fork tuning for enduros

Taffy · Dec 9, 2005

ok i'm rebuilding my own forks

new bushes (4)
new dust caps (2)
new seals (2)

what about the nuts off the rebound rods?
the steel washers next to the seals look good
what weight oil?

can anyone tell me what the shim stacks are for '06 or '05? i'd like to compare?

regards

Taffy

Brendan · Dec 9, 2005

Re: fork rebuild

I use mobil 1 synthetic atf in mine.

LeFrog · Dec 9, 2005

Re: fork rebuild

Motorex 2.5W

Taffy · Dec 11, 2005

Re: fork rebuild

there are plastic piston rings on the rebound rods. not sure how often they should be replaced?

my compression screws were 24 out from closed and there are only 30 clicks anyway!

can anyone advise if i give my present shim stack configuration?

it's just that the forks were lovely yet i still ended up removing preload, removing oil and outting the clickers just to start getting full travel. that's not very good is it!

if i can get no help here is there anyone i can mail who you trust with the info?

regards

Taffy

BendBerg · Dec 11, 2005

Re: fork rebuild

Hi Taffy, There are a couple of rules that I follow when doing suspension work. #1 Lighter weight oils will offer more responsive suspension on small bumps. Adjust the oil Level to add anti bottoming resistance(only the last couple of inches of suspension travel is effected by oil height). #2 If you have your compression adjusters backed all the way out(softest settings) then you springs are too stiff, go to the next spring wight down(example..If you currently have 4.2 kg springs, drop down to a 4.0kg spring). Personally, I do not care for preloading fork springs, it seems to make the fork harsh on the small bumps and tends to make the front end push(on dirt..supermoto,may be different). I have also had very good luck with the RaceTech gold valve, it is VERY tunable, the kits come with a wide variety of shims and charts to tune by. If you are looking to fine tune your suspension yourself, this is the way to go! As far as 04-05 shim stacks, I don't know. Hope this helps.

Taffy · Dec 11, 2005

Re: fork rebuild

bendberg

thanks for that. concur with the lightest weight oil known to man etc. i use 2.5W.

the fork springs have just gone up from .44 to .46 and even then the .44s were measured as .42 or .43 because they'd lost their guts.

i pulled out the 15mm of preload and yet the forks didn't use a MM more of travel so we can say that it's the air gap or the shimming, right?

can you tell me why o why the books all say that the air gap should be 110mm on these and yet nobody seems to be able to run less than 120-130mm air gap...

i mean WTF that about?

cheers!

Taffy

JoeUSA · Dec 11, 2005

Re: fork rebuild

Taffy said:
ok i'm rebuilding my own forks

new bushes (4)
new dust caps (2)
new seals (2)

what about the nuts off the rebound rods?
the steel washers next to the seals look good
what weight oil?

can anyone tell me what the shim stacks are for '06 or '05? i'd like to compare?

regards

Taffy

Here you go Taffy,

http://www.husaberg.org/modules.php?nam ... fork+shims

regards,

Joe

BendBerg · Dec 11, 2005

Re: fork rebuild

Hey Taffy, in reference to the air gap. People may find that running there oil at 110mm is offering a harsh bottoming condition. I have had people refer to a hydraulic lock type condition when running the oil level too high. Maybe with more volume available within the fork tube, the expansion of air(from heat) has less effect on fork action? Just a thought(dangerous I know). Also pre-load shims, oil height, and air pressure have no effect on travel. When adjusting your valve stack(shimming), oil weight and height, we adjusting the action of the fork. P.S. really check out the RaceTech stuff! A tinkerer like you will love it!

Taffy · Dec 11, 2005

Re: fork rebuild

yeh but bendy

how can the WP factory say 100-110mm and then everyone runs 120-120mm. i mean it's not a vague issue really is it? your left saying WTF, how did we get here?

thanks for the help though and i've been to ktmtalk, independant suspension and UHE and ....i'm getting heaps of info back slowly.

nothing from dave186 or FC550 yet but you never know....

regards

Taffy

BendBerg · Dec 11, 2005

Re: fork rebuild

I sense your frustration, it's like jetting a carb...it is different for everybody. Good luck. :cheers:

Taffy · Dec 12, 2005

Re: fork rebuild

has anyone ever been to the track (or wherever) and removed the compression stack out the bottom of the fork whilst they were there and played around a bit?

it's just that i like to do my testing back-to-back.

regards

Taffy

mikst · Dec 12, 2005

Re: fork rebuild

By a coincidence, I know that Martin Lind used 112 mm SAE 5 in his bike -02.

This year I have tried 110 mm and SAE 5 and I think it's better for me. The fork does a better job in the MX-track.
However, I would like a more progressive characteristic. A little softer in the beginning and much more in the end of the travel.

Parsko · Dec 12, 2005

Re: fork rebuild

Taffy,

Check out this document. You might find it interesting. When it comes to shocks, there are few that have better insight than the Penske guys. Granted, this is for race cars, the concept dirrectly applies to dirtbikes, except we have 2 wheels. It is extremely informative, if I remember, it's been a while since I've read it through. But, you're the type of guy....

