Fork revalve - Kawasaki Versys Forum
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post #1 of 84 (permalink) Old 04-04-2010, 11:19 PM Thread Starter
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Fork revalve

Pulled the forks apart today. 1st oil chg at 1k, oil was dirty, now at 4k, oil was really dirty. If you haven't changed your fork oil yet, your fork bushings ain't happy. It was so dirty I broke down and did a spring polish. That should help.
I don't really have a problem with the spring rate, so I'm leaving that be. Oil weight is ok with 6w BelRay (a mixture of 5 and 7) and the oil height was only 20mm lower than stock, which may explain why I never bottomed. I don't care that much about the rebound stack as the rebound is workable, but did polish the needle end of the rebound rod and took off the sharp edges. I'll polish the cartridge rod in the critical section as well.

Took out the compression stack and here's what's there-
3 ea. .4mm x 11mm -probably spacing washers
.2 x 10mm -probably a clamping shim
4ea. .15 x 17 shim stack
valve body/piston
.41 x 17 check valve
spring/hat
allen bolt (glad it's a showa)

Wasn't there a recent article where Jim Lindemann said the forks were pretty good with just some adjustments, at least for his magazine test ride? This shim stack made me think of that. LE forks have good feel but are on the firm side, if I recall, great for the track.
Haven't yet decided what the new stack will be, but I will probably replace one of the .15 x 17 with a slightly smaller shim farthest away from the piston.
It's different thinking about shim stacks when there is only one damped leg, a small adjustment should go a long way. I'm in personally uncharted territory here.
If anyone has a good stack to post, please do.
The piston looks like it flows pretty well. I don't think there's a need for a gold valve..I'll just chamfer the ports and lap the sealing faces and call it good.
I was tempted to remove the bottom out cone for more travel, but you never know what you're going to hit on the street these days, so I just modified the shape slightly for a softer landing.

Last edited by tomla; 04-05-2010 at 12:30 AM.
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post #2 of 84 (permalink) Old 04-05-2010, 08:52 AM
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Hi Tomla,

If you still have them apart can you measure the shim ID? Probably 6 or 8mm.

Most off road fork valve stacks use .1mm thick shims. So if you've ever looked at a dirt bike stack you would see a nicely shaped upside down christmas tree. The shims above the 15mm are lowspeed. Below it are high speed.

Valve Body (imaginary offroad stack)
25 x .1 (6)
15 x .1
22 x .1
20 x .1
18 x .1
16 x .1
14 x .1
11 x .1

Notice in the versys stack is all low speed shims pivoting on a 10 x .2 shim. This poorly shaped stack and the fact that the oil must flow through a 17mm valve means that the jolt you feel in the handlebars when you hit a pavement crack or freeze joint at speed is due to the fork hydraulically locking.

Valve Body (Tomla's Versys)
17 x .15 (4)
10 x .2
11 x .4

This is why when you reduce the oil viscosity the fork operates more smoothly due to the fact that more oil can flow when you hit something that makes the fork move very fast.

Improving the fork performance will certainly take a few attempts. Maybe we could tag team it. Some pictures would be awesome. (Comp Valve body close up, both legs.) Dimensions of the damper rod, rebound shims, cartridge ID.

If I were to revalve the stack Tomla posted I would start with something like this. 7.5wt Motorex Fork Oil stock height. This stack would reduce the lowspeed damping slightly on initial fork movement, then allow the shims to flex farther off the valve body during a higher speed obstacle. Stack would be more progressive.

