WP shock absorber fluid alternatives

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by HellsAlien, Dec 21, 2008.

  1. HellsAlien

    HellsAlien a has-been that never-was

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    Since we're buried in snow & ice here, its time to renew the White Power rear shock fluid.

    Only thing more shocking than the WP shock is the price of KTM shock fluid: $217.00 per 5 liters! That's $43.00 per liter. Even my favorite imported rum costs less than that!:eek1

    So off I went searching for info on alternative fluids: Ocrush, garage, etc. Nothing here popped up. I guess nobody does their own shock work or wants to talk about it much here.

    Specs on WP fluid are few and far between. I found a cross-referance sheet built by Red Line oil that is quite informative:

    Fluid Vis, cSt at 40degC cSt at 100degC V delta T
    WP 5w 24.6 5.1 4.82
    WP 7.5w 34.0 6.5 5.23

    The Red Line suspension fluid equivalents for shock service are:
    ExtraLight 2.5w 9.8 4.0 2.45
    LightWeight 5w 18.4 7.1 2.59

    (sorry, I can't get the horizontal spacing to format right),

    This stuff is $9.29 per 16 oz, less than half the cost of the KTM flavor.
    It is made in USA (Brea, CA, I used to fish there, but we didn't eat 'em!)
    I can get it locally thru normal auto parts distruibution channels.

    The interesting spec is the V delta T values. That is the ratio of viscosity at 40C divided by viscosity at 100C. The less change the better when comparing similar fluids. The Red Line product (at 2.59) shows only about half the change in this ratio vs. the WP oil (at 4.82), meaning the viscosity droops much less vs temperature rise, important in a shock for consistent valving behavior over a wide range of conditions.

    For shocks, viscosity at 100C matters more 'cause they run much hotter than forks, hence the LightWeight 5w looks like the best pick, given my riding loads/speeds/climate. So that is what I'm going to try.

    I'm gonna do this on my 5018 from the 250 EXC first and see how it works as it was weeping at the seals anyway. Same p/n for the oil & seals with my 950A too.

    Anyways, its more fun than shovelling snow! :D
    #1
  2. PowerCell

    PowerCell Manufacture Super Supporter

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    You're spot on with your research. Redline Lght weight is perfect, and don't forget to add the Synergy shock seal while you're in there.
    #2
  3. jsrider

    jsrider Long timer

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    What made you decide to do it? Performance of the shock? Age?
    #3
  4. HellsAlien

    HellsAlien a has-been that never-was

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    PwrC: thanks for the cross-check. It made sense to me. I'll look into the synergy seal, see what they have to say. Thx for the tip on that. I got 5 seasons out of the stock X ring on the 250, but X rings are, well, better than an O ring for dynamic seal, but that's about it.

    jsr; yeah, just a normal renewal. The shock when fresh works great, I'm not gonna mess with the valving at this point. Given the amount of snow and ice we got this week I'll be lucky to ride woods in 3 months! So when I get this one renewed I'll tear into the unit on the 950. They are a bit more work, mainly a hassle to get the spring off, go thru the preload adjustor too.

    I got scrader valves on the gas-side; that makes it way easier to deal with at the white trash tool/technique level I generally practice. Its about a 6 beer job, done correctly!
    #4
  5. FuTAnT

    FuTAnT KTM 990ADV

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    At a punt (reasonably well thought out hopefully) I'd say you're looking at Motorex SD-1 Shock Fluid. Of course if you buy it through KTM you'll pay with an arm, a leg and a few eyes, but buy it through Motorex and you're laughing.

    A quick google revealed the following links:

    http://www.revzilla.com/product/motorex-racing-shock-fluid
    http://www.magicracing.com/Motorex-Racing-Shock-Fluid-5-liters_p_4449.html#

    http://www.motorex.com/index.cfm/fuseaction/show/path/1-418-443-774-1955

    Of course, the motorex site doesn't specify too much more info, but an e-mail etc might get them to reveal the technical data, or some more googling. Hmmrr, I thought Motul did shock oil but I can't seem to find it.

    AHA, I remember now. Maxima.
    http://www.maximausa.com/products/suspension/shockfluid.asp

    A lot of suspension tuners etc use this fluid, particularly the fork fluids. They make nice stuff. Although odd viscosities ... 3wt, 7wt etc. That would be why it's kinda a bit in between I guess. Then again, the tech data doesn't lie, but the claimed weights often do.
    #5
  6. cpmodem

    cpmodem Orange Caveman

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    I use Honda 5wt in the KTM.
    #6
  7. HellsAlien

    HellsAlien a has-been that never-was

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    FuT,
    Yeah, I really like the Motorex product too, I actually think that is the closest to the OEM product. I use that in Showa forks/shocks for my track bike, road bikes and suspensions with parts sliding on aluminum. It produces the least amount of wear/black oxide in the oil of any stuff I've used. But it is problematic to get here.

