FF: Forks Girdraulic eccentric shimming method

Spqreddie

Well Known and Active Forum User
VOC Member
I had a similar problem with the Girdraulics on my Shadow and it was the top link FF4 which had been machined wrong. End faces of the area where the flanged bronze bush FF6 press in were not machined equally central through the axis in relation to where the link attached to the head clip FF1 thus it tried to throw the fork leg sideways at the top. The top link FF4 was not bent or distorted in any way, just machined wrong which was clear when placing another good link on top of the problem one. To correct it I ended up machining new FF6 bush with different thickness flanges which resulted in the forks all aligning up. It took days to realise what was going on and yes the bike had being run with this error for years by the previous owner and probably like that from new.
Indeed Simon,
Probably something similar in some of the bushes or link happening with mine..
 

Albervin

Well Known and Active Forum User
VOC Member
Hello Spqreddie, I am not sure that I understand what has gone wrong. The only shims in the steering parts are those for the eccentrics. There are no other shims on any of the other spindles. If you take the FF33 and insert it into the bottom of the main steering lug then it should just appear in the middle of the hole at the top of the steering lug. Prior to this the FF36 washer and all parts of the lower cup and cone type bearing will have been placed on the FF33. The upper cup bearing, FT128 should be in place. If the top of FF33 is not in the middle of the top cup bearing then that suggests that some part of the lower bearing is not fitted correctly. Lower the FF33 slightly so that the bearings are loose, but don't fall out, and then see if the top of the FF33 tube is in the middle of the top cup bearing. If it is then, to me, that suggests that at least one part of the lower cup and cone is not properly into its housing.
One other thing to be aware of is that the felt washers, to protect the lower cup and cone, are often/always supplied much too thick. Roughly double the thickness needed. Make sure that felt washer is not causing trouble.
Come back with more information after you have tried that.
The current thinking in the land of OZ is that a suitable "O" ring will do the job of the felt washer.
 

Spqreddie

Well Known and Active Forum User
VOC Member
Hello Spqreddie, I am not sure that I understand what has gone wrong. The only shims in the steering parts are those for the eccentrics. There are no other shims on any of the other spindles. If you take the FF33 and insert it into the bottom of the main steering lug then it should just appear in the middle of the hole at the top of the steering lug. Prior to this the FF36 washer and all parts of the lower cup and cone type bearing will have been placed on the FF33. The upper cup bearing, FT128 should be in place. If the top of FF33 is not in the middle of the top cup bearing then that suggests that some part of the lower bearing is not fitted correctly. Lower the FF33 slightly so that the bearings are loose, but don't fall out, and then see if the top of the FF33 tube is in the middle of the top cup bearing. If it is then, to me, that suggests that at least one part of the lower cup and cone is not properly into its housing.
One other thing to be aware of is that the felt washers, to protect the lower cup and cone, are often/always supplied much too thick. Roughly double the thickness needed. Make sure that felt washer is not causing trouble.
Come back with more information after you have tried that.

I have just spent three months of trying to get a steering head/stem working. Totally impossible when the bearing cup housings are totally shagged and shot. This has led to having the the whole system jigged, mandrel set and bored. The upper bearing cup was "floating" and the lower was loctited and off centre. It was either a matter of poor maintenance or a crash. A lot of fine engineering, a shim and sleeve plus some inventiveness were required to bring all into line. There are no short cuts here as it all has to do what it is supposed to. Amazing that I rode it at 90 mph and it felt fine. But in the slow and twisty roads it was horrible. Next will be the rear suspension ....
Dear Norman and Albervin,
Thank you for your tips, and sorry I might have expressed myself not clear enough.
I have not yet assembled the fork into the UFM.

the fork is disconnected from the bike, it is on the bench. I have just inserted the stem into the hole of FF1, and they do not align.
in order to correct it, I had added eccentric spindle shims on the left side to move the assembly to the right to come out more in the center of FF1.

Will send some photos later may be.

thanks!
 

