fork tuning for enduros

Re: fork rebuild

went to swaffham again today. this was the 6th and last time before i ski next weekend followed by 2 race meetings.

i have added some shims to get the bike better. in the BV i added a further 24 for this: 24, 24, 14, 24, 22, 19, 16, 13, [email protected]

i softened the MV by installing a 15mm 'splitting' shim for: 23, 23, 15, 20, 18, 13

the rebound i added two shims: 24d, 24d, 24d, 15, 24d, 20, 18, 16, 14, 12, 11, [email protected], [email protected], [email protected]

i brought the float out to 1.25mm (or 50 thou as you might say!). oil level is 150mm.

the forks were perfect! i couldn't fault them, not in icy weather on a damp slippery in parts track. i still have 35mm unused which i guess you could say is there for a rainy day! but i didn't touch the clickers all day. not even once! the comp was out 15 and the rebound out 12 and they never moved!

i later put 20mm of spacers in (that's a preload of 14mm) on mine and the bike again skips over the top of whoops. not as pronounced as the 25/19 from last week but all the same BETTER!

i now have to pluck up enough courage to buy some .48s and install one of them!

i also have a subtank system ready to go.

the bike is presently being let down by the rear. i spent the day adding some compression and rebound until i was halfway on both sets of clickers.

but the rear shock just isn't progressive! it plunges all the way through it's travel on the facing face of woops. i added preload (2 full turns) and the bike turned quicker and the shock didn't bottom out.

but with the preload now at 253mm i'm now no further forward than when i had the PDS7. i need terry's telescopic needle or a PDS4?

i don't know which and at the moment i'm still waiting for terry to ship the stuff to me. get this rear shock sorted and go racing then we'll see what else needs doing.

thanks for your advice Per, it worked a treat and i did the work myself. saved a bob and now know what goes into a set of forks.

regards

Taffy

Re: fork rebuild

Taffy
sounds like you are moving in the right direction
looking at the rebound stack it looks like it should have fast low speed
rebound move 15mm to between 24mm and 20mm one way to know
this if it does not pack in the woops and tryes to stand you up when exit a
turn
you probably will have problem with 2x23 sucking through MV piston
judging from your shock setting your bike should be more balanced
it shouldn't blow through the stroke what is your high speed setting on
the shock looks like you need to tighten high speed on the shock
so long
VIKING

Re: fork rebuild

Per

i will move the 15 so that all 4 x 24D are together.

you're right about the HSC on the rear shock. i found it when i got home to be 2.5 turns out from closed (3.5 is the maximum) i'm yet again disgusted with myself for this. i had it down from 3 months ago at 1-turn out from closed. have i been sabotaged?!?!?!?!?!?!?!?!

i will give it more of this next time-lots more!

yes, the bike is very well balanced now and doesn't yaw (too and fro) anymore.

on a different circuit i'm hoping it may be interested in bottoming out-orcome close but at present i have not even changed into third gear. so that tells you that 'woods' means 'woods'!.

what do you mean by the '2 x 23 may suck through the MV?'. are you serious? a shim being sucked through on rebound?

i have one other thing i must address ASAP, and that is that the bike doesn't dive under braking into corners and as such i'm having trouble 'railing a berm' especially a low speed, tight turning berm!

i'm thinking of softening the MV again (with a hardening of the BV at the same time) and opening the float back to 1.4-1.5mm? will either or both of these changes help?

regards

Taffy

Re: fork rebuild

Taffy
I could imagine that your bike dives in the braking bumps based on your
valving/oil level combo also keep in mind that a stiff rear spring/stiff
low speed comp. will lever forward keeping fork far into the stroke.
based on your weight I don't think that you need stiffer fork springs
46 should be plenty I run 42/44 combo and I weigh 195 lbs and that felt
fine in the woods, that combo was a little light on sandy MX track with
big rolling woops in 4th gear but that was with a custom mid valve
(see gallery)
this is what I would recommend
1/oil level 125-115mm
2/ fix mid valve stack gap 1.5mm yes I am serious shim the can suck through piston the hole is big and the shim is only .10 mm each and
metal fatigue is very real pieces of shim in a aluminium tube bad :evil:
of course fix rebound
3/ stiffen BV with more 24 and put a 16x.10 separator shim between
first and second 24 shim if it feels mushy go to 18x.10
4/ if you still cant turn in tight woods slide fork up to first ring on fork tube
this is for 02 frame geometry
so long
VIKING

