790 Adventure R Suspension Mods

Discussion in 'Parallel World (790/890)' started by windblown101, Jul 5, 2019.

  1. WI-790R

    WI-790R Been here awhile

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    additional pics:
    8CA348DA-E6B2-4F7F-869C-5406B5917135.jpeg ED24F54C-F496-4E0A-879F-AC131EC4825B.jpeg 06ABCE89-A11E-4622-BA51-7EDAE18120FC.jpeg 8E25B353-8FE1-41A5-8DD7-083D32BEBB74.jpeg F6E2D30B-94CB-44D8-A660-130E924D2A3C.jpeg 46EE9B07-C979-4DC5-BD4B-DE7BCE9A42FD.jpeg

    Torque is still waiting for me to supply spring rate info, for the Hyperpro spring I have, sold by Touratech in the 30mm lowering kit. I wasn’t readily able to get that data, so I plan to collect my own. I am building a spring tester, a hydraulic version using a pressure transducer and digital readout. What force range should my tester measure? The pressure transducer is rated 0-1600psi. So I will size the piston/cylinder to equate to the force range needed. What I may not have access to, is a calibrated load cell that I’d use as a reference to calibrate my tester.

    I’m hoping with advice from those that know these things, to make the bike less harsh on square edged holes at highway speed. I realize the lowering of the bike is giving up some travel. I also realize that the suspension performance can’t be optimized for both me alone on the bike (180lbs), and with my wife as passenger (130lbs?). Thank you in advance for any advice that’s offered.

    Below are pics of the vacuum bleeder and 10M-1.0 adapter I made.

    A4FA5884-B572-4694-9431-15B9178CBC3D.jpeg E42A7D2F-B740-42EE-A1C5-C1F6FC8D0B1D.jpeg

    Thanks to kubcat for helping me better understand how to manipulate pics within a post!
  2. kubcat

    kubcat Long timer Supporter

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    If you go back to you posts and click edit on a desktop browser, you should see a whole lotta these (I removed the starting and ending brackets - "[" and "]" so you could see the notations)
    ATTACH=full]2611790[/ATTACH
    ATTACH=full]2611791[/ATTACH

    Mixed with your typed text. Just delete the duplicates, and move the ones you want to keep to different parts of your text using cut/paste...
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  3. WI-790R

    WI-790R Been here awhile

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    kubcat,

    thanks for the tips. I think I've got it.
  4. Torque

    Torque Been here awhile

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    Regarding moving the secondary piston. I would ride the bike first. Yes we have run into situations where the secondary piston on a lowered bike does create harshness. The bikes that we realized this on were lowered quite a bit and they were smaller WP bikes. With the weight of the big bike you might be fine.
    WI-790R and AdvRonski like this.
  5. David_Moen

    David_Moen Long timer Supporter

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    How about converting to a bladder reservoir? I've had that done on a couple PDS dirt bikes in the past, made a very considerable difference in small bump compliance.
    WI-790R likes this.
  6. David_Moen

    David_Moen Long timer Supporter

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    Who's your "local guy"? Ian at Rider's Edge?

  7. WI-790R

    WI-790R Been here awhile

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    Torque,

    I appreciate your input. I enjoy learning new things and can't help myself but to fabricate tools that I'm likely to not use often. But I am not experienced in the art of shock tuning, so don't laugh at me too hard..... I did place an order for a guess at shims. I ordered shims of lesser thickness, same diameter, based on a rule-of-thumb I'd read about the relationship being the ratio of thicknesses cubed. I was shooting for a reduction of compression damping from low speed to high speed of 25 to about 50 or 60% respectively, on both the primary and secondary pistons. Am I way off base? The shims were first ordered Sunday evening from Sdi; they have not shipped yet however. What caught my attention about their site, is that I could order shims individually rather than in lots of 10-20.

    I have the spring tester operational, although have not found a reference to check its calibration against. If I am to believe the pressure sensor accuracy spec, then my numbers should be very good. It's just that the sensor is an unbranded one from ebay that only cost $27. I'm an engineer in the circuit design world, and question a component that advertises +/-0.5% and costs so little. Maybe it is that good.