    CP, the Honda 5W is a good tip, thanks. PM sent FYI.

    Geez, it has snowed another foot here overnight & still coming down! Now 3 feet on the lee side roof.
    #7
  8. crazybrit

    crazybrit Long timer

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    Shovelled your sidewalk yet? Ugh.

    Is there a how-to on servicing the WP shock? Lots of stuff on forks. It seems like it needs a fair amount of special tools. If not, how about stepping upto the plate with a write up and some pics, sounds like you've got nothing but time ......
    #8
  9. HellsAlien

    HellsAlien a has-been that never-was

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    Bring your shovel (& PBR); we can talk!
    #9
  10. LKN4DRT

    LKN4DRT Mended

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    How do you get all the air out?
    #10
  11. HellsAlien

    HellsAlien a has-been that never-was

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    If you mean out of the oil on the working side, I use a filling/bleeding technique that bleeds all air to the top end vent of the assembled shock or to the compression stack port of the shock. There is some science, art/experience & patience to this. It starts at a good shop vise. Lots of oil. Warmer temps than we have today. Good technique stroking the shock rod assembly (can I say that here?) Learn on a Showa/bladder shock, they are simple to deal with compared to a WP unit.

    A modern advanced way is to pull a vacuum on the shock/oil down to about 10mm Hg. This causes dissolved/entrapped air to come to the top. Some shops claim this can double or triple oil service life. Race shops in SoCal are doing this. I have no direct experience with this technique (yet.) But it sounds like a good technique, esp if you have access to a vacuum pump of some sort.

    Hope that helps.
    #11
  12. ridewestKTM

    ridewestKTM Long timer

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    I'm glad to see this thread - I usually just paid the price. Thanks for the research. Got to admit though; that WP shock oil is strange stuff might be worth it in some way.
    #12
  13. rufus

    rufus We're burning daylight...

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    I use mobli 1 synthetic ATF in my 525 KTM. I have used ATF for years in many different bikes. I use it in forks and shocks. Works great. Doesn't seems to break down as fast as most "suspension fluids". Definitely less shock fade. I would rate it between 5 and 10 wt.
    #13
  14. Luke

    Luke GPoET&P

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    The 640 shock uses the same fluid, and Silkolene RSF pro 2.5 wt feels about the same as the original fluid. It is 13.6cSt@40C, 5.83cSt@100C

    I use a handheld vacuum pump when bleeding, it seems to work well. I can loan you my setup if you want, but it'll need a different fitting to work with the bleed port on the 5018.
    #14
  15. HellsAlien

    HellsAlien a has-been that never-was

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    Rufus,
    Thanks for that. I have used synth ATF with good results in forks as well, but I have not used it in shocks. ATF has really good antifoaming properties and good additive package. It keeps car tranny parts from rubbing together for years.

    Are you happy with cold weather performace with ATF in a WP shock, do you notice any difference?

    My "research" shows that ATF has about 2 to 4 times the change in viscosity from 40C to 100C vs the Red Line 5W sauce. But syn ATF is WalMart accessible & priced, a big advantage. Given that the temperature swing on forks is much less than that of a shock, it makes sense that it is suitable for forks. I have seen no unusual wear either. I have found it is as good as Motul 5/7.5 W for use in forks.
    #15
  16. greatnortoni

    greatnortoni Been here awhile

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    You may want to try this;

    [​IMG]

    or this

    [​IMG]

    If you go to the web site it has a lot of the technical info you want.
    I get mine from Sliklube. You can e-mail him sliklube@hotmail.com
    I have had real good results with this product.
    Good luck rebuilding the shock.
    Greatnortoni:rilla
    #16
  17. HellsAlien

    HellsAlien a has-been that never-was

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    Finally, after holidays, a 40 year snow event, I got thru the WP shock rebuilds. Here is a brief summary of events and results:

    The shock for the 950 with 5W RedLine suspension fluid functions good as new, maybe even a bit stiffer than new. I could only get a few miles in at 48 deg F, so the shock never got hot. More "Baja research" is required!

    I started at handbook "sport" settings riding solo, 3/4 full of gas, 200# on the seat; that was way too stiff. Went to standard settings. Better, but still not plush over speed bumps and big rises, and skittish going down steep hills.