Re: fork rebuild

just weighed everything electronically at a waste paper mile. level pad.

bike weighs
116KG which is 255 pounds no fuel
front was 56KG or 123 pounds and 48.2%
rear was 60KG or 132 pounds and 51.8%
i weighed 100KG which is 220 pounds in my gear. didn't see what it was with me sat or stood-wish i had, would have been nice to know what happens.

bike has handguards, sidestand, front and tail light, tall seat, heavy duty tubes

doesn't have: leccy boot, battery, balancer, speedo, horn or rear brake lever set-up, any engine guards at all.

the above is from another thread but i think it'll look good and relevant here. i checked and the KTM450EXC is about 1LB heavier and the 450SX is just 230LB. trouble is both bikes carry their centre of gravity lower than mine. the SX is like a toy....!

i'll do the work for this thursday but i'm away skiing this weekend and it'll have to be done for a race meeting the week after!

thanks again.

Taffy

Re: fork rebuild

well i feel i'm pretty much where i wanna be now and from now on i'll try and exchange things - fast for slow, MV and BV etc.

MV is now: 23, 23, 13, 20, 15 which means that the 13 crossover softens things at LS and MS i think. the last shim (13) is gone and the 18 is a 15 so i suggest it's much softer and more oil will be travelling north from now on. float is up to 1.55mm.

the BV is as per your recommendations initially: 24, 18, 24, 24, 22, 19 which is a 24 added and the crossover coming in behind the opening shim to help with bleed? but then i softened it with a 15 not 16, and 11 not 13.

24, 18, 24, 24, 24, 22, 19, 15, 11, [email protected].

the oil level will be 140mm from 150mm. packing/preload is back to 15/9mm.

i hope that i'm swopping one for another.

but i need a lower front end under braking for tight corners as my only clear problem at present. i can't rail berms as the nose won't dive braking (atr slower speeds?) maybe because i'm sitting by then?

i'll test the above and deal with anything at the track. i have deliberately gone OTT with the MV and trust the BV can be hardened to compensate if necassary whilst there should be more oil up top for good rebound. this in turn puts pressure on the 2 x 23s.

i will be testing preload on the rear for steering response.

i'll test the HSCD and LSCD on the rear.

i may add oil level or (but if the 140 level takes away travel) - i won't!!! it will effect rebound a lot i would think?

may raise the forks for weight transfer/cornering.

i have drilled the caps for subtank tests sometime!

that's it for now! i will try and ride tha bike somewhere next week.

regards

Taffy

Re: fork rebuild

only a short ride yesterday before hitting trouble (will explain elsewhere) but the forks were excellent and the rear shock the best i've ever had.

can't wait for 2 days of racing this weekend coming.

regards

Taffy

Re: fork rebuild

first new circuit for the suspension on saturday. the forks bottomed out off some third/fourth gear drops quite easily and the rebound was a little amiss from such a deep dive. so i look forward to adding some more oil this week.

the bike turns quite well into turns but slow ones are bad still. although i get dive if i use the front brake it's all from too high to just high and not low which is where i used to be.

i have a little preload on the rear left i may try and i'll lift the forks through about 5mm more. i'm probably going to need more HS shimming on the compression though and may even need to remove the 6mm preload i have. i don't really want to do this because the bike seemed to deteriorate the last time i did this. may have too though.

one thing though; i get there very late and the tyres were still at 20LBs. i was so late i went straight to the grid. so:

as far as they behaved generally i'd have to say that thew damping is now too soft and felt like a bike with no/little oil in the forks. all the little hardpack stuff has the front end working feverishly and i don't think it followed the track too close. this made flick backs dangerous as you might try one with the tyre well clear of the ground. this could all be the tyre unfortunately.

keep you posted!

