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Old 05-11-2013, 10:24 AM   #826
Sauerkrautman
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Eek

Hi,

it's me again. I did a lot of stuff the last days, so now the update:

At first, I took the complete forks apart to take a look at the bushes.
As I thought, rotating the bushes helped a lot to reduce the stiction.
So I rotated the parts until everything went nice and smooth. Now the outer tube without the inner parts (the damper and the spring) and without the oil seal just fell down without any stiction and or friction.
The same after I connected the outer tubes with the axle and without tightening the clamps for the axle.
After I tightened the clamps there was a tiny little bit of stiction. But note: the axle is not bend and it goes through the holes without any problems.
The stiction ist the same, no matter where I push the tubes with the axle (if to the upper end or the lower end). If the tubes were bend or not correctly aligned, I would have expected a different stiction at the upper and the lower end of the forks.
With the wheel it was the same.

After I put the damper without the springs in, the amount of stiction didn't change.
With the springs it is nearly impossible to measure the amount of stiction.

But after I put the bike back a its wheels, my old friend "the stiction" was there again.
This was still without the oil seals. The stiction is now much better, but still too much to enjoy riding with these forks.

After I put everything back together, I rode some kilometers (170) to run in the forks. Of course nothing did change, but I'm sure you knew that before...



I also made a video to compare the GS forks with my WP forks:
youtube-video

In the video it doesn't look as bad as it is,but on some roads the forks didn't move at all.
The damping is completly "open" and still the forks feel way to hard.

But beneath the stiction and on good roads, it feels not bad running with the WP forks. The bike reacts instantly and there is no shimmy at higher speeds. The brake works, but the original one with a 320mm disc works better. The shortened springs seem to be not stiff enough, but I expected that.

Quote:
Originally Posted by ontic View Post
Sounds like you are getting somewhere. Are both forks doing the same thing?
yes, they did.
Quote:
Did you download the Husaberg manual?
yes, i read that, but I didn't find any information to help me in this situation.
Quote:
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.
I don't have new bushes, maybe they are just worn out?
I'll ask my KTM-dealer next week.

Until that I'll take the forks apart, again. It's so much fun...

Regards,
Richard.
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Old 05-11-2013, 02:35 PM   #827
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When you tighten the axle, are the forks extended or compressed. ? My suspension guy always pushes up and down on the forks to align things as the forks compress before tightening the axle. It is usually more crucial in USD forks as any slight twist will result in "sticky forks" if there is even a slight bend in a fork tube, the effect will be the forks will be splaying in or out as they compress. Each fork by themselves would feel fine but the result of both together clamped up won't be. I have even seen top and bottom clamps that aren't even perfectly aligned.
After watching the video again, I am wondering if what you feel as stiction is actually stiffer damping than you are used to. The GS fork has a weird compression damping system which is a tapered rod setup so that it changes the oil flow as the fork compresses. So the initial damping is VERY light, almost non existant and it moves very freely over small rocks and bumps. But it falls down under big impacts like litting big rocks and ledges where its suddenly asked to compress and cant flow enough oil quickly enough so it jars badly. With the nornal cartridge design the shim stacks take care of the oil flow and can stand big impacts better, when set up properly. Maybe you will need to lighten up on the compression damping by having the shim stack altered.

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Old 05-11-2013, 07:24 PM   #828
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Hi Richard,
this sounds really frustrating.

A few quick basic questions-

How were your dust and oil seals? new, old?
New original blue oil seals sold here by the way (I grabbed a few sets a while ago when I had a box coming over from Germany).

How did your bushings look? it could be that they are too worn and causing/contributing to stiction by allowing the damper rod to go off center...?
The 'full' rebuild kit for these forks is part number R904. It would be great if we could just source individual bushings though.
(there is a description here of what is and isn't in this kit).
I've been meaning to buy one of those kits for a while... if anyone wants to try to negotiate two (or more) kits for cheap price (and then post a kit to me) I'll be in for a kit.
unfortunately Australia is not the ideal place to sort this kind of stuff.