    This is what I measure on the Hyperpro 30mm "lowering" spring.
    Free length 205.6mm
    compressed 10mm 61.5Kg
    20 136.2
    30 217.6
    40 302.3
    50 392.3
    60 491.9
    70 598.2
    80 713.6

    With me on the bike, I believe that spring to be compressed about 38mm. I have not yet put the data in Excel to graph rate vs travel, etc.

    I measured my stock spring. Those readings showed a mostly linear rate of about 9.5Kg/mm. Is that spring said to be nominally 9.8? But I'd like to remeasure that one. I had a bit of binding of a coil against the clamp I used to temporarily hold the LCD scale on the tester. The red display in the pic is scaled in lbs by the way.
    spring tester.jpg
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  8. Torque

    Torque Been here awhile

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    Ok mad scientist. Just finished a 12hr day and saw your thread and had to smile. I don't want to think any more, but.
    The spring with those numbers is a good spring. Nice steady increase in rate is most times the right recipe. The Eibach springs for instance are like a switch from light to full heavy early in the stroke.
    The rate of your spring is way light but if your not bottoming so be it. Too light a spring usually introduces harshness. Variable rate less so but its pretty light plus the secondary bottoming, it is a tangled web we weave. Not sure how to analyze this. Harshness from spring or secondary bottoming cone. I think both. I just kinda do what works and this just seems to go against what I have found works. Get into your shock and shorten it with a spacer. Get a proper spring and I will give you a stack to play with. I wish I could tell all the DIY folks the stacks but the other tuners are a watching. I will walk you through the process of building the shock long as you have some time. My agenda, Baja 1000, Vet nationals, EnduroCross, all in the garage, plus the regular guys looking for the holy grail. Be patient.
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  9. braaap!

    braaap! Long timer Supporter

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    Plus there’ll be lightning and cries of ‘It Lives’...

    You crazy Mad Scientists... Watching and waiting. :lurk
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  10. WI-790R

    WI-790R Been here awhile

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    I'll take that title as a compliment! Yes, I'll gladly buy the spring you recommend, and I understand you are busy. The riding season here in West-central Wisconsin is about over I think so really, I have months before I can ride the bike much. I'm 59 yrs old but the kid in me want's to fix it now of course. We've had snow on the ground a couple times now, but it's supposed to get back in to the 50s next week. I'll put the bike back together with some guess at mods and hopefully ride it a bit to see the result.

    At my age there's a limit I suppose in how hard I could pound rough trail, if I had access to such conditions. During the winter, if we're blessed with enough snow, I do enjoy rough snowmobile trails and ride a machine that feels better the harder the suspension is worked. That said, I'd like the bike to feel less harsh, but wouldn't want to be such a marshmallow that I'd run out of suspension at medium speed on a rough trail should I find one.

    The approx. spring rate at the amount of compression when I'm on the bike is about 8.4Kg/mm (based on the measurements I got). Is that what you mean by "way light"? or were you looking at the initial rate when barely compressed?

    upload_2020-10-29_13-3-4.png
  11. WI-790R

    WI-790R Been here awhile

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    Is it the stiction of the floating piston that made it less compliant than the bladder?
  12. Torque

    Torque Been here awhile

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    Overall rate.
    On a heavy bike will the bladder make a noticeable diff? When we switched to bladder on WP 300 race bike we did so because bladder held 20cc more fluid. The rider noted that he felt a mild improvement in initial hit compliance compared to other mods. So small bike bladder install lets say makes a 4% improvement in initial hit compliance. Not so sure that would be noticeable on big bike. Also the bladder piston we replaced was in the 60mm size range. WPs larger od reservoir. They have noticeably more stiction than the smaller diameter reservoirs.
  13. WI-790R

    WI-790R Been here awhile

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    Just got back from a ride, all paved road unfortunately. I put the shock back together yesterday and was curious how it would ride with my novice mods. Either the road got smoother or the shock is more compliant. I’d like a section of whoops to ride through, to see if I’ve crippled the shock in areas my road ride wouldn’t show. I had the clickers and HS adjustment set to the standard positions. There’s still a bit of harshness on holes and such, but it feels closer to the EXC-F now.

