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Old 05-01-2013, 06:43 PM   #811
ontic
 
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The listed amount of oil is a measure the air gap down from the top affair rather than a volume poured in, so with shortened forks we need to make a decision to measure down the same as recommended for long forks (and have a larger air to oil ratio), or to add a little oil volume and eat into the air damper...
I can't remember what I put in mine, closer to 650mm maybe?
Either way it is to some degree a 'tunable' thing.

Richard, what triple clamps do you have there?
Are your forks shortened too? Can we assume you've been through the forks to pull them apart and clean them? My first set of forks had terrible stiction at first- then I pulled them apart and along with a horrible oil/water/dirt emulsion in one fork they were both packed with dirt and gunk,


cleaning that up helped a lot. Then I didn't have the right wheel spacers so when I torqured down the axle it was pulling the bottom of the forks together a bit. With the right wheel spacers in and in their proper places the stiction was reduced again. If the forks are cleaned and have new seals you might want to make sure this is not happening to you. Does that make sense?
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Old 05-02-2013, 11:00 AM   #812
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Hi!

Quote:
Originally Posted by ontic View Post
The listed amount of oil is a measure the air gap down from the top affair rather than a volume poured in, so with shortened forks we need to make a decision to measure down the same as recommended for long forks (and have a larger air to oil ratio), or to add a little oil volume and eat into the air damper...
I can't remember what I put in mine, closer to 650mm maybe?
So, when the fork is uncompressed, the oil level is 650mm under the top of the inner tube? Did I get that right?
The WP-manual shows how to remove the oil from the compressed fork from the top of the inner tube using a plastic bottle. It says " Adjust T137S on level." But which level do they use? There is no more information about this point. Only a little picture.
Quote:
Richard, what triple clamps do you have there?
I don't know who manufactured them, they are not from HPN or Gletter or SWT-Sports (3 german sources for clamps), I bought them at ebay. There are no numbers or signs printed on them. I guess, I will have trouble to legalize them in Germany, but thats another problem.
They are quite heavy, 1,2kg (double of the original ones) and they are made for the GS and fit very well.
click for bigger size:


The forks are also shortened with the little plastic tube in the damper. Also I took them completly apart and cleaned them (they looked similar to yours)

Quote:
Then I didn't have the right wheel spacers so when I torqured down the axle it was pulling the bottom of the forks together a bit. With the right wheel spacers in and in their proper places the stiction was reduced again. If the forks are cleaned and have new seals you might want to make sure this is not happening to you. Does that make sense?
Yes, it does. This was what I meant with "classical reasons". I've had a lot of problems with stiction at my R50/5-forks a few years ago (until I bought completely new ones for a lot of money. I crashed them last year at the north cape, but thats another story ), so I think I know what to look at. The spacers at the WP forks are at the correct place, when I torque down the axis, the stiction is still OK until I screw in the caps at the top of the fork.

I'll have a look at the oil level now, I'm pretty sure thats the reason for the stiction.

Regards,
Richard
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Old 05-02-2013, 11:20 AM   #813
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Quote:
Originally Posted by Sauerkrautman View Post
So, when the fork is uncompressed, the oil level is 650mm under the top of the inner tube? Did I get that right?
No sorry, I typed it wrong, I actually meant 650ml (millilitres) is around what volume I may have put in. We are supposed to measure down from the top but I haven't gotten around to that yet.

I can't think of much else for your stiction, you seem to be covering the bases...
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Old 05-02-2013, 11:49 AM   #814
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Quote:
Originally Posted by Sauerkrautman View Post
Hi!


So, when the fork is uncompressed, the oil level is 650mm under the top of the inner tube? Did I get that right?

The spacers at the WP forks are at the correct place, when I torque down the axis, the stiction is still OK until I screw in the caps at the top of the fork.

I'll have a look at the oil level now, I'm pretty sure thats the reason for the stiction.

Regards,
Richard
The oil level is used to give the fork a bigger or smaller air chamber above the oil.
The size of that chamber makes the air pressure rise sooner or later when the fork is compressed.
That air pressure is used to help the spring when its not strong enough to keep the fork from bottoming.
How big that chamber needs to be depends on what spring strength is used, rider weight, bike weight and how it is set-up.

I really doubt the oil level is causing the stiction. If the air chamber is to big it might be a lack of lubrication because things are dry inside. But than you would not have a working damping system.

The oil level should be measured when the fork is compressed without the springs and pre-load spacers.

When you say the stiction gets worse when the caps are screwed in it might be that your springs are to thick.
When the springs are compressed there outside diameter might get bigger. Than they could get stuck in the fork and cause stiction. The springs should be about 1 mm thinner than the tubes inside diam.