Also, what weight oil are you using in your forks?

You don't happen to have any friends or acquaintances nearby who have done this already and/or might have a different set of known good triples/axle you could try do you? I am trying to think how to isolate problems between the forks and the clamping geometry.

I'm not sure what I suspect most. After some googling, worn bushings seems a likely potential cause for (some of) your symptoms. Whatever the main cause, there might be a bunch of contributing factors as well to complicate things.


P.S. for everyone using these forks- I think we are going to have to try to figure out solutions to the 'rebuild kit' problem for these forks. While the R904 kit is still listed on some sites (and is expensive), most parts places don't seem to stock it anymore and there doesn't ever seem to have been an aftermarket source for kits or parts. If anyone gets a chance to talk to a KTM parts place in person it might be worth trying to find out the longer term availability of this kit and any possible sources for individual components (especially bushings).
Thoughts?
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Old 05-12-2013, 05:35 AM   #829
Sauerkrautman
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Bluhduh

Hi!

Quote:
Originally Posted by Phreaky Phil View Post
When you tighten the axle, are the forks extended or compressed. ? My suspension guy always pushes up and down on the forks to align things as the forks compress before tightening the axle.
Yeah, I did that too, there is no difference between tightening the axle when the forks are compressed or extended.

Quote:
After watching the video again, I am wondering if what you feel as stiction is actually stiffer damping than you are used to.
I was wondering that too, but it is definitly not the damping, since it also happens without any oil. Also there is this typical behavior of stiction: When I try to compress the fork slowly nothing happens until I apply more force. Then the forks "jump" to the new place and stay there when I let the forks slowly go. There is a difference of up to 5cm between having the forks compressed or when I pulled them before (I hope, I've written it right, I'm still learning to use the english language for technical purposes).

Thanks for the information about the GS-forks.
Compared to my WP-forks they have nearly no stiction at all, although people often say that it has too much stiction...


Quote:
Originally Posted by ontic View Post
How were your dust and oil seals? new, old?
The dust seals are the old ones and the oil seals are new.
My oil seals are black, but I buyed them at the KTM dealer, so I think they should be ok.
And since the stiction is also there without the seals I think they are not the reason. Although they add some stiction to the forks, but I think, it is, compared to the "real" stiction not much.
Quote:
How did your bushings look? it could be that they are too worn and causing/contributing to stiction by allowing the damper rod to go off center...?
I took photos, as I took the right fork leg apart (click for bigger size):
the lower bushing:
outside:


inside:


the upper bushing:
outside:


inside:


As you can see, there is only one little damaged part at the lower bushing, I'm not sure if this could cause the stiction.

The tubes of the fork leg look very good, there is absolutly no sign of wear at the areas where the bushes glide.
I measured the upper tube, it is a little bit bend, maybe 5/100mm or even less. I did hold it against a glas plate, so I can not measure the exact value.

Quote:
The 'full' rebuild kit for these forks is part number R904. It would be great if we could just source individual bushings though.
I found a dealer in Austria who has the bushings, maybe I'll order some, but they are is quite expensive:
Enduroklassiker.com
The lower bushings of the marzocchi shiver 50 may fit, since they have the same dimensions: 50.70x20x1.0
Here someone sells the bushings (sorry, link only in german).
ebay-link

The upper ones are too thick (2,5mm instead of 2mm), so they won't fit.

Quote:
Also, what weight oil are you using in your forks?
I use SAE 5W from Wilbers.

Quote:
You don't happen to have any friends or acquaintances nearby who have done this already and/or might have a different set of known good triples/axle you could try do you? I am trying to think how to isolate problems between the forks and the clamping geometry.
I tried a different axle, but nothing did change.
Unfortunaly I don't know anyone nearby who has the WP Extreme forks. A friend used to drive a KTM LC4 400 with them, but he sold it. He tries to buy it back, since he loved the bike, but I'm sure he won't ge this bike back until the end of the year.

