CRF1000 fork revalve

Discussion in 'Japanese polycylindered adventure bikes' started by Motociclo, Jul 24, 2017.

  1. Motociclo

    Motociclo Long timer Supporter

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    20190409_121625.jpg

    Here's a bit of a guide on revalving Af Twin forks. Most people can get forks apart, so will skip that and show the nuts and bolts. Refer to manual for disassembly.
    I will start with the comp stack.
    Very important. These damper tubes aren't real strong If you squeeze them in the wrong spot. You only want to clamp them in the area circled above. Between the peen mark in tube, and where the other lighter coloured tube attaches. Clamp anywhere else, you a very likely to squeeze and ruin tube.
    This pic is the bottom of cartridge. Need to push comp valve in to expose circlip. May need a little tap to push it in. Not to far though.



    Get the circlip out and pull comp valve out. Will need to screw in the comp clicker bolt to extract. Gently does it. There is a risk the o ring on valve may get damaged on way out. Check it over once extracted. If required, clean up area where circlip sits and the small holes on out side of damper tube.
    It has been noted else where, not by me, that the thicker o ring used on gold valves can be easily damaged in this area of damper tube. Best to ensure sharp edges are gone.

    20190410_135750.jpg
    This is the comp stack. Pretty simple. Remove hex head bolt. Hold valve and shims while you do this.
    Then lay it out and measure up. Take note of how it comes apart. Especially on check plate side. Have look at valve on both sides. They are slightly different. Pic further down page shows both sides of valves. The check plates are common to both valves in assembly.
    The 2 shims at top of played out stack are just spacers. They will go back in place when you re assemble.

    For reference shim ID is 6mm for comp and rebound. The check valve side shim is 8mm.

    The stock comp valving is as follows;
    17*0.10,(5)
    16*0.10,(2)
    15*0.10
    14*0.10
    13*0.10
    12*0.10
    11*0.10
    10*0.10
    9*0.10
    8*0.10

    This revalve is about my third revision, so I will show and list current stack, as follows;
    17*0.10,(9)
    16*0.10
    15*0.10
    14*0.10
    13*0.10
    12*0.10
    11*0.10
    10*0.10

    Previous stack I used had a few more shims and a cross over, felt ok, but wanted to try this stack.
    Race Tech like to use 0.15 shims. On paper they are about 3.5 times stiffer than 0.10, so you use less shims. Thinner shims are more tolerant to bending and feel more compliant.
    Some prep work to the Valve is on order. I use some 800 grit wet and dry sand paper and a piece of plate glass to dress each side of the Valve. Valves aren't dished, won't get into that except to say that dished valves preload shims and create digressive valving.
    Dress valves until the the face is cleaned up. Sealing surfaces where shims sit will be shiny.
    Cleanliness is paramount, so clean all parts before reassembly.
    To reassemble be mindful that valve is different on each side, the check plate side locates on the funny shaped spacer, and has a spring type washer and check plate that need to move freely on check plate side.
    Start you comp shim stack biggest shims first all the way down to the smallest. Is a good idea to measure shims that you plan to use.
    After the last shim in comp stack (in my case, 10*0.10), there is a 0.40mm shim then a larger spacer shim.
    Put a dab of blue loctite and loosely thread completed shim stack on to the base and spray with contact cleaner again, then blow with compressed air. This way shims are still loose and you can blow air between all of them. When done, nip up gently. 6nm gently. Blue loctite is more than adequate. Red is a bit extreme.
    Use a little rubber grease on the o ring before installing the comp assembly into damper tube. At this point if your going to do rebound, then this won't hapoen until you have done it.


    Can't stress enough, take time and inspect each part individually as you disassemble and understand how it comes apart. Keep it all nice and clean and don't over tighten bolt.
    I have been a bit limited on pictures here, (can only get 4 per post), but think I have given enough detail for anyone to understand as they do it. Rebound is very similar in assembly, same rules apply.
    If you go the racetech option, they make it pretty easy with stack selection, but they are rarely bike specific in assembly detail.
    This stack might work for you,may not either. This is more a guide on how to do the job.

    Edit,
    No longer using above comp stack. Have re valved again, gone back to 10wt oil also.
    17*0.15,(4)
    9*0.10
    16*0.10
    14*0.10
    12*0.10
    9*0.10


    Rebound.
    To remove damper rod, you need to knock the oil locks off and remove circlip. Refer to top pic. Can see groove in the rod where circlip lives and locates oil lock.
    Be careful not to damage rod. Clamp it in area above oil lock, as this doesn't slide through any thing,(not under normal operation, only disassembly. Still need to becareful), and hit oil lock down with a punch. A couple of good hits will dislodge them.
    Remove circlip and oil lock and slide out damper rod.
    See pic below.

