fork problem

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Joined
Jul 29, 2002
Messages
201
Location
Zwiesel, Germany (Bavarian)
Hello,

I hope I can explain the problem.

When I lift the handlebar while standing beside the bike, the fork goes not back in the normal static sag position.

When I compress the fork a few times, it goes back to static sag.

The differenz between the two positions is about 2-3 cm.

I have loosen all the clamps of the wheel axle and the upper triple clamp.
I don´t think the fork is twisted. The seals are ok and protected from dirt.
The hydraulic stop is well filed for fitting with the 48Nmm springs.
(I thought first the reason is a friction between this inner parts and checked it)

Are the Du-bushing´s ø 48 the reason for this? Surely not changed for a few years.

And is a update tip available, or should I buy the 2001 parts for my 2001 WP fork?


Thanks in advance!
husa98
 
imo, i don't think that's unusual. i've always had friction in that manner. whenever i check ride height i will work both ends and then let it settle. big difference from just letting gravity settle it.
 
Thank you ned,

I think you are right.

I have yesterday checked this by a KTM EXC 250 from 2005 by my husaberg dealer.

It was the same. And this fork has 3 bushings.

He says: dont worry

Now I will relax, but although change the bushings at the next opportunity.
 
To confirm, gently bounce the handlebars. You should get a smooth friction free response from the forks. If not, loosen the right hand fork axle clamp only and get someone to tap the underside of the fork with a soft hammer while you bounce and feel. The fork leg can move a couple of mm and if not centred properly will cause binding. You can even just pull it bit either way to confirm.

Steve
 
on last monday I left my bike by an husaberg dealer 200km away from me, because I went further for a short holiday trip.
He is a husaberg dealer since 1990 and a active dirver since 1977.
Checking my suspension he told me that "nowbody" can drive this.

(much to my regret he had no time to repair my fork in the two days.
Today I picked it up and went home. )

"no" rebound in the fork.
and roo less rebound in the shock
And the bushings probably damaged.

That´s his opinion

Please explain me: have the 2001 fork a Midvalve?
where is it in the parts manual?
I don´t get the hang on this, sorry!

and what is the stock setting for the rebound shims, and "the best" for a 4.6Nmm fork spring?

Have I to stiffen the rebound shims to slow down the 4.6 N/mm springs?
 
husa 98

forgotten your name but i'm sorry to hear that the forks aren't right. i did mine one step at a time and learnt and understood as i went. lots of work, lots of time and care. hope i can help some how!....

no rebound can be because you haven't enough oil in the forks.

regards

Taffy

regards

Taffy
 
Fork nomenclature is very inprecise and undescriptive. Also, don't listen to what people say, try instead to figure out what they mean, they will generally say somethingt else that doesn't really make sense, what they meant to say could still be very valid. The 2001 fork may, like my 2000 fork was, be equipped with a checkplate on the piston, the checkplate is not even a proper checkplate, it is a pack of 4 shims prevented by the piston tap from flexing as much as a MV. If there is a midvalve it is about the same pack of shims, and then some, that were called a checkvalve, only the piston tap will allow them to flex a bit more to unload some of the high speed force on them. As you can see it is a matter of definition on wether to call it a mid valve or a check valve. They do the same things and look much alike but the MV can flex a bit more easily and further than the checkvalve does.
The event rebound is when the fork extend back from having been compressed, the property rebound is the damping of the same movement. The guy said there was no rebound. Doesn't give the picture. Hard to tell if the forks stuck compressed and refused to rebound or if there was no damping if they did. Doesn't make sense unless you saw it. It is the springs that should make it happen, make them rebound. Without oil no rebound damping. He could also have meant too little rebound damping for his taste. Maybe the bolts of the lower gabelbrucke are tightened too hard so that the fork sticks compressed. Something could be broken or I may not understand the problem, or if it is technical or indeed a problem at all. Are the springs made for the forks? Are the fork legs straight? If you could remove the springs and check each fork leg for smoothness. Spin them idividually at different extensions, should tell you if they are binding somewhere or are bent. Try filling the seals with silicone grease if they want to stick hard, they shouldn't.
Thanks for writing.
Happy holiday.
 
