shock tuning for enduros

Lew makes a good point re pressure loss during chuck removal.

I used to use a straight (not 90deg.) fitting and would experience approx 10PSI loss during chuck removal- and I was leaving the N2 supply flowing during removal to minimise losses/achieve more consistent fills.

I believe the correct chucks like listed previously (the no loss types) are by far the best option for Scrader use..

I just measure the pressure after charging and get the hang of how much extra to put in, granted the measuring drops the pressure too but its easy to get the hang of it.

the real test of the pressure is in riding anyway........

regards

personally i have no doubt that you must keep the pressure at 175lb while you close the schrader or indeed the OEM screw.

regards

Taffy

Many a good link on valve stuff. Thanks.

Taffy, 175 pounds per square inch? Thats 12 bar, I thought they specified 10 bar (145 pounds)...

The -98 had linkage, the -99 had no linkage and PDS and was maybe not the best the world had seen, you don't think it improved at all in the -00?

It's pointless then?, to do anything but to pour in new oil, bleed, charge and put it back on the bike.

Regards

i can't even remember which bike you have!!!!

but which shock have you got? i don't know anything about the pre-2001 huseys.

i have this shock which i stripped for a look-see and could probably send you everything by post. don't know anyone going stateside at present.

but it's a very old shock with even the basics being superceded. i have a word doc which i have compiled. it holds info on the changes made throughout the 2001+ period to the WP PDS shock.

but if you have the same leverage ratios and can fit a post '03 shock then you'll be relatively up-to-date.

regards

Taffy

The gas charging problem solved, used the inner tube Shrader valve and Loc-Tited it in using low nuts on each side of the cap as showed before. The shrader does not stick out at all from its recess in the cap. The side claw air chuck does not reach down in the recess so a shrader valve extension is used at the time of charging, the side claw air chuck is then applied to the extension as if it had been the shrader valve itself. When the gas charge is done i just release the side claw and that spits off the hose abrubtly, not losing any of the charge.The shrader valve extension is then removed and a cap is put on the shrader valve to protect it and to make sure it will not leak.
To solve the potential hose release discharge that you guys warned me about, the inner end of the shrader valve was threaded with a M5 tap so that a pilot jet from the Dellorto carb could be used as a restriction. The idea being that when you remove the hose the amount of gas being able to escape would be negligible through the pilot jet. When testing it it worked very well. Then I saw the original stupid WP nitrogen screw laying around, the one letting the nitrogen seep through the threads, that gave me the idea to use an ordinary screw instead of the pilot jet. Said and done, an allen headed M5 x 6 mm screw was scored with a hacksaw on the contact surface of the head so it would not seal when tightened. The charge must now pass through the threads just like with the silly WP screw. The fill is now so slow it does not differ much from filling a tyre.

What I did to the shock was to put the shims back, filled oil and charged the accumulator, must get a reference to see where to go from there, if doing anything at all.

Oil used is a mix of 2 parts Golden Spectro SPL Ultra Light and 1 part SPL Very Light. The viscosity should be close to viscosity grade 15 cSt (75 seconds Saybolt).
With a VI of almost 400 it should be at least as temperature tolerant as any shock oil.

Regards.

08 650 shock stacks stock with "straight rate" 8.4- 250

primary comp
6x44x0.25
2x42x0.25
40x0.2
38x0.2
36x0.2
34x0.2
32x0.2
30x0.2
20x0.3

primary rebound

2x36x0.2
28x0.15
34 x0.2
32x0.2
28x0.2
26x0.2
20x0.3
3x23x0.3
23x2.0

secondary comp

4x40x0.25
32x0.2
20x0.3

reb

36x0.2
34
32
30
20x0.3
21x1.0

nut

comp adjuster
22 x0.25
20x0.25
18x0.25
16x0.25
14x0.25
9.5x0.3

seems pretty normal but too stiff in general when compared to front. teraflex tyre is very stiff too so particulary needs less HS.

testing a "straight rate" 8.4 spring at 20mm gives rate C1 approx 6.6 so its behaving like a PDS 0 at C1 very roughly speaking.

ground down the OD of 3 coils til the C1 rate was approx 5.5.

now a PDS minus 1 or something. very nice could go more but will try to soften with damping for now.

valve is a now shrader even shorter than smorgys ! ha some men be shorter than others.

regards

bushy

terry hay did it another way. his attitude was that the progressive is only that because the coils started to touch/bind at the top/bottom (or wherever), so he ground a flat where they were due to touch. this delayed the progressive till later.

his argument was that a pregressive works over too large an area. 8.8-10.5 would be 8.8 to 9.8 i think in his opinion (which is a very good opinion!) why not call him for advice?

if you PM me your email address we can compare your actual shims to the one quoted to me by the factory boys.

regards

Taffy

Ha! mine is so short that I have to use an extension at the time of use or I can't use it!
I bet you cheat by having only one nut...

if i had the time i'd ask you to measure the stuff in the shock. as in length of rods etc. i believe that they have shortened the shock in '04/'05 time so as usual we are on about different shocks!

regards

Taffy

yes only one nut and a very short protrusion and now taffy wants me to go measuring me rod!

all necesitates the use a very long and shiny brass extension

will do some quick measurisiering and take some pics the needle is of most interest I would think, cant really get down in there though. someone :wink: may have proper dimensions of an 08 needle.

regards

removed 3x44 and 1x42 from primary comp stack

I could only get Bel ray HVI 3wt here, 11Cst @ 40 deg and VI 300.

charged to 150psi. the spring preload required for the sag I like is increased, no way of measuring it but I guess the shock had 170-180psi in it origionally. spent a lot of time making sure the shock was bled properly used vac pump at end, pretty sure no air is in oil.

as an easier improvement I could have removed the resovoir cap with the shock still in the bike, converted to shrader and correctly charged to 150Psi, that would probably have improved things a great deal.