regards

Taffy

Re: fork rebuild

Taffy
The quest for suspension nirvana is end less it seems that one are
moving ahead only to take two steps back in some other area

far as your handling woes it seems by your description
A/ fork seem to be diving, fix raise oil level and /or increase LS dampening
via clicker or the LS part of shim stack ( a stiffer HS part of shim stack
wont do anything to hold you up going into the corner)
B/ your fork seems to be packing in other words as you are going thru
braking bumps into the corner the does not have time to extend
before it hits the next bump fix unscrew fork rebound
C/rear shock seems to be topped out, not enough sag or your spring
is too stiff in the middle
obviously 20 psi in the tire doesn't help and correctly setup Husaberg
corners like hero my former Husky dealer and ISDE/Swedish champ in Sweden told me why are you messing with your bike so much just ride it
remember speed comes from you they say that it is 25% bike and
75% bike I was hopeless my tinkering gene had already taking over
so long
Per

Re: fork rebuild

VIKING said:

Taffy
The quest for suspension nirvana is end less it seems that one are
moving ahead only to take two steps back in some other area

far as your handling woes it seems by your description
A/ fork seem to be diving, fix raise oil level and /or increase LS dampening
via clicker or the LS part of shim stack ( a stiffer HS part of shim stack
wont do anything to hold you up going into the corner)
B/ your fork seems to be packing in other words as you are going thru
braking bumps into the corner the does not have time to extend
before it hits the next bump fix unscrew fork rebound
C/rear shock seems to be topped out, not enough sag or your spring
is too stiff in the middle
obviously 20 psi in the tire doesn't help and correctly setup Husaberg
corners like hero my former Husky dealer and ISDE/Swedish champ in Sweden told me why are you messing with your bike so much just ride it
remember speed comes from you they say that it is 25% bike and
75% bike I was hopeless my tinkering gene had already taking over
so long
Per

Click to expand...

hello Per

i'm learning a great deal. i'm quite happy to keep learning. the previous set-up was superb in slow soft woods. as soon as you go faster than 20mph though the bike changes.

i have raised the forks 5mm. i have added 30ml to each leg so that 155mm air gap is perhaps now 140mm i would think. i have changed the BV shim stack as follows:

was: 24, 18, 24, 24, 24, 22, 19, 15, 11, [email protected]
is now: 24, 20, 24, 24, 24, 22, 19, 15, 13, 11, [email protected]

as you say 20PSI doesn't help.

we'll see!

regards

Taffy

Re: fork rebuild

raced today on a beautiful circuit. it had deep mud, ditches, steep turning climbs, an MX section, bone dry in parts the lot.

i found the suspension to be excellent! i used all bar 40mm of travel and i think i need that 'just in case'. the bike seemed to corner beautifully without falling in or climbing out of the berms.

didn't notice any dive on the front on the braking, bike felt normal and that's all i can say.

on one or two corners the front tyre wnated to move away and secondly i felt that the forks weren't great over fast dry/hard but small stuff like stones.

the bike isn't at all tiring to ride. the raising of the forks meant that drop-offs gave a little head shake but it really was nothing today.

i had one of my best ever ST times and beat a few mates who normally get me. and when they started sending out the experts with us so they could make up a lap: well many couldn't touch the bike and that's a first!

i might take the 20 in the BV back again to an 18 for 24, 18, 24, 24, 24 etc.

regards

Taffy

Re: fork rebuild

Taffy
sound like you are gaining on your suspension endeavor
what kind front tire do you have on the bike certain tires could make
a uneasy feeling over rocks and hard pack
it not easy to mod mid valve further without sacrificing reliability
you might have been fus tight on the rebound
so long Per

Re: fork rebuild

the best mate!

michelin S12's are my tyre of choice. you have often said that my forks DO dive and even 'pack' but i've found the opposite. iraised the forks 5mm just to improve the dive and get more going into corners.

the bike feels like it did last season now though so i think that it's around about the same as it was then. it is definately worse at slower speeds.

i hope that pulling out one 24 from the BV i'll get a little more LS 'nod' as i arrive at a corner.

would a larger float be good? i have 1.55mm at present which i think is more than enough but i read from someone who knows little of the inside of forks that he thought the float looked to be about 2mm on the latest bikes from katoom?

can you tell me what raising the oil level does in a) compression b) rebound c) handling?

