've had it on my z1100r. On both bikes it didn't do it unless I let go of the bars but releasing pressure on the bars would set it off and it would become very violent if you didn't grab them again. Both head races were replaced with tapers. Tapers are a doddle to set but you seem to have to keep setting them on a regular basis.

Weaving is usually rear end, knackered shocks/swing arm bushes/wheel bearings/flat or bald tyre.

 IMO Handling problems are never usually just one thing, its just that the first thing sets other things off in some sort of chain reaction.



It does seem weird that it took 30+ years on stock ball bearings before the headstocks started wearing out and playing up, yet I thought I could do better and replaced with taper roller....why did I do that...madness.