Steering bearing what torque to use

[vaclove]

I went through the long thread of Steering bearing and clonking forks issues. There have been lot of information and advices. Maybe too many to pick the best.
I suffer from the well described symptom of hard clonk when going over a pothole in low speed. Dont really know if it is the bearing or fork. Also I am not sure if to resolve it with dealer or myselft.
According to the BMW repair manual, they describe how to tighten the steering head bearing, if there is a play - I thought might be easy enough to try.
They describe:
Tighten to 25nm, move the handlebars 3xtimes complete arc, then losen by 60° and retighten to 10nm.
One member of this forum metioned the BMW torques are too low in this instance and that he tightens is more. Does anybody know how much more would be adviceable? Or did the "clonking" ruin the bearings already?

Many thanks for your opinions

Vaclav

 

[Greggers]

Vac ...

That procedure sounds about right, but the forks can be 'internally' clunky too.
Check the bearing for play before doing anything else otherwise you'll potentially be creating a poblem to fix ...

G

 

[vaclove]

Fatso procedure negative

Greggers,
thanks for the reply. I have used the Fat assistant procedure you have described earlier. The head bearing seems absolutely fine, handlebars move easily from side to side and there is no play whatsoever.
The clunkiness seem to come from the forks itself. When I use the front brake and move the bike back and forth, the forks make sort of clunky sound, they did not make before.
Could you advice what that is it/how to fix it?

V

 

[Dave Ett]

Only time I've had clunky forks is when the internal bushes had worn out on my FJ1100. How many miles has your bike done? If its less than 50,000 I'd be very disappointed if the bushes had worn sufficiently to clonk.

 

[vaclove]

Bike has only 14000

Well, it is my first bike, so can't really compare it with anything else. The forks feel normal at higher speeds, but at slower, I feel they dont absorb the impacts as smoothly as thy used to. They dont leak or anything, just suddently started to feel diferent.
As there is long history of clunking suspension on this forum, I am sure someone experienced similar behavior.

 

[v8legend]

If you're really not sure what it is, then get someone to check it straight away. It could be nothing, it could be normal. On the other hand, it could be catastrophic.

Surely someone nearby could help. Check your local region section.

 

[Greggers]

Vac ...

You've checked the obvious thing, if the steering head bearing's ok then there's no need to disassemble 'just for a look' - wear or mis-adjustment is very obvious so if they're you'd have felt it. As long as the forks have a smooth action, no obvious odd noises or graunching, then I think you'll be ok.

With the standard internals there's a spacer inside the spring at the top of the forks which can sometimes be responsible for the noise - if it's displaced then the spring can move on it so if it's compressed enough then sometimes it will shift and make the clack or clunk ... If you look at the last picture in the link below you'll see it (just) inside the spring under the fork-top cap.

You said they started to feel different at low speed - can you describe that a little more?

I fitted a set of BiTubo cartridge inserts a year or so ago - they made a massive difference to way the bike feels on the road, smoothed out the ride and improved handling.

Greg

 

[vaclove]

Different feeling at low speeds

Greg,
At some ocations, when I ride over a bump or pothole, I notice harder impact in the handlebars that I used to notice before. Something like suspension would not absorb the impact that well. I do not really hear any clunking, but sort of feel the clunk in my hands. Maybe something like the front wheel would jump to the air a bit.
Could it be that the oil in the forks got old?
When I go with the bike from edge of a pavement, suspension works fine and smooth. When I ride straight, stand up and swing on the forks, I also do not notice any abnormalities.
As I plan over 2000m Eurotrip in near future, it would be great being able to diagnose this problem, so I can manage fixing it.

Many thanks for your help.

 

[sigmaglide]

forks

Vac . just a thought it might be the floating front discs there is a lot of movment in them. and you might think its from the forks. my discs clunk a little.

 

[Greggers]

Vac...

The forks fitted to the GS are pretty simple - despite being USD they have no adjustment at all.

When I installed my Bitubos I recall the most significant difference was the quality of the ride - it was almost as though someone had planed the rough surface of the road off, all the little jiggles and trembles it had before just disappeared - the rest was fine, firmer springs but just more controlled damping.

How many miles have you ridden the bike for? Could it just be something that you're becoming more aware of as you get more of a 'feel' for the bike?

For the suspension characteristics to change as much as you suggest (and it sounds like the fork is underdamped) then I think you'd have had to have lost a lot of oil, and would certainly have noticed it before now.

If you have to though, it's no big deal stripping the forks ... You've got a manual I guess, but I could help with the Bitubo instructions which - for an Italian firm - were brilliant!

G

 

[vaclove]

So probably is the brakes

I've visited the dealer this weekend and asked them to have a quick look on it. They confirmed it is not the steerring head bearing.
They suggest it is the play in the brakes or something.
Maybe it was bit of placebo effect, but I was bit more calmed down on the way back. I weent through some byways to check the suspension and everything seems ok, so probably I have just been noticind something that was there before.

Many thanks once again for valuable advices, I really appreciate it.

Vaclav