Another CRF1000L fork thread!! Reg vs Adv Sport forks.

Discussion in 'Japanese polycylindered adventure bikes' started by Motociclo, Oct 22, 2018.

  1. yokesman

    yokesman Long timer

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    My AT is going in for the fuel gage, FI to morrow. After that for sale. I have a project bike i enjoy more but never put any money into, besides from what sales I got from the original parts. xr650r forks on a suzuji gladius. All this brought me to this conclusion ,the last comment by Jeff solidified. Besides not enjoying the ride, bought several bikes in the past with the same conclusion, I like a bike with some character.
  2. Junglejeff1

    Junglejeff1 Long timer

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    I purchased bike to ride wifey around.If she ever loses interest it will be sold next day.I would celebrate by buying a TRS GOLD to replace my gas gas. Screenshot_20190723-101633_Samsung Internet.jpg
  3. Capt CF

    Capt CF Pontificating Nobody

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    Just throw a Russell Day Long on there and you and the wife should be good to go.
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  4. Motociclo

    Motociclo Long timer

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    Finally stripped down forks off 800xc Tiger.
    These are a 45mm fork, with about 220mm of travel, like AT. They were on the 2012 to 2014 models.
    I have mentioned before about seals and bushes are same between AT and 800xc, but thats where it ends.
    I was hoping the outers would be an option, but no, sadly not.

    To start, the AT tubes are 55mm longer.
    The triple mount areas are close, AT 5mm longer at about 285mm from top of tube to base of triple clamp area.
    I never bothered measuring OD after i saw length difference.
    The damper tube mostly identical to AT. There is no adjustement on spring, comp or rebound.
    Can be revalved easily enough though. Same as AT. Same oil lock also.
    In below pic, you will notice the empty damper tube is damaged from trying to separate the tube. I couldn't. Thus one is off AT. Tried to separate 2 pieces of damper tube as alternative to removing oil lock. Didn't work.

    20190804_122439.jpg

    The lower legs are vastly different.
    AT, on left, much longer.
    20190804_085055.jpg

    Now, the interesting thing.
    Anodising was worn through on both legs.
    One was in typical circle pattern, about 160mm from top, the other had a wear in a strip running the stroke travel. I know the owner, he doesn't beat onthisbike either. 35k km on these forks.
    They have similar stroke to AT, but shorter outers. This would lead me to think the XC outers would be inherently stiffer, but the wear is there. Flex the likely culprit. Though i can't explain wear in the tube where it runs the stroke length. Odd. Haven't seen this before.

    20190804_122631.jpg

    My thoughts in anodising is starting to change a little.
    Type 3 hard anodising and Kashima are marketed as wear resistant coatings. They work to a degree. My Kashima wore through on stock AT outers. I noticed it at 20k km on recoat. By 30k km, wear was significant. It isn't flogged hard off road either.
    This coating is typically only 0.05mm thick. not much.
    Something has to give, when up to 10kg/cm2 of force is put on it. Compound that with flexy tubes. Something has to wear.
    The odd thing, I have seen consistently, the slide bush has had no wear, even when anodising has long departed. Mine for example, 30k km on 2 different sets of bushes, zero measurable wear. 1st set on stock tubes, 2nd set fitted when i got tubes Kashima coated. 60k km, I have replace wear parts that last longer than the coating. Quite funny i feel.
    I have a few sets of worn AT tubes, that i have aquired, to play with.
    ID is pretty consistant. But all show the same 0.05mm difference where anodising wore through. I use a bore guage to measure.

    The stock AT outers are flexy, i feel this is main reason for harsh feeling on harder hits. I have seen how much they flex.
    Anodising, particularly on most forks is cosmetic. I think it is almost inevitable that it will wear. But, if in general, the performance doesn't degrade, then with or with out anodising, it doesn't matter.
    Alloy dilution in oil makes it ugly. Just service your forks and keep fresh oil. 10k km is a sensible interval. 20k km, this would be absolute upper limit.
    I have spent a lot of coin and time looking for solutions to hopefully reduce/stop anodising wear.
    I use ATAS outers, they are less flexy than reg AT, but still flex a little. They are still a good option no less.
    In time, i bet, they will wear the Kashima through. I am not going to fret it.
    Just ride, service and enjoy.

    I have just learnt about the new Ohlins forks are starting to lose anodising.
    Disappointing, yes. But they are still a far superior fork than the Showa units.


    Edit,
    As usual have spent to much time researching stuff. This time just on anodising.
    Like I mentioned earlier in post, Type 3 and Kashima are marketed as high wear products, which they are. Eventually, I found this small bit of info on a Aussie site.
    It is the second last FAQ.

    https://www.decorativeimaging.com.au/protective-coatings/hard-anodising/

    What I take from this, is anodising wear in fork tubes is certainly inevitable.
    They flex/bend and create a high pressure point where bush meets tube.
    As tough as these coatings are, this enviroment my not be best suited.
    That's just my interpretation.
    Fork tube material, not sure, but believe 6000 or 7000 series aluminium.
    Specifically, 6061 or 7075. Can't find anything rock solid to confirm this, again, just what I think. It seems to be pretty tough without anodising. Anodising used mainly forcorrosion resistance. With oil and a teflon fork bush, wear on alloy surface is likely very minimal.
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  5. Amphib

    Amphib A mind is like a parachute....