Valve Body
17 x .15 (2)
14 x .15
16 x .15
12 x .15
10 x .2
11 x .4

I've been waiting to take mine apart until after a track day but I may have to do it sooner. I actually like the way the forks perform on smooth road. Its just when I hit the wash-boards on the gravel that I worry

Something from the Racetech school. Useful for substituting one thickness shim for another. So an example use of the table is that if you had a stack with a 17mm x .15mm shim that needed replacing (bent) you could replace it with 3 .1mm thick shims of the same diameter.
Shim Thickness coefficient
0.1 - 1
0.15 - 3.4
0.2 - 8
0.25 - 15.6
0.3 - 27

Last edited by Phoneman064; 04-05-2010 at 08:54 AM.
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post #3 of 84 (permalink) Old 04-05-2010, 11:35 AM Thread Starter
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Good feedback, phoneman..many heads are better than one.
The shim i.d. is 6mm, the damper rod is 10mm, 20mm cartridge.
Your imaginary off-road stack uses a crossover shim in position 2. I'm thinking about that, but with only one side doing all the damping, that's going to be amplified. It would soften the initial hit but you'd get hit harder after the delay. May be a moot point.
Yea, I'm not too impressed with the stock stack either, but I can see how it would work...it's caveman as hell, and with the oil height so high, it just keeps you from trashing your forks but ain't exactly plush unless you're a clydesdale. Good trackday setup!
"a 17mm x .15mm shim that needed replacing (bent) you could replace it with 3 .1mm thick shims of the same diameter." I think you meant 2 17 x 15's, but yea, that's a good trick.
I'm used to thinking about 2-legged damping, and find it hard to look at the stack as doing twice-ish the work...I would think converting both sides to be a good (and relatively easy) thing to do, if only for valving flexibility.
new stacks I might go with, heavily influenced by what shims I have laying about.
.15x17
.11x16
.17x15
.15x14
or
.15x17
.15x17
.11x16
.15x15
or
.15x17
.11x16
.15x15
.15x14 this is the one I'm going with today.

Last edited by tomla; 04-05-2010 at 12:16 PM.
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post #4 of 84 (permalink) Old 04-05-2010, 03:47 PM
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Quote:
Something from the Racetech school. Useful for substituting one thickness shim for another. So an example use of the table is that if you had a stack with a 17mm x .15mm shim that needed replacing (bent) you could replace it with (3) .1mm thick shims of the same diameter.
Shim Thickness coefficient
0.1 - 1
0.15 - 3.4
0.2 - 8
0.25 - 15.6
0.3 - 27
Hi Tomla,

I provided the above table for reference. A .15mm thick shim is equal to quantity (3) .1mm shims. It is not linear. A .25mm thick shim is equal to (15.6) .1mm shims. That is all I was pointing out.

Thanks for the ID and rod cartridge dimensions. Its nice to be able to have some parts on hand before one tears something apart

One other thought is that you might want to standardize on a given off the shelve oil viscosity since you are changing the stack. Also it will be very important to keep track of oil height. The air column can make as much a difference in performance as any valving changes.

-Dave
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post #5 of 84 (permalink) Old 04-05-2010, 05:37 PM
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Quote:
Originally Posted by tomla View Post
I'm used to thinking about 2-legged damping, and find it hard to look at the stack as doing twice-ish the work...I would think converting both sides to be a good (and relatively easy) thing to do, if only for valving flexibility.
Did you take the left fork apart and verified there is a different setup (or nothing but the rod) in there?

The advantage I see to a left fork conversion to adjustable rebound is that you could go with an even lighter oil (say 2.5w) to reduce the compression harshness and adjust the rebound to suit your needs better.


Gustavo


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post #6 of 84 (permalink) Old 04-05-2010, 06:02 PM Thread Starter
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Thanks for the clarification, phoneman. I didn't realize 3 together of the total thickness wouldn't behave as one until you pointed it out. It's so obvious now!

setup-
192# naked
62f ambient
tubes 11mm above triples
stock fork springs
40mm rider sag
rebound 1 turn out from full hard
oil height 125mm L, 135mm R
oil 25% bel ray 7w, 75% bel ray 5w (see what happens when you shop on Sunday?)
base valve stack-
.15x17
.11x16
.15x15
.15x14
damper rod polished with 800 grit, piston faces lapped with 400, then 800 grit, back of piston radiused, front lightly chamfered, light spring polish, all sharp edges taken off springs.

It's nice. Plush w/o being soft. Soaks up the hi velocity bumps that used to hit the handlebars with a little sting. Not the best I've ridden, but I'm pretty chuffed. Very good sport-touring setup for me. Might be a good track day setup for a bumpy track with a lighter rider, too.