I hope this bla bla bla might help. Good luck.
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Old 05-02-2013, 12:01 PM   #815
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Quote:
Originally Posted by Sauerkrautman View Post
Hi!


I don't know who manufactured them, they are not from HPN or Gletter or SWT-Sports (3 german sources for clamps), I bought them at ebay. There are no numbers or signs printed on them. I guess, I will have trouble to legalize them in Germany, but thats another problem.
They are quite heavy, 1,2kg (double of the original ones) and they are made for the GS and fit very well.
click for bigger size:

Those look like R-Dubb clamps!

EDIT: I Lied, they now look more like HPN clamps.

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Old 05-02-2013, 12:57 PM   #816
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very quick question for everyone's feedback. I'm looking at a 100 PD with the aluminum rear swring arm that has an Ohlins in the rear. I only know about the old steel swing arms from my old R80GS.

I'm super tall with long legs (6'5) and I also have some of the many concerns about the low height of the 100s. I have a KTM dirtbike and keep it fairly tall by design. For this 100 I'm going to orient it and use it much for for off road. I'm really hoping it can potentially hang versus a KTM 950 (possibly a tall order?). So I don't mind it tall in fact I prefer it. I don't care too much about street handling as long as its halfway decent.

can I jack up the aluminum swing arm a lot to get good high clearance? Similar to the photos on the first page for example (photo 1, photo 2? Which fork is also recommended? I don't mind rebuilding / repringing. I'd actually love a 48mm from a KTM dirt bike if possible rather than trying to find a hard to find 50mm

thoughts?
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Old 05-02-2013, 01:18 PM   #817
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Quote:
Originally Posted by dieselcruiserhead View Post
very quick question for everyone's feedback. I'm looking at a 100 PD with the aluminum rear swring arm that has an Ohlins in the rear. Can I jack up the aluminum swing arm a lot to get good high clearance?
Short answer, not recommended and/or difficult+expensive. Ujoint issues make up most of the problem, so you can't simply stick a bigger shock in there or mount it differently. The only other option would be to install a longer swingarm from HPN, but that's very very expensive. However, I'm curious about the feasibility of getting a longer shock with more travel (as I'm told was possible with my recent shock order) and using the engine raising kit from MaxBMW to assuage the resulting ujoint binding issues. But that's a topic for another thread...

Quote:
Originally Posted by dieselcruiserhead View Post
I'd actually love a 48mm from a KTM dirt bike if possible rather than trying to find a hard to find 50mm

thoughts?
I'm currently going this direction as well. They're easier to find, and still being installed on current lines of KTM bikes. There's another thread for this particular unholy union fyi. I'll be posting some more details there when I get the parts.
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Old 05-02-2013, 03:55 PM   #818
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Hi again,
Quote:
Originally Posted by Stagehand View Post
EDIT: I Lied, they now look more like HPN clamps.
yes, they are similar to the HPN clamps, but not identical. They are more like the Gletter clamps, but also not identical (the size is different, I think). Now I'm thinking, they are self made, with the gletter clamps in mind.

I have now 650ml oil in each fork-leg. Its now at the level of the underside of the springs (I hope, it's understandable).
With the springs removed, the forks move smooth again.
With the springs back again and pushing the legs upside, there doesn't seem to be much stiction. But with the bike back at its wheels, the stiction was there.
I shortened the springs, maybe they are bending now, causing the forks to stick. But it doesn't feel so.
The outer diameter of the springs is small enough, they are the original springs.

However, it seems to be slightly better now. Maybe the parts have to break in again, after I cleaned them? I know that I rotated the slide parts of the forks while cleaning them, so they have a new position now.
I'll put the stuff together and ride some bavarian gravel roads to get the fork forking again.

@dieselcruiserhead:
I've seen some people putting the swing arm of the R1150GS into the airheads. I saw even one version of this without changing the frame for the shock (it was at a local tuner here in South-Germany, but he wasn't impressed by my idea of the WP 50 forks ).
At the german "2-ventiler" (airhead)-forum is one really tall guy who built his GS into a real Enduro-machine, he also sells his tuning-work. His websites are only in german, but I'm sure you can ask him anything, if you want:
http://swt-sports.de/ and http://enduroboxer.blogspot.de/

Here are some photos of his machine:
https://plus.google.com/101621162510...sts?banner=pwa
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Old 05-02-2013, 06:05 PM   #819
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I was in a similar position to you with my YZF KYB fork conversion. Newly rebuilt forks. I also put the stiction issues initially down to breaking in new parts. In the short time I ran it likely this it ruined the fork bushes, which was truely annoying.