Smorgasbord said:
Fork nomenclature is very inprecise and undescriptive. Also, don't listen to what people say, try instead to figure out what they mean, they will generally say somethingt else that doesn't really make sense, what they meant to say could still be very valid. The 2001 fork may, like my 2000 fork was, be equipped with a checkplate on the piston, the checkplate is not even a proper checkplate, it is a pack of 4 shims prevented by the piston tap from flexing as much as a MV. If there is a midvalve it is about the same pack of shims, and then some, that were called a checkvalve, only the piston tap will allow them to flex a bit more to unload some of the high speed force on them. As you can see it is a matter of definition on wether to call it a mid valve or a check valve. They do the same things and look much alike but the MV can flex a bit more easily and further than the checkvalve does.

Thanks for the statement!

The event rebound is when the fork extend back from having been compressed, the property rebound is the damping of the same movement. The guy said there was no rebound. Doesn't give the picture. Hard to tell if the forks stuck compressed and refused to rebound or if there was no damping if they did. Doesn't make sense unless you saw it. It is the springs that should make it happen, make them rebound. Without oil no rebound damping.

The air gap is 135 mm, and I don´t think I have lost the oil.
But I will check this.
(I can´t tighten the base valve body on the right side correct, but it was only one drop of oil under the rubber cap)


He could also have meant too little rebound damping for his taste.

Yes, this was meant! I wrote "no", "" was standing for nearly no. sorry.

Maybe the bolts of the lower gabelbrucke are tightened too hard so that the fork sticks compressed.

I don´t think so. standing near the bike and pull the handlebar up and down, is to less for the 4.8 springs to pull them down till the bushing of the inner leg arrives the gabelbrücke.

Now I have bought new 4.6 springs.

Something could be broken or I may not understand the problem, or if it is technical or indeed a problem at all. Are the springs made for the forks?

Original new WP spings.

Are the fork legs straight?

I hope so! But I haven´t checked it until yet.

If you could remove the springs and check each fork leg for smoothness. Spin them idividually at different extensions, should tell you if they are binding somewhere or are bent. Try filling the seals with silicone grease if they want to stick hard, they shouldn't.
Thanks for writing.

When my dealer got the bushings tomorrow from the husaberg stock, I will check all this.
But please: I will check the correct shims for the rebound!
To avoid a work for nothing!

and i have to check the" Problem solving" point from the doc, the right rebuilding from the rebound.

Holidays only 3 days after a race last sunday, and this saturday is the next race (and this time against my friends !)

Thank you!



Happy holiday.
 
I have checked the fork today. I did only the left leg!

The o-ring on the compression piston was broken.

The check valve is 4 x (8x24x0,1)

The rebound was:
2 x 24d
1x14
1x22d
1x20
1x18
1x16
1x14
1x10x0.3
1x16x0.25

That seems softer than the standard.

I changed to
2 x 24d
1x22d
1x14
1x20
1x18
1x16
1x14
1x10x0.3
1x10x0.3
1x16x0.25

I have no further delta shims on stock...

The oil ist refilled to 130 air gap.

The rebound clickers complete closed clockwise to "+"

No improvement!
The fork rebounds too quick.

Ok, I have to afflict with the fork tomorrow at a 2 h crosscountry race.


And next week I throw the scrap away and buy a beta.Maybe.
 
There is goodness in a fast rebound as long as it doesn't launch you and make the ride a bouncy bouncy ride. Keeps the rubber in contact with the ground and makes the fork ready for the next bump in time where there are lots of them. By using heavier oil the rebound can be made heavier. But these forks don't like very heavy oil unaltered as they can give a kind of awfully unpleasant rebound bangs when riding fast in repetitive full stroke stuff, if filled with that heavy oil. Do you use Motorex 5w? It should be OK.
I'm sure that with the clickers closed, my fork would pack down immediately and deeply. What is it with the other fork leg that you didn't check? Could your delta shims have rotated out of engagement? I t can happen if a pneumatic impact wrench was used carelessly on the fork. Or is the checkvalve out of order? Don't throw it away even if you get a Beta next week. You should look at a KTM, but then, they are WP sprung too.
If you have too little compression damping the fork will compress too far and the they will then launch you even if the rebound is good. It is always hard to say anything about something that you haven't seen or felt.