    Torque, you mentioned the harshness could be from the spring, the secondary piston (since I’m lowered), or both. I know you advised riding the bike first before moving the piston, but since I don’t yet have a different spring, I went ahead with the piston relocation. Have lathe, must turn.........haha. So changed more than one variable.

    I moved it 9mm and installed my first ever guess at shim mods. I see the repair manual specs like 21lbft on the rod nut. That felt like too much to me. I chickened out and went with less than that & used a bit of medium strenght loctite. 3744AB14-B0D0-40B6-9394-7547A4E59260.jpeg 18F3F891-1E6D-4C91-86AA-5D3AD0133682.jpeg I measured the holes in the secondary piston, computing those 6 hole’s area to that piston area vs the area of the compression holes in the main piston relative to that piston area. The holes on secondary would have to be larger to match the percentage of the primary holes. I suppose WP wanted it that way. Do you think that’s a problem?
  14. Torque

    Torque Been here awhile

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    Excuse me for not reading back on your mods. Have you drilled a bleed hole in your main piston?
  15. WI-790R

    WI-790R Been here awhile

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    I haven’t drilled a hole yet. I think you mentioned 1.2mm? I see dimples in the piston. Is that were you drill a hole? I didn’t know how many things I should change at once. I think I recall you or someone, mentioning a set screw could be used to close that hole if needed. Makes sense to me, just loctite it in there?
  16. Torque

    Torque Been here awhile

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    First order of business in my opinion is a 1mm or 1.2mm hole in the piston. This will reduce the cavitation, help initial hit, get the back wheel to the ground faster for more traction and lets see, I will think of something else.
    Some of the wp bikes come from the factory that way. I was told when these shocks fail they drill a bleed. Is that true ? But that is what I was told by a WP certifiable shop. Also if your going to stick with that spring your going to need more hold up damping as a band aid. Beef up your compression valve stack. That reminds me weak spring maybe a bleed is not good. Have to test to see. You can easily just epoxy the piston bleed. Do it all the time. I put the piston in aluminum vice jaws or plastic or wood whatever works for you and punch and drill right into one of the ports.
  17. Teamrat

    Teamrat Adventurer

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    OK this is a belated review of Torque's suspension work he undertook on my standard 790R suspenders.
    My brief to him was remove the harshness and also factor in that I often pillion with saddle bags.

    So far we are just entering riding season and haven't hit the high country rocky trails here yet in NZ but have managed a few back roads and some of the more challenging tracks. The difference is plainly night and day from what the standard setup was like. A dual rate spring and revalve on the rear and lighter front spring along with the revalve at the front converting the separate comp and rebound setup to an external adjustable rebound setup on both legs has been awesome.
    The simple of it all is that no longer can a sneaky square edged pothole nailed at pace punish rider and pillion, it now nicely soaks the harshness out of the hit and lets you get on with it.

    I think a lot of folk also don't realize the importance of getting the bike sprung well, letting it sit up on the spring and having the damping set to control that spring. The spring rates Torque has used in this setup are spot on for how we ride, another noticeable change has been that the steering damper no longer earns its keep as it seems more stable in most situations so far.
    Will need to check the current sag as of yet all tuning has been seat of pants.

    WI-790R I have a 1.2mm hole in the shock piston and there has been some shim shuffling on the comp and rebound stacks which saw change in relationship of the secondary piston and its section in the shock body so this was spaced to retain that relationship by modifying spacer between rebound and secondary comp stack to suit, working ok so far.

    So thanks Torque from a happy rider and pillion.
  18. Torque

    Torque Been here awhile

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    Thanks Teamrat. I do appreciate the feedback.
    Regarding WI-790 the spring is problem #1
    We have been private messaging although maybe we should do that for all to see if he is willing.
  19. WI-790R

    WI-790R Been here awhile

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    Torque, certainly. By reading my shim stack guesses, others can learn what not to do!
  20. Torque

    Torque Been here awhile

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    I will try to find time to do a quick read on what we have addressed this evening. Maybe?