Quote:
If anyone gets a chance to talk to a KTM parts place in person it might be worth trying to find out the longer term availability of this kit and any possible sources for individual components (especially bushings).
Thoughts?
I'll ask my KTM dealer tomorrow, maybe he has some information.

Regards,
Richard
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Old 05-12-2013, 02:43 PM   #830
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Stem Problems again.....

Had a good weekend getting certified to teach Ultimate bike bonding through MSF. After turning the handlebars back and forth for 3 days straight, I figured I should check my head bearings. This is what I find.....



 photo EC9A6631-1500-4DF6-8E90-5E214A5AD523-4370-000007FE0E19675F_zps31643b27.jpg


REally fucking pissed off as I 've spent a lot of time and money on this stem. If you remember it was to thick to allow the bearings to seat and I had to pay again to have in turned down.

QUESTION: What is the quickest and best option. Can I have it pressed out and press in a BMW stem or are they too short?? Guy is a busy guy, and I need it asap. Let it be a lesson.
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Old 05-12-2013, 02:45 PM   #831
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Old 05-12-2013, 03:03 PM   #832
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Quote:
Originally Posted by hardwaregrrl View Post


REally fucking pissed off as I 've spent a lot of time and money on this stem. If you remember it was to thick to allow the bearings to seat and I had to pay again to have in turned down.

QUESTION: What is the quickest and best option. Can I have it pressed out and press in a BMW stem or are they too short?? Guy is a busy guy, and I need it asap. Let it be a lesson.
Balls. How much torque are you puting on that thing? It shouldn't get much - just enough to preload the bearing a bit. These guys make steel stems for fitting KTM forks on BMWs. See if they can help: http://www.roemerteam.de/inhalte/bmw...zialteile.html
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Old 05-12-2013, 04:44 PM   #833
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Damn Jenna, that sucks.
IF you end up putting another of the same stem back in (which seems unlikely), could I suggest trying to get some longer blind nuts to use a bit more of the available thread in that stem? Also, others who are running this set up might want to take note.

Originally I was planning on making a bunch more of these steel ones up (out of the swing arm bolt things), plating them, and sending them over to Solo to pass around but my TIG welder died and I haven't been able to get it fixed or get a new one yet. They are very easy to make, and could even be done with a stick welder or gasless MIG (and some grinding and cleaning).
The old longer thread aluminium one doesn't feel quite as much of an improvement as the steel one I made does (I do not like the feel of aluminium threading into aluminium), but it is still a vast improvement, so sourcing one of them would be good as well.

here is my old post regarding them

Quote:
Originally Posted by ontic View Post
from left to right is, the old KTM aluminium blind nut with the long thread, the new KTM aluminium blind nut with very little thread, the steel blind nut I made with maximum thread that will work in the stem (pretty much exactly the same as the nut on the far left), last to the right another of the swing arm things I made the nut out of.


new long thread steel nut vs new short thread aluminium nut- the washer on the steel nut is aluminium and is from the old KTM aluminium nut I have.






Quote:
Originally Posted by Airhead Wrangler View Post
Balls. How much torque are you puting on that thing? It shouldn't get much - just enough to preload the bearing a bit.
I put around 25 ft lb on it before it felt right with the correct bar fall away- I played around a lot, 20-30 is my best guess of where the 'correct' torque is, and to me it did not feel good at all putting that much torque on the newer short thread blind nut (that came with these triples)- really felt like the threads were deforming to me (and thus would over time result in exactly what Jenna has experienced). The thread on those new blind nuts seems ridiculously short to me.
With the longer thread nuts (steel or alu) you can easily give it a bit too much torque (too stiff steering) and it still doesn't feel like it is damaging the threads.