I eventually found that the prior owner of the forks had beaten the axles into place at some stage. This slightly peened the end of the axle over on the head, so that the axles didn't seat properly in the fork. As a result the forks didn't align properly when the wheel & axles were bolted up, and though the forks were fine off the bike, there was huge stiction when the forks were all bolted up. I noted that the stiction didn't occur until I tried to tighten the axle, i.e. when loose the forks were fine. Eventually I discovered what the issue was & ground the axles back into shape. The movement in the axle seating properly was small - probably only 1mm.

It sounds like you have a similar issue to me. Check that the axle / spacers / bearings etc are all mounting properly. Maybe not a fork issue at all.
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Old 05-02-2013, 09:47 PM   #820
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Hey Richard,
the 650ml was just off the top of my head, I think I remember it as being well over half a liter of oil but it has been a while- I could be wrong, and either way I was just guessing with mine, best bet will be to measure the air chamber.
here is a thread that mentions the air chamber and the guy Moto520 who is quoted in it is from KTMtalk and seems to know his stuff with these forks,
http://www.husaberg.org/forum/viewtopic.php?f=8&t=4820
short story with these forks un-shortened (on KTM's) the air chamber is recommended by these users (not the manual, don't know what that recommends) to be around 225-230mm. So pull the springs out, compress the forks and measure down.
I suspect as a baseline because we have shortened fork travel we should be proportionately shortening the air gap, but that is a complete guess on my part- either way it is tunable to personal tastes.

I agree with the others, so long as you have a bit of oil in there I don't see how having a bit too little would create your stiction.
Your seals aren't dry are they?

My thoughts are Boxa'a'bits is probably on the money and that this might not be a fork issue per se-
The triple clamp offers a big unknown to me as if it might be a home made one-off type of thing it might be a fraction out somewhere. They look beefy and well made so hopefully we can assume all the bores are straight/parallel.
My suspicion is the fork tube centre to centre measurement is a bit out and the the bottoms of the fork are being pulled in or pushed out a bit.
you say
Quote:
The spacers at the WP forks are at the correct place, when I torque down the axis, the stiction is still OK until I screw in the caps at the top of the fork.
Can you try the opposite, screw down the caps without the axle/wheel on and see if you can notice any of this stiction? Not an easy task, I know.

When you screw the cap on the fork the cap centres the top of the damper rod- if the bottom of the forks are being pulled or pushed out of parallel a little it might be this final centering of the damper rod that makes the stiction appear- whereas previously without the cap on and with the damper rod free to shift out of centre it might have moved freely.
I just took the caps off and had a quick look at my spare set of WP50's to see if I can think of anything else...

At this point, rather than just running it and seeing if it improves, I would probably consider doing a proper pull down of the forks again just to check everything is right, look for signs of the problems and double check something hasn't gone wrong in your re-assembly. Even if you don't notice anything wrong, just pulling it apart and putting it back together, regreasing seals, etc, etc, might solve it

if it is an axle/wheel spacing issue, that might be a little harder to figure out. Given your experience with "the classical reasons" already it seems unlikely that you would not notice the fork bottoms being pulled or pushed in a bit, or tweaked from out of parallel into parallel...

given the price of full rebuild kits for these forks (the only way I know of so far to get new forks bushes) I would hate to ruin my bushes or something else if I could avoid it- like Box'a'bits seems to have done.
It sounds like you have serious stiction so something is definitely not right in my opinion.

And sorry for the long blah blah post, hopefully all this talk will help get to the solution.


Good luck.
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Old 05-03-2013, 12:27 PM   #821
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thank you guys for your info... appreciated..
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Old 05-03-2013, 01:03 PM   #822
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Quote:
Originally Posted by Stagehand View Post
EDIT: I Lied, they now look more like HPN clamps.

They look like mine. If they have 3 screws at the leg clamps, they are of the type that BoxerSupplies sell. He may have ABE papers for them.

J
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Old 05-04-2013, 05:15 PM   #823
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Eek

Quote:
Originally Posted by Box'a'bits View Post
I was in a similar position to you with my YZF KYB fork conversion. Newly rebuilt forks. I also put the stiction issues initially down to breaking in new parts. In the short time I ran it likely this it ruined the fork bushes, which was truely annoying.
That doesn't sound very good.
I have a question about your conversion: (I haven't read your complete thread, so don't get mad when the anser is in there) Did it work out using the BMW mastercylinder instead of the 11mm of the YZ250F?
I wasn't so sure about that and used the KTM mastercylinder, but since I haven't driven the GS since the conversion, I don't know how it works with the heavy GS instead of the KTM. I really would like to use the original master cylinder again...
And another question: Which outer diameter do the upper tubes have of your forks?

