Help me undrestand this midvalve stack.

[Ed Ventura]

I am into my 2011 45mm zokes, It has been peviouslly vaved by someone else.

I am trying to set it up for the rocks, I have the rebound covered and will expariment with the base valve which is very stiff right now, But the mid valve,

Mid valve looks lke this
18 x1
22 x1
22 x1
20 x1
20 x1
18 x1
16x1

Glenn has posted a midvalve stack working for him in the rocks
21
21
19
12.2
15.2

What is the idea behind the first 18, Is it to to componsate for the Stiff base valve. How does it compare to Glens stack, Mine looks a little stiffer but the 18 has a huge effect I assume.

The base valve
10x 23x1
1x11x1
4x22x1
1x21x1
1x19x1 tappiring down to 1x12x1

Thanks
Ed

 

[Ed Ventura]

Question # 2 about Midvalve vs checkplate in general

My assumptions:

Check plate, Blows open very easy, Just the spring presure with lots of float.

Mid valve with spring and float, The stack takes up some spring presure, you initially get some shim deflection until fluid volume increases or the speed the fluid goes through increases then the hole stack opens.

Mid valve with spacer I.E no float. I saw this in the Pobit thread. Basically just a shim stack that all fluid flows past with shim deflection.

 

[GMP]

Ed,

That 18 is a bleed shim, no one leaves it in. It screws up the rebound as the MV stack can never close the ports.

Checkplate is just a stiff .3mm shim that forms a valve, no flex. Not intended for any dampening control. The MV design uses a flexible shim stack with less float(clearance). The idea is to restrict flow slightly during slow to mid speed fork movement, but flex easy enough to not cause spikes and harshness during high speed movement like on rocks. The MVs with a spacer and no float are usually used for MX and will beat the crap out of you in the woods, plus the shims flex a lot and need constant maintanence.

The stack I posted is very light and helps a little bit keeping the fork up without causing any spikes or deflections. The 15mm shim is the same OD as the tap and just sets up the 1.45mm float. I could go stiffer but just have not had the time to experiment, and this stuff takes a lot of time. I can say its pretty good and doesn't do anything bad. Biggest problem is your rebound, fix that and your 75% there. Go up a spring rate and drop the preload.

Whats with that base valve? Is that ten (10) face shims? Are they 23s, I remember 22s. Anyway, get rid of all but 2 or 3 on the face, leave the 11mm crossover, only one 22 after the crossover, leave the rest and try it for starters.

Also, go up to .44 springs with very little preload.

I'm no suspension expert by any means, but have a good understanding of the engineering and can get something to work decent with a few adjustments. Guys like les can get it right the first time.

 

[Ed Ventura]

Crazy Base valve for sure. I plan on geting rid of most of them. 10 23mm on top.

I plan on removing the 18 and 1 20 from the midvalve to start

I am going to use your (Glenns) latest rebound stack or as close as I can get with the shims I have

I know I could send it off put prefer to do myself. I have had fairlly good luck before, But left my midvalve as a check plate. i would like to see if I can inprove upon what I have done before with a working midvalve.

Ed

 

[BrentMartell]

I will be pulling my zokes apart tonight and will try and remember to post the valving I have as well. Like Glenn the check plate is gone and I went with .3mm float. Base valve and rebound stacks are significantly different. I didn't mess with the mid valve shims too much but did play with oil height and weight. 5wt at 130-135 for gnarly stuff.

BTW- check all your pistons and ensure the holes were properly drilled. Mine were not and caused a lot of issue's.

 

[GMP]

I kept the MV float pretty tame because of the slower speeds and rocks here, but like I said I think I could go more aggressive. Maybe I'll play with it after I get my '12 and get it set up so I don't screw up my only ride. I communicated with pobit a lot when he was on here, he was about my size, probably a bit faster, and rode similar terrain. As I recall, floats under 1mm kept the front up but got harsh in the rocks from his experiments. In order to avoid harshness with smaller floats, you need a soft high deflection stack. This means more maintanence as the MV shims take a beating..

 

[BrentMartell]

OK. I will look at it again to what shims are there. I posted the info on here before but haven't looked for it. Been a little while and memory, like a fart, at this age can not be trusted.

I can tell you the zokes would destroy trail junk, hack, and rocks. Washboarded road transfer sections was riding around on a pavement. So maybe the shims are too light.