The problem of torque of course is what we covered many pages back- the stem and nut are designed for a smaller contact angle KTM style bearing which needs less torque than the BMW style greater contact angle bearings we are using. Particularly with the short thread nut that most people probably have, and maybe even with a long thread nut, we are probably just asking too much from this stem/design. IMO of course.
In retrospect I would have been much happier with a male threaded stem too- even a steel one at that.
A BMW one aint long enough IIRC,
my YZ/WR triples have a beautiful stem of the more traditional male threaded crown nut under and locking nut over design, but it is too long (like most dirt bike stems will be...)- in the hands of a turner and some careful work it might be adaptable though... I just had a look and it gets a bit complicated. With a good candidate stem in hand you'd really need to sit down with your machinist and just come up with a solution.
It would be nice to be able to start from another available stem rather than having it custom made from the start as I fear the price of someone trying to make a custom stem for a custom triple...

Good luck Jenna, let us know if you want some further pontification...
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Old 05-12-2013, 04:51 PM   #834
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Ok, so briefly......the KTM stem was NOT machined down enough to allow the top bearing to fully seat into the race, thus having to put an awful lot of torque on the little aluminum bolt. Per Hans, I had a steel bolt made....bad idea. A steel bolt into an aluminum stem was not good for buisness .....and that is the result.

I'm wondering if I could drill it out and put a time sert in.....or......I have the KTM stem from the WP50's that I could press out and turn down locally. NOt sure which direction to go at this time. I don't have 2 weeks to fuck around with farming out of state let alone country. Wish I could AW.... I ride this thing pretty hard, but I didn't think hard enough to strip threads.

@Jason....come hell or high water I'll make it to the RR'13. I've got Russian Jew ingenuity on my side.

Anybody have the part number for the aluminum bolt that Guy sent us??

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Old 05-12-2013, 05:32 PM   #835
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Quote:
Originally Posted by hardwaregrrl View Post
Ok, so briefly......the bottom of the KTM stem was NOT machined down enough to allow the bottom bearing to fully seat into the race, thus having to put an awful lot of torque on the little aluminum bolt. Per Hans, I had a steel bolt made....bad idea. A steel bolt into an aluminum stem was not good for buisness .....and that is the result.
Sorry I don't mean to argue especially as you are in a shit of a situation, but I beg to differ on that mate. Steel to aluminium thread might not be the best thing in the world but so long as galvanic corrosion isn't happening and anti-seize is used it sure as hell beats aluminium to aluminium thread- especially such a short threaded section as we started off with. (our engines are held together by steel to aluminium threads- my lovely YZ/WR stem is alu with steel nuts, etc)
How long was your steel blind nut you had made? The reason I ask is because it doesn't look like it was nearly as long as it could/should have been- your stem thread looks stripped only half way down- with my long thread blind nuts (both steel and alu) my stem would have to be stripped all the way to the bottom of the thread for it to strip at all-

I prefer the feel of the steel nut over the aluminium one but that is beside the point- the real purpose wether using a DIY steel one or the older style aluminium one was to lengthen the threaded section on the blind nut so that the thread went all the way down and used every bit of available thread in the stem- that is the real advantage regardless of what metal the blind nut is made of- it shares the greater torque/load required for our bearings over a lot more thread/metal.

some numbers- the short thread alu blind nut has a 8mm section of thread. The older style long thread alu blind nut has a 20mm section of thread. My steel blind nut (still in the bike) from memory was longer and probably 22-25mm (at least) section of thread. I did it exactly as long as was possible before the nut bottomed out.
Very big difference in the load failure and stripping between 8mm and 25mm of thread.

Quote:
I'm wondering if I could drill it out and put a time sert in.....or......I have the KTM stem from the WP50's that I could press out and turn down locally. NOt sure which direction to go at this time. I don't have 2 weeks to fuck around with farming out of state let alone country. Wish I could AW.... I ride this thing pretty hard, but I didn't think hard enough to strip threads.