regards

Taffy

Re: fork rebuild

Taffy
lets start with tires, each tire has its moment in the sun S 12 is a soft
terrain tire with tall knobbies and soft carcass and design for a mouse which makes them wiggle around alot on hard pack, what happends is that the knobbies fold when braking and cornering meaning that the knobby is not flat on the surface, thats most likely the reason that your front end wanted to wash out in the corners, woods riders likes that tire since it conforms to rots and rocks personally there is 3 tires that I like
Pirelli MT 44 for the wood mud and MX tall side wall carcass stiff enough
Pirelli MT 16 for the woods when its dry tall side wall carcass like S 12
the knobby fairly is large so it don't wiggle around alot
Pirelli scorpion for the woods and MX dry and wet hard pack does not have
tall side wall the carcass is stiff in the side wall and soft in the tread
I don't use this tire in the cold rubber compound gets too stiff in the cold
NO I am not paid by Pirelli

now to the fork increased oil level (decreased number measured) will
make the fork progressively stiffer
A stand taller in stroke
B make fork boingy when bottomed hard in other words rebound tends to
be less consistent through its rebound stroke
C more work to compress the fork for good cornering your fork angle is
less prone to dive compared to newer husaberg
a larger gap in the MV tends to make fork blow through the stroke
most noticed in big braking bumps you have reached the limit in what you can safely do with the mid valve thats why I no longer use stock mid valve
I haven't looked closely at the 06 KTM fork to know what done in detail
taking out a 24 would most likely not give more dive for cornering
lower the oil level/ less spring would have more of an effect
so long Per

Re: fork rebuild

Per

i'm sure you're right about the S12 and it's sidewalls. it's just that it seemed worse than normal.

we can surmise that i'm either getting more pressure on the front and it's folding or that the suspension is something to do with it. don't forget that i've raised the forks 10mm overall (i have the KTM125 14mm offset triple clamps in)

i was looking for more HS but small bump control. the rest, i can't get used to yet but feels pretty good.

again many of the things you say are so true: the rebound is wayward on very fast flat G-outs.

i didn't have trouble in braking bumps which you have often stated-none at all but i do have trouble in continuous bumps when for instance going across acceleration stutters - the front end used to sink and absorb everything - now it's a bit better.

the only thing i'm not nodding in agreement with is that the forks ride higher with more oil. either i can't feel it but it felt lower! it flicked better and it turned better!

can i ask what you would expect 130 (i think i have 140) would do?

Per, i'm listening and i do go your way whenever i'm not sure - sometimes i like to follow my 'hunches' so that i can find out for myself.

regards

Taffy

Re: fork rebuild

look it's not really under the fork rebuild heading , or maybe it is ???

but after my 1st decent ride with my upgraded [ rebuilt ] forks
48 springs ,gold valves .apart from the obvious improvement in the working action , i was also amazed at the amount of energy i had left .

the conversion was well worth the mega bux it cost to do :blah5: :blah5:

Re: fork rebuild

Whosaberg, how much do you weigh?

I have .48 fork springs now up from .40, I weigh 245 lbs in gear. I have only ridden in the backyard and dirt road for the moment, to get my arms used to the bike again (still a bit more PT to do) and so far no clue how it's going to be handling on the trail.

Re: fork rebuild

froggy

200 pounds in his alpinestars mate but you gotta remember that he races with no clothes on...

http://www.husaberg.org/modules.php?nam ... pic&t=3908

regards

Taffy

Oh so I should be fine with the 48 also I have realized the bike too goes as "straight as an arrow" at first I thought I had too much air or not enough and nothing is wrong there so I guess it's an improvement.

Jeremy Wilkey himself redid my forks and shock I will believe him.

He tends to advocate stiffer springs too.

By the way I have my springs on eBay right now, I am not holding on to these items, if you are 160 lbs, bought a bike from a fat ******* who had it resprung for himself, and need to go down in spring strength.

I know, I am not supposed to advertise my classy in the forum but I just did it anyway.

Nick I see you went with stiffer springs. I used to weigh just a bit less than you but probably ride the open stuff a bit faster also. What about the forks did you not like. I thought they were very good with only firm bottoming on big landings or g outs. Seemed to work good in the rocks as we got lots of them mixed with the sand here. Did you have your valve stack changed too? How is the back. for me that was the problem area to get it to g out well but not rebound too much then and still have it supple in the rocks. hard to get both. Now on my 05 I think I may try the 48's but the forks work pretty good now and I havent gone through all the clickers yet, let alone fork oil levels and weight.
Its always good to try new stuf and find out just what works good for YOU