Regards.
 
i once had all the rebound shims come loose on the tap and this made the front end stand up like a stag rutting.

could this be it? were all your shims fanned out. by checking only one leg you may be missing the problem?

regards

Taffy
 
thanks for the replies

I will answer in a few days.

At the moment I´m frustrated.

I checked only one leg of the fork on friday. because I don´t feel like to work late in the garage one day for my birthday and the race on saturday.

The race was totally different to last year, with typical enduro elements.
Not like a crosscountry race.

along a runnel, through a duct, with the head nearly the handlebar, and so on.

After 1,5 h the engine gets a fizzling noise.

First I thougth the tube of the cooler is untight.

After 5 seconds tis noise gets louder.

I was luckily short to the checkpoint, finished the lap and checked the bike.
But the tubes was ok.

I stoped the race to avoid a larger damage.


...will continue
 
lets go on...

the delta shims of the one leg was in the right position.
but a great difference to taffy´s proposal in the doc.
(only 2 of the 24 d, and not 4!)

Which should i try?
24d, 24d, 24d, 16, 24d, 22, 20, 17, 14, 12, 10
or you can try
24d, 24d, 24d, 14, 22, 20, 17, 14, 12, 10

or another tipp for me?

second is the missing of changing by the clickers.

I will check the rebound needle. What to looking for?

with a new piston ring and new bushings i will do "last" trying.
Otherwise I give it to a suspension specialist.
 
check the thread "tuning forks for enduro" or whatever for my latest rebound stack. sometimes i forget to u8pdate the doc....

as the two sets go -either will do - honestly! the rule with rebound is that you need to make larger changes to feel a difference.

for me, check that you have been getting the fork oil heights right, this is most important. make sure that the tap nut is tight at the base of both rebound stacks.

regards

Taffy
 
Smorgasbord said:
What bike is it on which this WP fork is attached, is this the original fork?

Husaberg FE 501e, 2001, original fork.
 
Hi taffy, Hi smorgasbord,

checking the thread "tuning forks for enduro" makes me stupid.

so many alternatives, mixing newer parts with older parts... that beats me!

I see that my rebound stack should be the original yet, because the 2000 hast the same.

Please filter the result of the discussion out for me!

I will order the parts I need by my deale.
bushings, piston rings, rebound needle, and the shims!

thanks in advance!
 
OK, you already know what the 2000 rebound stack is for the 43 fork. It seems like they used the same for your 2001 48 fork.
Here is the modern rebound stack that almost all use today, almost regardless of other variables. But this is for the less raked fork found on KTMs and later Husabergers that also still run the 14 mm piston rod. (I dont know about the latest 12 mm rodded forks.) As Taffy said, rebound seems more tolerant to changes so this might work in spite of the rake you have on your fork. No guarantees though, bear in mind that I've never tried it myself. Other people are probably more suited to answer this.

The hole in the middle is 6mm, and D stands for the triangular "Delta" shims.

Piston
24D X 0.1
24D X 0.1
24D X 0.1
24D X 0.1
16 X 0.1
20 X 0.1
18 X 0.1
16 X 0.1
14 X 0.1
10 X 0.3
16 X 0.25
Nut

Implied in what was said, that rebound is more tolerant, is that the sweet-spot on compression is harder to find. Only judging from the clickers, I easily get acceptable rebound damping within a 5 click span. On compression, one click off and it's off adjustment, there is no acceptable span but spot on. On the other hand, once there they hardly ever need adjustment while the rebound clickers are used more often, but then probably beacause of it. Others may have different experience.

Regards
 

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