    Teknik make oil lock replacements if you want to reinstall them.
    Cut only circlip in half that locates oil lock assembly to damper rod, and use rubber grease to locate clips as you assemble oil lock. Makes life easier.
    You will need to disassemble the oem lock to use the actual lock piston on the Teknik mount.
    There is a clip to remove, don't damage and certainly don't cut this one in half.

    https://www.teknikmotorsport.com/af...ttoming-piston-holder-20mm-cartridge-10mm-rod


    If you don't reinstall oil locks, the damper assemblies still won't hit each other. There is about 10mm clearance.
    In fact the oil locks don't bottom out in damper tubes either. They come up 20mm short of bottoming.
    The inner leg hits fork caps on bottoming, oil locks just try to slow it down. It will bottom harder with out oil locks. To be honest i have bottomed forks with and with out oil locks, i struggled to feel any difference.

    Here is a pic of where to hold damper rod to remove oil lock. This is what removed oil lock and circlip look like.
    20191007_201251.jpg


    The pics of the valves,
    Top left, left is rebound, right is comp. This shows the side the working shims sit. Yet to be dressed up.
    Top right, left rebound, right comp. You can see where the valves locate with the recess in the centre of valve.



    Rebound stack disassembled same way as comp. There is some peening on the nut that holds rebound assembly, need to file it flat. Don't just crank the nut off after removing peening, just go back and forth a bit and use a little lube. It isn't tight but just need to be gentle. I suggest clamping the damper rod for this part, right below the rebound assembly. Don't go crazy clamping, just enough to hold.
    See below.

    20191007_200937.jpg

    In pic above, the spacers just do that, take up space from the last working shim to the nut. Typically, the rebound stack,( working shims), gets quite a few more shims, some spacer shims may need to be left out to ensure nut has enough purchase on threads. This has no effect on how rebound works, just something to keep in mind.
    The working shims are the ones that get changed. Note how small the smallest is. Easy to misplace if not careful.
    The shim near the valve, has 8mm ID, it is only a check valve. When disassembling will see how it pieces together.

    Stock rebound,
    17x0.10,(3)
    16x0.10
    15x0.10
    8x0.10

    This is a wimpy stack.
    Use database to select stack if you like.
    Or if using Gold Valve setup, disassembled per these instructions and build stacks to there specs.
    There isn't much difference between gold valves and stock valve. You could use RT specs on stock valve.
    I use 10wt oil, so refer to appropriate stack if using RT data. They usually go down 2 stacks to accommodate oil viscosity.

    This is my current rebound stack.
    17*0.15,(3)
    17*0.10,(2)
    10*0.10
    16*0.10
    12*0.10
    9*0.10

    This stack could be used for springs from 0.70 to 0.80. Would just need to adjust rebound adjuster. It works very well. I use 0.78 fork springs.


    Re assembly, same precautions as comp, take time, understand how it comes apart, keep it clean. Only just nip up nut, 6nm, with some blue loctite.

    Remember, cleanup the rough edges on the damper tube where comp valve lives. Both the holes and where the circlip lives. A bit of sand paper or a dremel will sort it. Just enough to smooth out. Then thoroughly clean the tube. Clean, clean, clean.
    Lube up damper rod and rebound valve and reinstall rod to tube.
    Comp valve can then be installed. A bit of rubber grease on o ring and push it in.
    Re install circlip, then use the damp rod to gently seat the comp assembly to circlip.



    Refer to data base for oil heights etc. There is a section in there for oil height setting for aftermarket springs. This is important to understand or you risk raising oil height to high and causing seals to leak.
    There are valving options to choose from, could pick a valving setup to suit springs and weight. They are all based on 10wt oil.


    https://advrider.com/f/threads/crf1000l-spring-and-valving-data-base.1363798/


    On re assembly, if you follow manual to screw on fork cap to damper rod, you will end up with only 1.5 turns of rebound adjustment.

    To set rebound needle, screw all the way out, then screw in about 3.5 turns.
    Screw fork cap on gently until you feel needle just seat.
    Hold fork cap and nip up the lock nut. Recheck to see if you have the approx 3.5 turns in the rebound adjuster.

    Be careful tightening lock nut. Nip up firm only. A little blue loctite doesn't hurt either. Use sparingly.
    I have read of a guy that snapped threaded end off damper rod from overtightening.
    Be careful. Damper rod can't be purchased seperatly, only complete cartridge, $500aud. Nasty.