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    Great post motociclo, thank you for sharing this info.
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  6. ski-line900

    ski-line900 Been here awhile Supporter

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    Dang
  7. HerrDeacon

    HerrDeacon Been here awhile

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    I agree, this is the route I'm taking with my AT. I'll service them regularly but even if they show wear I'll continue to use until I can actually feel something when riding.

    Thanks for the great post, appreciate your time and effort investigating this.
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  8. RustySpokes

    RustySpokes Ordinary average guy Supporter

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    Getting ready to order ATAS uppers and lowers to hopefully fix my forks for the foreseeable future. Anything wrong with using new stock bushings or is there something else I should consider?
  9. Junglejeff1

    Junglejeff1 Long timer

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    I use race tech ones and honestly not any different.The rt one were cheaper bit excellent quality and had them in 3 days.
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  10. dadouzzu

    dadouzzu Adventurer

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    Hi, i have had the same anodizing wear with a ducati showa: first set worn in 30kkm and the second in 6kkm.
    On both set the stiction in sag measurement was 15 to 20mm.
    I found that most of the wear in the bushing is on the edge like if it was acting like a chisel on the outer tube.
    On the third set i chamfer the bushing land so it can follow the flex.
    Next season i will check if it works.

    Motociclo, did you have some pics of your upper bushing land?
    Is it cilindric?
    Inner tube thickness?
    Sticktion?

    Attached Files:

  11. Motociclo

    Motociclo Long timer

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    I did think at one point the edge of bush maybe acting like a chisel on outer tube. This was more related to how much clearance there was bush/tube.
    I haven't and won't mod were bush locates any more than adding a shin to reduce bush/tube clearance. Wouldn't want to reduce material in this area.

    Typical clearance, 0.12 to 0.18mm seems to be accepted norm. My stock AT tubes had 0.25mm, and slopped around terribly.
    I shimmed stock tubes, but not my ATAS setup. Clearance was/is 0.15mm.

    Stiction was minimal in stock AT tubes with ano wear. Could only just feel.

    Flex plays its part in ano lose. My views have changed after abit of research. Ano wear is pretty much inevitable.

    I serviced a set of 800xc forks recently, 30k km, ano worn both legs, no stiction. These also Showa.
  12. dadouzzu

    dadouzzu Adventurer

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    I don't know if reshaping the bushing land is the solution but i haven't increase the clearance. Some example..
    Barrel shape, central ribs, racetech solution to sticktion horrible 89' cr250 forks with cylindrical bush lands
    IMG_7365-M.jpg 2015-09-30 18.25.29.jpg s-l640.jpg

    With these type of lands the bushing can't act as chisel, even with a lot of slop

    O.t. did you use restakor for valving?

    Thanks
  13. Motociclo

    Motociclo Long timer

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    I interpreted what you said as reshaping bush seat, but guessing more so the bush it self. Act like a spherical bearing if sorts.

    I use restackor and a lot of testing.
    It works well. Input data needs to be pretty good. Once sorted, out puts some good info.
  14. dadouzzu

    dadouzzu Adventurer

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    Yes, i reshaped only the lands to try to act as a spherical bearing and tolerate some flex. We will se if it is good...
    The clearance with new bush was 0.10mm
    20190616_135936.jpg
    I think that is not good to have worn ano because all the shavings also affect damping maybe wearing cartrige tube, piston band, piston/shim surface, etc, and also in my case affect sticktion and scratch the stankions.

    Maybe that honda and also ducati asked to showa a cheap fork and they do a fork with cheap bush lands ?

    Did you have some pic of the lands in the fork that you inspected?
    Someone have see an ohlins?
  15. Motociclo

    Motociclo Long timer

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    Never good to have any loose material in fork oil, it is just how it is. Regular service and wear to all other parts minimised.
    I have never bothered with pics of bush mount area.
  16. Lost Cartographer

    Lost Cartographer Been here awhile Super Supporter

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    After 3000 miles on my ATAS uppers + lowers there was significantly more clearance than when I first installed them.

    I shimmed the bushings when I put things back together.

    Same racetech slipper bushings.

    I cut the shims to ride down the center of the RT bushings, allowing them to rock even more than before. Similar concept to what dadouzzu did.

    Didn't take any clearance measurements this time, as I was in a rush, but I can still feel a bit more slop than I would like.
  17. dadouzzu

    dadouzzu Adventurer

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    Lost Cartographer, how do you fixed the shim to not move up or down?