As far as what's in the L leg, there's nothing in there but a dummy cartridge.

Last edited by tomla; 04-05-2010 at 06:07 PM.
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post #7 of 84 (permalink) Old 04-05-2010, 08:10 PM
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Quote:
setup-
192# naked
I'm also 192# and I also ride naked.
If the setup works for you I may need to try it as well.

Am I reading this right, is the stock setup just 4x .15x17 shims?

I spent today changing out my generator cover with one from a 650r to get rid of the last of my road rash from last season.
I'm running out of stuff to do. If I don't line out a new project I'll end up bolting on random crap like a KLR owner.
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post #8 of 84 (permalink) Old 04-05-2010, 09:17 PM Thread Starter
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I'm running out of stuff to do. If I don't line out a new project I'll end up bolting on random crap like a KLR owner.
first one to bolt on a milk crate for a top box gets banished from the forum...
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post #9 of 84 (permalink) Old 04-25-2010, 02:09 PM
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Observations about this fork 2008 Versys.
- In stock form fork is harsh over square edge obstacles (dis-assembly, re-valve, and subsequent ride confirm that valving was hydraulically locking). Shims could not flex enough to allow sufficient oil flow on HS obstacle.
- Springs are slightly progressive. .8kg/mm to .9kg/mm (note that with sag taken into account you are operating in the .9kg/mm range. Measured with Intercomp Fork spring tester.
- I liked the stock bottoming resistance and find that the stock oil heights are suitable for re-valve as well.
- Base valve is of good quality and is not a factor in the hydraulic locking issue. Won't be as tunable as a two leg setup but after riding the revalve am very happy with performance. Notice the large ports in the attached picture. This is very similar to Showa units that I have serviced in the past. Nothing like the restrictive valves from kayaba on past Kawasaki's.

Without a doubt if you have a qualified suspension tuner service the right fork leg and apply the following valving you will be very happy. Harsh hits from fork are completely gone. I wouldn't even take the left leg off, unless you wanted to change the oil.

My settings
Rebound 1.5 turns out
Fork Oil Right Motorex 10wt / 90mm (stock height)
Fork Oil Left Motorex 10wt / 75mm (stock height)
Fork Right Base Valve 20mm Showa Style Modern
17 x .15 (3) ----------- removed (1) 17mm LS
14 x .1 --- HS
12 x .1 --- HS
9.5 X .2
10 x .1 (2) ------------ added to allow low speed shims further deflection
11.4 X .4 (3)
Fork Left (no valving)

Cartridge OD 22.7mm
Damper Rod 10mm
Springs are slightly progressive .80kg/mm for first 50mm
then increase to .90kg/mm
Notice that springs are turned down on top side to seat properly in spacer.
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post #10 of 84 (permalink) Old 04-25-2010, 02:14 PM
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post #11 of 84 (permalink) Old 04-26-2010, 07:40 PM Thread Starter
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It's interesting to see how different our stacks are, and we're both happy. I'll bet yours has a bit more feel to it. I also agree there's no rush to get damping in both legs once you get a decent setup. I'm getting a lot of feedback from the stock shock after the front just soaks up whatever, so that is a good validation tool for the front. It'll be nice to get the Elka on the rear at some point as it's really a sore spot, no pun intended. It's good to have that spring rate info, too.
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post #12 of 84 (permalink) Old 04-26-2010, 07:45 PM
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Any special tools needed in order to take the cartridge apart?
Or for the whole job in general, for that matter.
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post #13 of 84 (permalink) Old 04-26-2010, 09:19 PM
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Any special tools needed in order to take the cartridge apart?
Or for the whole job in general, for that matter.
I use the Racetech Spring Compressor TFSC 01

You should also have an impact to remove the cartridge bolt from the bottom of the fork leg. I saw some loctite on the threads so it probably won't come out without the impact. You'll need a long hex key socket.