    I know i have repeated a few things, but can't stress enough, take time, double check every step, understand how it goes together and keep it clean.
    It isn't a hard task, but does require a bit of patience.
    #1
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  2. CrStep

    CrStep Been here awhile

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    Thank you for taking the time to do this tutorial.
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  3. Motociclo

    Motociclo Long timer Supporter

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    No worries. If it helps anyone, then that is good.
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  4. Motociclo

    Motociclo Long timer Supporter

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    There maybe a way to extract damper rod with out removal of oil locks.
    damperrodoillocks.jpg
    In above pic, on the cartridge you will notice that it has 2 parts.
    The smaller lighter coloured piece may be able to be unscrewed. There are stake marks that need to be drilled out, very gently and not to deep.
    From here, would clamp the lower portion and apply a bit of heat and tension to undo the top piece. It will be tight due to locking agent used.
    I haven't tried this, but is done on other forks. KYB in particular.
    There is a peen mark that goes full circumfrence of cartridge. This holds the bush in and i feel will make impossible to try what i have just mentioned.
    Older KYB forks have a oil lock that unscrews, great idea. I am looking into modifying the oil lock to do the same.

    Edit, had a spare damper cartridge, so decided to try and unscrew.
    Drilled out 4 peen marks, heated to nuclear level, and started the turning.
    Got oil lock end to start turning. It isn't screwed in though. They appear to be pressed together. That scraps that idea of separating them.
    Oil lock on damper rod needs to be removed to release damper rod from tube.
    #4
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  5. Junglejeff1

    Junglejeff1 Long timer

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    Very nice write up.
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  6. Junglejeff1

    Junglejeff1 Long timer

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    I have to ask.why are you running such a heavy fork spring.
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  7. Motociclo

    Motociclo Long timer Supporter

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    Just couldn't get an acceptable sag level. On Af Twin I wanted around 65 to 70mm.
    I tried a spring combo of 0.85/0.60 to give a 0.725 rate and still had a lot of preload screwed in.
    I have always run biggest spring possible that let's me still get rider sag.
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  8. Junglejeff1

    Junglejeff1 Long timer

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    I just was thinking that's a lot of spring.
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  9. Motociclo

    Motociclo Long timer Supporter

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    So did I at first. Crunched plenty of numbers. That's what I came up with, it seems to work ok.
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  10. Junglejeff1

    Junglejeff1 Long timer

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    Is your steering still pretty good and what shock spring kg are you useing?
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  11. Junglejeff1

    Junglejeff1 Long timer

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    Is shim restacker worth getting?been thinking about purchasing the program.Have you had decent luck with it?I would like to learn more.
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  12. Motociclo

    Motociclo Long timer Supporter

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    I think it is. Like any program it takes a bit of time to learn and understand things. On the most part it is very intuitive.
    The website for it has a lot of helpful info.
    I spent a lot of time comparing valving setups from many bikes to get an idea what " a good setup" is like. It makes it very good for that.
    I say do it, will only expand your knowledge.
    Forks on Af Twin are pretty basic compared to Twin chamber forks, I found it agood place to start.
    I have been doing suspension stuff on and off for years, but only really race Tech install, this takes a lot less thought.
    Only been recent times I have gone "free style" so to speak.
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  13. Junglejeff1

    Junglejeff1 Long timer

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    Same here.want to free style more and save money.Shims and 600 grit wet paper are way cheaper.Played around with light changes on mx bikes with some success but just for locals.Kind of a wierd hobby I guess.I walk in house and wify knows I'm playing with shocks from the stink lol.
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  14. Motociclo

    Motociclo Long timer Supporter

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    Addictive hobby. I think I need rehab at present!!!!
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  15. Junglejeff1

    Junglejeff1 Long timer

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    For the hell of it check that 8mm x.10mm clamping shim.I was shim hunting today and went thrue my bag of AT shims and it is .20 thick.
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  16. Junglejeff1

    Junglejeff1 Long timer

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    Oh ya.I tried drilling the peening and unscrewing the upper part.Screw that i'll deal with making new oil locks.I hit it with heat and even and them bitch's be tite.The bigger dampers on more modern forks are way easier to do with out damage.
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  17. Motociclo

    Motociclo Long timer Supporter

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    I never tried myself to undo, thought it may have been an option.
    Oil lock removal was easier I thought also.
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  18. xaviKR

    xaviKR Adventurer

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  19. Motociclo

    Motociclo Long timer Supporter

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    Shims are 6mm ID for forks. Interchangeable between comp and rebound.
    Shims for shock are 12mm ID, also interchangeable between comp and rebound.
    #19
  20. Junglejeff1

    Junglejeff1 Long timer

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    Now I want to bang my head against wall.The springs I put in are too soft.RT is recommending there stiffest spring they have for these forks.A 1.1 I believe.According to them your calulations are damn good.The valving I am using now on compression is way different than what you have.Going to order proper spring tomorrow and have RT analyze your stack for my use.Going to set bike up better for the sand.Soft forks suck in sand.Will keep you posted on what I end up with.They told me I should be running 10 wt to slow rebound down until I told them the rebound stack I am running.5wt it is.
    #20
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