Does this theory work on Showa's etc as well. They are stock in the .25mm range. I revalved the honda and went to .35mm while reducing the HS shims as well as mid valve. For example stock was something 10- 16.10's. I took half of those out and then every other from this group 15,14,13,12,11,10,9. Looks like this 14, 12, 10, 9. I know this is off topic but I was curios. The guys who have tested it claim it awesome. I have not ridden it yet.

 

[BrentMartell]

Well, I got delayed on pulling the zokes apart. The oil is drained and then my buddy came over with some 48 WP's that needed service. All sorts of little issue's ensued and time was taken away.

I did have a chance to measure the Showa preload. 6mm. There is a preload spacer inside that is 6mm. Imagine that. I ordered a thinner spacer from FC that is likely half of that. Who know's. When I get it I will know I guess.

Instead of working on the zokes I pulled the Mid valve and measured the float at .4mm. The KTM I did not measure specifically but eyeballing tells me it was 1mm or better. Of course that is open chamber similar to the zokes so who knows. Plus the WP's are gold valved in the bottom. Stock Showa's are are .25mm preload.

I assume the theory of float is similar in all brands? The stock honda has 6 - 20.10 and 4- 17.10 shims with .25mm float. This one is currently running:
20.15
3- 20.10
17.10
15.10
14.10
13.15

So the tuner used a tapered stack with a couple of heavier shims.
Think I will remove the 20.15. That will give me 3-20's and open the float to .55.


BTW- this is a stack from a 45 zoke on a Husky. Mine is not the same but this is what a reputable rider/shop puts out. I have been asked to not give out the name.

23.15
20.1
18.1
16.1
14.1
10.2


22.15
20.1
18.1
16.1
14.1
12.1
10.1
12.1
14.1
16.1
18.25 x3
float .3

oil height 135
stock rebound. On this bike the rebound was good. The gg 45's is not. I added several shims and will get that spec when I can.

 

[GMP]

That looks like a really stiff MV stack, for woods anyway. The face shims are likely .15 for durability at the low float. Rebound pistons on the Husky may not have the bleed hole, and for sure don't use a bleed shim on the stock checkplate, at least my brother's WR250 and TE450 didn't.

 

[BrentMartell]

I will try and get into the zoke tonight and get the shim info. They work very well for woods IMO. I will say my buddy who is heavier than I am and rides the B pace thinks they are bit stiff but he never complains about deflection. I think they are too soft personally but for trail riding the high country they work very well for me.

Glen, what is your thought about the Showa midvalve and float? I am pulling the base and HS compression tonight to see what they did there.

 

[GMP]

My Zokes are firm in the trash but with no bad habits. They could be even stiffer in the faster stuff for me at a 180lb B rider.

Brent, if I said anything about the Showas I'd just be BSing you as I never valved a set. I would think however that the overall MV setup depends on the piston and of course the damper rod/cartridge ratio, which determines the volume of oil per mm travel through the piston.

 

[BrentMartell]

Gotcha. Just wonderin.

I did have a chance to pull the showa's all the way down and have looksy. The tuner did some interesting things and the only thing I did was pull out 1 20.15 shim and opened up the float to .55mm. The HS shim stack on the compression base valve was amazingly different than what I expected. Still pretty shocked. Stock was 10-16.1 then tapered down 15,14,13,12,11,10. The tuner went 1-16.1, 15,13,12,11. Basically he removed 9 of the 16.1's.

I think the open chamber forks are little easier to understand and tune for the average guy. The TC forks are little more complicated to me. Fun project. Glad my suspension guy has forced me to dig in and get my elbows greasy.

 

[GMP]

I know the MX Showas on 4strokes are set up like that, pretty stiff. What you found makes more sense to me. Still a very simple single stage stack, maybe make a dualstage stack?

I usually send my stuff to Les at LTR for the initial go through and revalve. I'll service the forks and tweak things from there but still send my shocks to him for service. Now I suppose I will start doing my shocks too. I hope he recovers ASAP and is able to continue his suspension business.

 

[BrentMartell]

These are have a single stage HS and midvalve. The Base valve is 3 stage with with a race tech piston. Pretty interesting. I left it alone as I am not yet sure what to do with it. I am under the impression the base vavle is going to have less to do with the top portion of the stroke the mid and HS valving.