Other than that you just need a way to lift the front end. The KwikLift stand I had wouldn't work (arm wouldn't reach the hole in the bottom triple clamp). Other stands probably work ok, just can't use the ones the lift on the fork leg bottoms.

A propane torch is handy to heat the base bolt to break the loctite on that once you take it out of the cartridge.

A 14mm and 17mm spanner for the damper rod. A 24mm spanner for the fork cap.

The shims are important as well as the brand / viscosity of oil. I tried 5wt Motorex but that was too light for the rebound circuit. 10wt gives me 1.5 turns out. I think 10wt is the best for the most rebound adjust-ability. Didn't try to remove the rebound valve looked like the bottoming cone was pinned to the rod and that cartridge was pretty low tech stamped steel. I thought it best this go around just to stay with the compression valving for now. Any parts unlimited dealer can get motorex so i would recommend that. Not all oils are the same viscosity for the same published weight.
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post #14 of 84 (permalink) Old 04-26-2010, 09:25 PM
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I'm getting a lot of feedback from the stock shock after the front just soaks up whatever, so that is a good validation tool for the front. It'll be nice to get the Elka on the rear at some point as it's really a sore spot, no pun intended. It's good to have that spring rate info, too.
I know, its so interesting to see how much of the jolt from the square edge bumps in the road was due to the shock. Now that he bars are so supple , the sore spot is definitely further back. The spring tester I have will do both fork and shock springs, so as soon as I get a chance, I'll measure the shock as well. Its just too bad they couldn't have made that thing re-buildable.
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post #15 of 84 (permalink) Old 04-27-2010, 07:55 AM
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first one to bolt on a milk crate for a top box gets banished from the forum...
Even if it's a red Sealtest milkcrate? I only use it for beer runs.
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post #16 of 84 (permalink) Old 04-27-2010, 07:08 PM
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Damnit.
I bought a Versys thinking that its main advantage was that it could be anything you want it to be.
Now I'm beginning to see that what other people want it to be is often quite lame and uncool.
You're really cramping our style with your ghetto milk crate nestled between italian panniers.
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post #17 of 84 (permalink) Old 04-30-2010, 10:42 PM
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Who makes the replacement shims, and where can you get them from?
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post #18 of 84 (permalink) Old 04-30-2010, 11:50 PM
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I got a huge improvement in my Kawasaki 500 by putting racetech cartridge emulators in the forks. Is this something that would work in the versys?
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post #19 of 84 (permalink) Old 05-01-2010, 10:34 AM
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Invader, You can buy shims in qty (1) from www.racingsuspensionproducts.com.
Racetech also sells bags of 10. I haven't bought any for a couple of years so I'm not sure what the prices are.

Twowheels, the Versys already has cartridge forks. The cartridge emulators would not work.
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post #20 of 84 (permalink) Old 05-02-2010, 09:46 PM Thread Starter
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tools

for a spring compressor, all you need is the low-tech 2" plastic pipe coupler with a couple of bolts in each side. you don't need to cinch the bolts down on the rod, only compress the spring far enough so the stock spacer will catch under the nut and give you access to the nuts. sure, you have to be a little careful, but it works great, even when putting the rebound side back on, in which you screw down the rebound screw on the cap to O turns out, then screw it down till you feel the needle seat, then screw the bottom nut UP to the cap. as long as you have 2 wrenches on it, the spring will stay captive.
for getting the bottom bolt out, I was able to use a long hex wrench, but a 4" long 3/8" drive hex socket would have been sweet.
to hold the cartridge, get a piece of 2x4, then drill a 3/4" hole in the middle and saw cut the wood down the middle. you can then use the split 2x4 as a cartridge holder in a vise to get the bolt loose holding the shim pack.
for oil height, you can get 60ml syringes (a 10ml would work ok, too, just take longer) at irrigation or farm supply or medical supply stores, then attach some clear tubing ending in a piece of rigid tubing of your liking- i used copper tubing I had laying around. then mark your oil heights on the rigid tubing w/tape and you're good to go.

Last edited by tomla; 05-02-2010 at 09:50 PM.
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