Quote:
I eventually found that the prior owner of the forks had beaten the axles into place at some stage. This slightly peened the end of the axle over on the head, so that the axles didn't seat properly in the fork.
That was exactly the problem I had with my /5-forks. I searched some months for it and i found out what it was, after I bought the new forks.

So today I checked again if the stiction of the WP-forks gets any less if I loosen the screws or the axle itself. The axle slides with not much pressure through the fork, everything as it should be. I even used another axle, but nothing changed.

Quote:
Originally Posted by ontic View Post
The triple clamp offers a big unknown to me as if it might be a home made one-off type of thing it might be a fraction out somewhere. They look beefy and well made so hopefully we can assume all the bores are straight/parallel.
My suspicion is the fork tube centre to centre measurement is a bit out and the the bottoms of the fork are being pulled in or pushed out a bit.
you say
This is something I'll try to measure (but for that I need to tear down the complete forks).

Quote:
Can you try the opposite, screw down the caps without the axle/wheel on and see if you can notice any of this stiction? Not an easy task, I know.
Yes, I tried that and yes, there is some stiction, but I don't know if that is the same amount I feel when everything is complete and the bike on its wheels.
But with the load of the bike the stiction might just increase because the load is not in the axis of the fork.
So I took out the legs of the fork and searched for this little amount of stiction.

First a little photo:


D is the damper. If I move it in direction 1 there is no stiction at all.
O is the outer tube. When I move it a little bit up and down (2 in the picture, maybe 1mm) it moves also without any stiction. But if I move it more than 1mm, there is the stiction again. Notice that I took out the upper seal of the measuring. The second seal comes only out when I take the whole fork apart, which I'll do tomorrow.

So I think, it might be the bushes of the outer tube.
So if they are the reason, I might try to break them in again, and if it don't work I try to get some new ones...

Quote:
Originally Posted by redboots View Post
They look like mine. If they have 3 screws at the leg clamps, they are of the type that BoxerSupplies sell. He may have ABE papers for them.
Too bad that my clamps have only 2 screws per side, so they cannot be the boxersupplies clamps. But thanks for the help!

Regards,
Richard
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Old 05-04-2013, 06:11 PM   #824
Box'a'bits
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Quote:
Originally Posted by Sauerkrautman View Post
That doesn't sound very good.
I have a question about your conversion: (I haven't read your complete thread, so don't get mad when the anser is in there) Did it work out using the BMW mastercylinder instead of the 11mm of the YZ250F?
I wasn't so sure about that and used the KTM mastercylinder, but since I haven't driven the GS since the conversion, I don't know how it works with the heavy GS instead of the KTM. I really would like to use the original master cylinder again...
And another question: Which outer diameter do the upper tubes have of your forks?
The 13 mm master cylinder isn't an ideal ratio mix with the 2x27mm nissin caliper. However I wanted to retain the stock master cylinder (because it was going to be an issue replacing indicator switching). With the 320mm disc it is acceptable. It would work better if I sleeved the M/C down to 11 or 12 mm. It helped when I got the rear brake working more effectively.

For perspective, the brakes are definitely an improvement on the (unmaintained) stock system the bike came with.

- 56.8mm top fork clamp, measured on the fork legs
- 59.15mm bottom clamp, measured on the fork legs.
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Old 05-04-2013, 07:36 PM   #825
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Quote:
Originally Posted by Sauerkrautman View Post
D is the damper. If I move it in direction 1 there is no stiction at all.
O is the outer tube. When I move it a little bit up and down (2 in the picture, maybe 1mm) it moves also without any stiction. But if I move it more than 1mm, there is the stiction again. Notice that I took out the upper seal of the measuring. The second seal comes only out when I take the whole fork apart, which I'll do tomorrow.

So I think, it might be the bushes of the outer tube.
So if they are the reason, I might try to break them in again, and if it don't work I try to get some new ones...
Sounds like you are getting somewhere. Are both forks doing the same thing?
I have my spare forks in that same state in the vice at the moment so I had a little look and there is no stiction like you are describing. The only stiction-like thing that happens is right at the bottom of the tube travel where the bottom of the tube goes over the hydraulic stop- it kinda suctions and sticks there but the rest of the travel is smooth and free (only remnants of oil are in these forks though).

Did you download the Husaberg manual?

two bushes of potential issues.




Did you already put new bushes in or are these old ones?
If you find a supplier for only the bushings I'd love to hear about it.

Also, I've used the KTM master cylinder and caliper as a matched pair and with the 320mm rotor the brakes are excellent. I've only tested on road so far. A decent little grab will very easily lock up my front knobby tyre up on the bitumen- worlds better than the stock G/S brake... I wouldn't want much bigger brakes.
But then choosing to keep the KTM master cylinder was the start of some scope creep- new throttle, new switchgear and new clutch lever, etc.
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