    I have also play with shims.
    On the previous set there was 0.15mm of slop.
    I tried 0.1 and 0.05 (0.025 and 0.05 shim)

    I found no difference in sticktion but maybe some binding on bump with 0.05 and 0.1.

    I don't have a bore gauge so i measured the slop with a dial gauge.
    An example for lower, but for upper is the same setup
    20190615_151507.jpg

    Did you measured the sticktion (L2-L3)?
    https://racetech.com/page/title/Sag
  18. Lost Cartographer

    Lost Cartographer Been here awhile Super Supporter

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    Here's the racetech bushing - it's just a stock bushing with a couple of grooves cut into it to allow it to rock.

    IMG_20190603_110421~01_med.jpg


    Here is the template of the shim - installed it so the "tall" sections are on the left and right side of the fork tube. That allows it to rock fore-aft the maximum amount.

    IMG_20190606_075359_med.jpg

    IMG_20190606_080603_med.jpg
  19. Lost Cartographer

    Lost Cartographer Been here awhile Super Supporter

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    Did a bunch of changes this past round: another revalve, shims behind the upper bushing, tapered the compression adjuster needle, and relocated the spring to the top of the damper rod.

    Looking at the design of these Showa open chamber forks it seems to me that the upper bushing would get a lot less lubrication than the WP open chamber forks on my KTMs:
    - The spring is totally submerged in oil in the Showa design. The spring spacer sits on top of the spring.
    - Only the spring spacer plunges into the oil and comes back out. I'm not sure how much oil it carries with it.
    - On the WP forks the spring is constantly plunging into the oil and coming back out, bringing oil with it that would splash lube the upper bushing.
    - On the Showa forks the "damper rod pisser" (the hole in the damper rod shaft that always pisses oil on the shop floor when you are bleeding the forks) is totally within the spring spacer. That means that the oil that sprays out of it when the fork actuates is trapped inside the spring spacer, then runs down the inside of the spring spacer to the oil bath below. At no point does that oil get out to lube the upper bushing.

    I put the steel spacer in the bottom of the fork, machined a centering ring to keep it and the bottom of the fork spring centered, made a centering piece that goes on the damper rod shaft above the pisser hole, then made top cap spacer + centering piece. Now the spring drags a bunch of oil upwards out of the oil bath, and the pisser hole sprays thru the spring onto the upper tube, hopefully adding additional lube.

    Stock layout - the pisser hole is within the spring spacer:

    stocklayout.jpg


    New layout - the spring is now under the fork cap, and the pisser hole can spray oil thru the spring onto the outer tube. Note that in this photo the inner spring spacer is in the wrong spot, it actually sits right above the pisser hole (to the right of where it is shown):

    newlayout.jpg


    How does it work? Dunno yet.

    I have only ridden it around the neighborhood, but it definitely moves better on small road inputs. On visually smooth roads (worn blacktop that has small ripples) it doesn't 'copy' the road surface like it did before. Could be the additional oil lubrication, but it could also be the valving and/or the bushing shims. Since I changed a bunch of things at once I really can't say.

    I need to spend a whole day out riding some rougher roads (frost heaves and expansion cracks) and also hit some off road trails to get deep into the suspension. It's been icy up in the mountains, so it'll be a while before the bike gets a good test run.


    Also here is the tapered compression adjustment needle. Original on the left, modified on the right.

    All dimensions VERY approximate:

    IMG_20191218_155656~01.jpg I
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  20. dadouzzu

    dadouzzu Adventurer

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    Wow, a lot of work:-).
    If racetech has done this type of bushing also for this model of fork means that the land is cylindric and is bad..

    Why you didn't buy it instead of using the shim?

    Also in my fork the spring was sitting down around the cartridge but the spring lubricating hole was in the cap and spray the oil on the upper bushing.

    But i found that is noooooooo good.

    The spring was only 0,4mm smaller than the inner tube and when the fork compress it expand and bukle, scraping the inside of inner tube and adding friction.

    All the hard steel shaving coming from the spring and tube fall down and get sucked by the holes on the lower part of cartridge tube during rebound

    Than it goes up ang get sprayed by the hole to the upper bushings and also fall to the lower.

    Than the shavings get embedded in the soft teflon and scratches the ano on outer and eventually the chrome on inner.

    It also goes between the oil seal lips and get enbedded in the piston band and scratch the inside of cartridge.

    Also when the ano wear out it get added to the spring and tube shavings

    I found all this things when i completely dismantled and inspected the first fork at 30kkm

    Now i am using a new cartridge with a small od spring on top supported from the inside, that can't touch the inner tube and no lubricating hole.

    20190615_150844.jpg

    At the last revalve (4kkm) the oil was pretty clean and the outer tube seems well lubricated.
    I will keep the fingers crossed until the next ispection

    P.s. did you measured also the rebound needle and hole?