Albervin

Well Known and Active Forum User
VOC Member
Dear Norman and Albervin,
Thank you for your tips, and sorry I might have expressed myself not clear enough.
I have not yet assembled the fork into the UFM.

the fork is disconnected from the bike, it is on the bench. I have just inserted the stem into the hole of FF1, and they do not align.
in order to correct it, I had added eccentric spindle shims on the left side to move the assembly to the right to come out more in the center of FF1.

Will send some photos later may be.

thanks!
I considered pre-assembling the forks before I fitted them to the UFM. But for the same reasons you are now giving I decided to fit the blades etc. after fitting the links. Whether this is correct or not I will soon find out. However, I thought it best that the stem, head, eccentrics and head clip fit before I progress to the other stuff. In hindsight I think that was a good idea. If the blades and other parts do not fit then it will be several stiff drinks and a lot of head scratching. This is all considering I rode the bike three years ago and it (sort of) felt OK.
 

timetraveller

Well Known and Active Forum User
VOC Member
Hi Spqreddie, I agree with Albervin. I would always assemble the steering head first into the UFM and then fit the fork blades. It is much easier. If you still have the cup and cone bearings top and bottom then it is such a pain to assemble it without getting greasy ball bearings all over the floor that you do not need the extra aggravation of fork blade flapping about.
 

Albervin

Well Known and Active Forum User
VOC Member
Precisely. It is quite easy to assemble the steering stem with lots of grease on the bearing cups and balls. No need to get the correct tension as long as there is minimal play. I am trying out the use of an "O" ring instead of felt at the bottom of the stem. Pull up the stem, fit the steering damper and then attack the blades. Gently.. Then fit the hydraulic steering damper supplied by TT. Simple!
 

Spqreddie

Well Known and Active Forum User
VOC Member
Thank you! but if you do this way, you might not spot the issue I am dealing with.
Or may be you can actually forget it, as the blades will just self align and self center..
Need to think about!
Eddie
 

timetraveller

Well Known and Active Forum User
VOC Member
Not really Spqreddie. It is mounting the blades which will tell you whether anything else is out and by how much. But only after the central parts are already there.
 

Bill Thomas

Well Known and Active Forum User
VOC Member
If we are talking about the eccentrics ?,
You know by putting the spindle through and doing it up tight,
The eccentrics are often out of line, Just a few thou ".
 

Spqreddie

Well Known and Active Forum User
VOC Member
Hello all!
I believe I have find a very good compromise for the shimming of the four spindles.
all the individual components move freely with no noticeable play, and the big washers can be just rotated by hand.
All this whitout lubrication. So I am sure this will even be better when oil or grease will be applied.

Trouble is that when inserting the Steering Stem FF33 into the head clip FF1, they are not perfectly concentric! (the steering stem is slightly too on the left so need to force it a bit to the right to get it in the FF1 hole), so this make the hole assembly a bit stiff. It still falls under its on weight so it's not too bad, and probably when lubricated it will be even better, I believe than that I could leave it as it is but still not ideal.

I have shimmed the stem as much as possible to the right and is a bit better, but not sure if this is the solution. Some of the links might be bent? and this is why the stem is not pointing perfectly vertical?
Or it might be vertical but too on the left as some of the bush too thick and moving all the assembly to one side...?

as suggested above, might need to disassemble everything again and get some bars of the right diameter through the eyes and measure everything for straightness.. :-(
Hello! I went to the garage and too a few pictures to try to better explain the situation.
As you can see when all is assembled, the steering stem FF33, is not concentric into FF1 top clip. Despite having shimmed it as much as I could in order to move it to the right and center it, it is still not concentric.
It could go in by slightly force it in. but then the fork doesn't move as free as the single link would move. there is some friction creating somewhere.
I am sure that if I will add oil and grease and use it a wile, it will free up. So eventually i could even use the fork as is, but given it is still all apart this is as well the occasion to correct it.
May be just by correcting the FF5 bushes?
Any other Idea? where is should look?
Thank you!!
Eddie
FF33 and FF1 (1).jpeg
FF33 and FF1 (5).jpeg
FF33 and FF1 (2).jpeg
FF33 and FF1 (6).jpeg
FF33 and FF1 (7).jpg
 
Top