After thinking and looking at my spare KTM stem for a while, the easiest, cheapest and best solution I can think of might be to to simply get the internal thread in your current stem tapped deeper and make up an even longer blind nut to utilize the new deeper thread. There is plenty of meat in the stem to allow for this.
There is no reason in my mind why significantly increasing the threaded connection between the stem and the blind nut wouldn't entirely stop this from happening again- ie instead of mucking around with 20mm of thread (or the 15mm or so it looks like you were using) give it something like 50mm or more of thread in the stem and 50mm or more of thread on the blind nut- make the blind nut out of whatever you want, by extending the threaded connection significantly like this, even if you torqued it till your bars barely turned I do not believe this would happen again.
Extend it enough and you could lift the bike from the blind nut and no amount of Jenna treatment should be able to strip it
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Old 05-12-2013, 05:33 PM   #836
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Old 05-13-2013, 07:49 AM   #837
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Quote:
Originally Posted by ontic View Post
Sorry I don't mean to argue especially as you are in a shit of a situation, but I beg to differ on that mate. Steel to aluminium thread might not be the best thing in the world but so long as galvanic corrosion isn't happening and anti-seize is used it sure as hell beats aluminium to aluminium thread

My bad....I guess my sense if humor is hard to read in a post. My smiley didn't come through. Edited. Anyway...after sleeping on it and reading your suggestions I'm off to a drill press to utilize the length of the stem per onitics easy and cheap solution. May try to fan up a steel stem bolt from swing arm bits. Being proactive has always bitten me in the ass, I should just go back to being lazy. I was better at that anyway. Thanks all!
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Old 05-13-2013, 10:00 AM   #838
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Haha, no dramas, I did miss the humour but that is OK
I just had a measure of one of the swing arm bolts- there is 24mm of thread(20mm OD), and around 24mm of thinner unthreaded section above it (17mm OD).
The swing arm bolt has a nut that I welded on top of the threaded section and cut the remaining unthreaded section off flush-
With your already stipped out section, following this strategy won't gain you much thread... You could weld the nut up higher on the unthreaded section to get your blind nut thread down to your new tapped thread...
I wonder though if it might just be easier to try to find a nice longer bolt of the same OD/thread and adapt that for the purpose- then you could really gain some extra thread and security.
Of course this relies on you having the right tap for this thread gauge.

Alternatively, if you have any problems finding a bolt and/or tap in this gauge thread, considering there is a lot of meat inside the stem to play with, you could abandon the current gauge we are using and just drill and tap a new gauge thread suited to whatever a really long/fat bolt/blind nut you find...
Options options
One definite thing on my list is to get this steel blind nut plated in something- not going to be pretty once it rusts up!

Whatever the case, good luck with the repair.
I've been fiddling with all the new stuff on my handlebars for a few days now and have finally got everything fitted up- involved a lot of time consuming metal fab and mucking around. I think it has worked out very well.
I'll have to post an update to my poor abandoned thread soon.
night,
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Old 05-13-2013, 02:53 PM   #839
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So....I pressed the stem out.

 photo 91690D69-CD36-4FD7-8498-7A1AFA31D6C9-4976-00000933C16BAA2A_zps3f3a8140.jpg


 photo 154A7C49-DA98-43BD-9125-715CF9A4BDD9-4976-00000933D9AF58D6_zps46f903f5.jpg

Then I pressed out the KTM stem.

Then had a wild idea.!!!!

 photo 49AF2995-E8A6-41B2-8739-C0A797C18629-4976-00000933D06D509E_zpsfe345197.jpg


Looking into my options.....the lathe at the shop wasn't large enough to hold the stem, and they only have a small drill press. The machine shop is set up for something Terry is working on, so I didn't want to monkey with the lathe. I left it with him giving him 3 options. Fix the existing stem by drilling deeper and retaping, turning down the new KTM stem and still drilling deeper and retaping, or..........make me a steel stem. Dunno which route he'll take. It's all dependent on time and how much weed he will smoke.
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Old 05-13-2013, 04:14 PM   #840
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@Jason....come hell or high water I'll make it to the RR'13. I've got Russian Jew ingenuity on my side.

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