    Went softer to 10 clicks out on low speed compr, 1.5 turns out on high speed compr, 14 clicks out on rebound, and 2 or 3 turns in of preload.
    Works good now, slamming around on pavement, steep hills, speed bumps.
    Reminds me of my origional test ride, the sense of control I had, so I am a happy OC asylum rider again!

    Works good enough that now the front feels like crap, way underdamped, but I have softened it a bunch to minimize rim dents. Next I try more damping and preload at the front to balance the bike out.

    Stuff I know now that I didn't know before what I know now:
    1. Shock fluid renewal can be done at home, it requires some tools and skills. If you've done Showa units you could step up to the WP unit.
    2. Minimal for 950, you need spring compressor to suit spring, 24 mm socket for compression valve, skills to put a 1/8" pipe plug thread in the gas cap of the shock.
    3. I put a scrader valve (brass valve stem) in the gas side cap of the shock. It clears the chain, is slightly higher than the top chain roller, I don't think it will be a problem so long as chain is tensioned correctly.
    4. My shock has 35K miles on it, this is 2nd rebuild. This rebuild feels stiffer than the shop rebuild I had done at 16K miles.
    5. Bleeding the body of the 950 shock was easier than expected. There are details to assembly, getting the gas piston positioned right, but it is not rocket science, only model airplane science.
    6. It took most of one 16 oz bottle to do the shock, but I recc you get 2 bottles in case of screwup. I found it on the shelf at D & S Cycle for 8 bux a bottle. Heat the bottle in the sink just prior and bleeding will go fast.
    7. Assessing wear, parts to replace: in my case, in hindsight, I should have replaced the piston rings on the OD of the 2 pistons. Everything else looked really good, there was minimal air in the oil at disassembly, no wear marks on the main barrel, all seals looked/felt good. But it works so good now I'm just gonna ride the crap out of it again, knowing I can R & R the thing in a half-day next time.
    Secret knowledge stuff you will only find on OC/ADV rider: I found that it is possible to get 10 bar pressure (150 psi) from a standard argon gas supply regulator on a common MIG welder. It cost me my flowgage to learn this (I knew better!), but they are cheap enough to replace. Next time I valve off the flow gage prior to gassing up a shock.

    I cannot reccomend using air for this shock, it needs dry inert gas because of the dynamic seal on the oil/gas piston.

    I can recommend 5w RedLine suspension fluid for the WP shock, it is a good product at a reasonable price.

    Thotz for next time:
    Consider only 8 bar pressure instead of 10 bar and use Synergy shaft seal for better compliance of the shock. Have any of you inmates done that?

    If there is enough interest I could Frankenstien on crazybrits shock and doc the details better for H.O.W., but baja comes first, ole!
    #17
  18. cpmodem

    cpmodem Orange Caveman

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    Great write-up! I'll go ahead and upload it as is to the HOW, and you can fine tune it in this thread as you wish. Just shoot me a PM when you do, so I can make the updates.
    Thanks for following through.
    #18
  19. rufus

    rufus We're burning daylight...

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    Years ago I used to race hare scrambles a lot. I am a big guy and ride hard. Shock fade was a terrible problem for me. ATF does not fade like typical suspension fluid. When i was racing a lot i could feel the shock going away after 2 or 3 races. ( About 1 hour into any ride and the damping went south) 5 races and it was nearly unrideable for me. ATF would last me 4 or 5 times as long. Nowadays I trail ride and do DS rides. I only have to change my suspension fluids about every 2 or 3 years.

    ATF is definitely stiffer in cold weather. Suspension is harsher until it warms up. Usually 5 to 10 miles for me.

    With regular shock fluid the oil always came out black and grungy looking. ATF comes out very clean. I have about 14,000 miles on my 525 and the suspension internals look like new.

    The first time i changed the fork and shock oil in my 525 KTM -2003 model- I used amsoil. It was harsh on small stuff and faded guickly. 6 or 8 rides and I went back to ATF.

    I do have my comp and rebound , set softer with ATF.

    I am picky about my suspension. I will use what works best for me. If there was a $100 a bottle fluid that worked better I would use it. I have tried several different ATF fluids ( and many many susp. fluids)over the years. Mobil 1 synthetic ATF is what works the best for me.
    #19
  20. ganshert

    ganshert not sleeping

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    5018 bleed port is 1/8 BSPT (British Standard Pipe Thread) :thumb

    McMaster Carr has several fittings that will work. I use a pipe nipple that takes it to 1/8 NPT and then go to a hose for applying vacuum.
    #20