Though, the design is different, we too have shim stacks that perform in the same manner. They are adjustable too. This document will teach you more about shocks than most places. About page 16 is when I start to feel like I am reading porn... TMI

Penske Shocks

Enjoy, hope it helps.

-Parsko

PS- Changing shock guts is not something I personally would recommend doing at teh track. Particulate contamination is a major no-no to this type of component. Treat it like you would your main bearings. You ain't made of money, I know, but this is one of those things where it'd be nice to have 2 sets of....

Taffy · Dec 12, 2005

Re: fork rebuild

i've tried to find my paperwork with all the standard 2002 shim stack numbers but i can't and the only other place i put them was here at UHE yet i still can't find them in the archive that json put up yesterday (cheers J!).

someone has told me that you can undo the compression stack with all else in situ as long as the forks are pressed down?

parsko
i would pick a dry test day and wouldn't be frightened of trying things. it's never stopped me before...

i'm a great believer in back-to-back testing if you can afford it. the european ebay site has nearly 200 items on it most of the time now and i've seen those forks put up regularly. however it's another bloody expense isn't it...

anybody else know what's in their shim stack? wanna know what's in mine!!!!!

regards

Taffy

BendBerg · Dec 12, 2005

Re: fork rebuild

Parsko, the Penski shock people are awesome! Your analagy for the technology is right on..the only difference..the car shock technology came from motorcycles! they are just like bikes but with four wheels. Taffy, I wouldn't mind knowing what W.P. did for a valve stack. As for tunning at the track, If you have the time and an area to do the work while keeping the interals clean, then go for it! IMHO your springs are too stiff.

Brendan · Dec 12, 2005

Re: fork rebuild

I have left mine together, and turned them upside down, squished them down a bit, and used an impact wrench on a low setting to take out the basevalves. Maybe you should try a mid-valve setup along with the base valve. There are a number of free stacks on ktmtalk. I know a guy that really likes his mid-valve setup, and I could probably find out the stack info if you want.

Taffy · Dec 13, 2005

Re: fork rebuild

bendy

i was running .44s and they bottomed rarely. they felt nice but i always thought they were under weight.

dwight rudder on the other hand went down to .40s and so i guess for me .42s would have been obvious.

strong springs-soft damping required. and i haven't got it. i'm going to rebuild them with a 140 air gap this time and i may even change some shims.

there is a bloke called WPman on ktmtalk but he doesn't respond. probably because i'm on a husaberg!

regards

Taffy

Taffy · Dec 13, 2005

Re: fork rebuild

ok there is some interesting stuff going on at ktmtalk.com aon their suspension site. only ktms are running WP in serious numbers so it seems to be the obvious place to be.

this is my compression/base stack (all at .1 unless stated):

5 x 24, 14, 22, 20, 18, 16, 14, 13, 12, 11, 9 @.3, [email protected].

it appears that if i pull out the "13-12-11" i have the same set-up as the standard '06s.

i've seen 3 x 24, 14, 3 x 24, 22, 20 the same....

someone has modified that to:

3 x 24, 14, 1 x 24, etc etc

i now have a good idea what i wnat to try. another thing that has come out is peoples willingness to try different weight springs in. a .42 with a .40 etc etc.

i feel my compression clickers need to come back to the middle setting whatever i do? the air gap was happily left at probably 125-130mm and i need to check as i've found in old archives that i had 140mm at one time and this could be my problem!

yep! lots to try!

regards

Taffy

CAN you drop the shim stack at the track without ripping the rest of the fork out?

c'mon someone!!!!!

Taffy · Dec 13, 2005

Re: fork rebuild

ok

hit a new problem today!

went to have the rear shock rebuilt and the dealer says "where's the schrader valve to re-pressurise?".

well! how do we re-pressurise these things?

can anyone help with this terminology?

"rebound valving"?
"check plate"?
"float change from 1.25 to 1.35"?

i am going to get to grips this time but i'm not getting any help!

here is another.

it's 6 months since the forks were done and i've raced 6 times, 8 at the most. so what is the service life of everything for an enduro machine?

oil?
bushes?
fork seals?
dust caps?
shims?

there are more questions than answers and the more i find out the less i know! yes there are....

regards

Taffy

Brendan · Dec 13, 2005

Re: fork rebuild

You can remove them while on the bike, as long as it is an the proper angle so you fork oil doesn't come spilling out. Have fun dealing with your other bike fluids and I would use a tie down strap to help compress the forks.

I use Mobile 1 synthetic atf at 150mm, .42 springs and the following base valve stack with stock check plate.
.10x24 High speed
.10x24
.10x21
.10x18
.10x15
.10x12
.10x10
.30x09 Clamping
.10x14 Spacer
.10x16 Spacer
.20X18 OEM Spacer

You could try Terry Hay Stacks
Compression
3x24x.1
1x21x.1
1x19x.1
1x17x.1
1x14x.1
1x12x.1
1x11x.1
1x.10x.2

Rebound
3x24mm Delta
1x16x.1
1x24mm Delta
1x22x.1
1x19x.1
1x16x.1
1x14x.1
1x12x.1
1x11x.1
1x10x.2

Mid Valve
4x24x.1
1x19x.1
1x14x.1
2x11x.1
1x15x.1
1x20x.1
1x24x.25

fork tuning for enduros

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