My old yz400 that wouldn't turn had a similar problem in that its bladder pressure was 90psi from new. increasing to 130psi mean't I could get a good sag set up without too much prelaod on the spring, bike turned better without being harsh.

overall results on the WP shock are a step in the right direction for me and this tyre at least. comp adjusters make more sense and are in mid of range, rebound adjuster also in mid of range without making LS compression too stiff. softening the shock eased the load on the forks making life easier for them in some situations, I can soften them a bit on HS now too, I hope.

Taffy i will Pm you the rod dimensions etc they are very rough, I will do it properly next time, was just in a bit of a hurry to ride.

regards

175 is what they come with i believe and i would stick to that?

regards

Taffy

Taffy said:

175 is what they come with i believe and i would stick to that?

regards

Taffy

Click to expand...

I use 150. The lower you go the better up to a point...then bad **** happens. :roll:

Taffy said:

175 is what they come with i believe and i would stick to that?

regards

Taffy

Click to expand...

depending on the number of Ms/HS hits you need your bike to absorb, the pressure needs to be higher.

did some mucking about and played with clcikers a lot.

with 120psi I need the LS comp full in and still get total loss of rebound after about 3 full strokes at speed.

150 handles about 5 before rebound deteriorates
160 handles about 6 and is better but rebound still deteriorates

175 is very safe and I'm pretty happy with it. its harsher initially from extra pressure on the seal and the comp adjuster but I need the bike to handle a lot of full strokes at speed in case I get into trouble in 6th or if i forget where I am on a whoop trail. total loss of rebound in the middle of some big bumps is not good for control.

reason is that the pressure required to prevent cavitation is much higher when the second piston starts to work like at the end of a full stroke. higher pressure also helps refill the main shock body. repeated hits agrivate the oil and you end up with a bubbly quivering mess for a shock. well at least that matches the stock forks.

not sure that "woods" or most enduro riders would need more than 150 but ive never seen a "woods".

regards

Bushie

bushie i think we need you to get doc privilages to upgrade our suspension section. i haven't got a clue what you are on about half the time but i can't fault your enthusiasm sir!

BTW, i stuck a sh... load of stuff in the rear suspension last night including photos of the bleed and pressure gear i have acquired. if you want anything like it have a word with drehwurm.

regards

Taffy

by jezzzzz , i've been just watching the 1st round of the w.e.c and mate some of those blokes on *********** sus (ktm husaberg) are doing just as good as the ones on jap sus.
is *********** really that bad bushy? or is the factory boys on ktm/husaberg on different *********** shocks than the rest of us?
by cricky mate , they give em a fair work out?
..weed..

Hi weed,

I say all of the above.

seriously though they have the benefit of very good tuning and fancy needles and a wide selection of springs and oil. FOR EVERY SPECIFIC EVENT. They may also be running a wp traks or trak or something shock that is roumered to match the ttx or even just an ohlins copy WP SX shock.

a bone stock KXF450 from 06,07 or an RMZ450 handles high speed deep sand whoops very well with no tuning other than prelaod and clicker adjustments, a WP 2 piston enduro shock in any stock design form does not. WEC is not full of these whoops but my riding area is. so horses for courses I guess.

the WP PDS 2 piston enduro shock just isn't very versatile. It can be tuned good ennough for a specific situation but can't be adjusted easilly to another without a big revalve job. their SX shocks with the ohlins 1/1/2 piston design are a lot nicer.

only way to see where I'm comming from is to pull one apart, have a go tuning it and see what happens. the 2 piston/needle design is rediculous. to improve or change it costs $$$$$$$ and look at the plumbing Taffys got hold of to refil the thing.

ohlins TTX is awesomely easy to change shims, bleed, refil, tune etc , I kid you not. its still not a link rear but its another world of performance above the WP clown tube damper.

the WEC riders are very good at what they do and able to adapt for and work around shortfalls in the suspension. are we that good? don't think so.

anyone wanna buy my old WP shock? list price new is around $2400 AUS I think.

regards
Bushie

Geez Bushie, whaddaya do for a job? or IS IT suspension??

sounds like you are serious about good suspenders. Steve talked to me at the force ride, and the image he portrayed about before and after a proper suspension tuning session, the likes of Frank Pons was awesome, I know this should probably be the first point of tuning before power and other stuff, but suckers like me have trouble with suspension adaption.

a bit more trial and error and maybe some progress will be made on my setup (when I'm riding again and have some spare time).

Azza.

yeah im a fussy bugger I get paid to be fussy your onto that

as with all things, if your happy with the shock leave it alone.

azza if your not riding you must be working hard. :cry: If you come over for a beer with your bike I'll pull some shims off one piston for you and stick em on the other. why not send your shock to frank? it'l make setting up the handling far more enjoyable and may even make more sense. the forks are a bit easier to muck with ive seen your gallery you'd be able to handle it.

regards
Bushie