Help with a revalve

Berni
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4/27/2022 2:38am Edited Date/Time 5/1/2022 12:30am
Hi, I recently bought a Beta 4t 390 from 2020. I ride mainly enduro, and coming from a 2019 GasGas with Kayaba CC, these bike is quite soft.

The beta has the split OC sachs forks (similar to the Xplor from WP). The forks are fantastic in the slow single trails and rocky sections but they have way too little damping in low speed compression. The clicks do almost nothing.

I want to try with the stock shims before buying an aftermarkit upgrade kit. This is my first time shuffling shims althought I think I have a slight idea from reading in thumpertalk.

My stock settings in the base valve are as follows:


From the piston

2 - 18 × 0,15

1- 22 x 0,10

1 - 25 × 0,10

1 - 18× 0,10

1 - 25 x 0,10

1 - 20 × 0,10

1 - 18 × 0,10

1 - 16 × 0,10

1 - 14 × 0,10

1 - 12 × 0,10

1 - 10 × 0,30


What do you sugest (I have no extra shims) to get more low speed damping (I am happy with high speed impacts).

Thanks
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skyrebel88
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New Fairfield, CT US
4/27/2022 8:50am Edited Date/Time 4/27/2022 8:52am
Add more 18x0,15 shims. Start with one and keep adding from their. You can also increase the size of the 18x0,10 to like a 20.
1
Berni
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4/27/2022 9:27am Edited Date/Time 4/27/2022 9:29am
I have no extra shims so I have to play with what I have....
Those 18x0.15 are bleed shims (don't know if that is the right name), I mean, they do not fully cover the piston ports. I know I should put a wider shim there but don't know which one should I use.
MP818
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Grand Prairie, TX US
4/27/2022 12:29pm Edited Date/Time 4/27/2022 12:35pm
Remove one of the 18mm OD face shims on the piston. Those 2 .15x18 are acting as bleed shims to allow more oil in before affecting the stack. You could also get rid of the .3x10 clamp shim at the bottom which will make the entire stack stiffer since they will bend around the 12mm instead of the 10mm OD. Two options you can try without having enough shims to really dive into it.

*Edit* Using what is there you could valve it to be more progressive without needing any extra shims or getting rid of any.
1
Berni
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4/27/2022 2:47pm
My idea was initially to remove one of the face shims as suggested... Should I move it just before the .1x16?

The Shop

MP818
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Grand Prairie, TX US
4/27/2022 4:57pm Edited Date/Time 4/27/2022 5:02pm
Berni wrote:
My idea was initially to remove one of the face shims as suggested... Should I move it just before the .1x16?
Nope, just start your collection. That area would affect more of your round shaped, rough sections. It sounds like you’re looking for just a little more hold up all together.
1
Berni
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4/27/2022 9:50pm
So if I just remove the shim, wouldn't I get more float and soften the whole stack?

And yes what I want exactly is more hold up. I get excessive diving when braking hard
MP818
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Grand Prairie, TX US
4/28/2022 5:53am
It shouldn’t, but you could always put that 18mm down below the .3x10 to keep the stack height. It would just be a spacing shim which is very common. Float is more so designated for the midvalve compression stack which is below the piston that the rebound stack is on. There are a lot of variables in this base valve you have that I don’t have answers to. Is the shim face of the piston recessed at all? Is there a cup with a spring that the clamping shim rides on like a traditional midvalve typically would?
1
Berni
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ES
4/28/2022 6:04am
Thanks. I have no answer for that as what I posted is the stock valving that I found in a Spanish forum but I have not actually disassembled the base valve yet.
Tomorrow I hopefully have some time and will try what you suggested as it was actually mi idea, I just was not sure what to do with the removed shim... I'll put it at the end as suggested.
Thanks for the help 👍🏼
godog
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CA
4/28/2022 9:33am
Just for a quick and easy experiment instead of changing the base valve shim stack ...throw in some 7wt oil or ATF. If that feels harsh and jarring then look closer at your mid valve float height. Reduce float height by .5 mm will help more with low speed compression and fork diving under braking.
1
Berni
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ES
4/28/2022 11:25am
I already put motorex 7.5w and did not feel much difference. Maybe slightly slower rebound, not able to tell how much affected compression but for sure no harshness at all. The bike floats over rocks.... It is just when braking hard that dives too much and when turning it has like much movement from closed gas to start accelerating making for a loose feeling in the front.
rjg
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CA
4/28/2022 9:08pm
As a suggestion, you check out ktmtalk.com. They have threads about this.
1
Berni
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ES
5/1/2022 12:30am Edited Date/Time 5/1/2022 1:34am
Just to update you all.
I opened my forks and seems like they had already been revalved by the previous owner. The valving I found had nothing to do with the stock one... This I what I found


I changed the crossover shim for the second to last shim next to the clamp. Took 25cl of the 7.5w oil and replaced it with 25cl of 20w oil... Yesterday I went for a ride with a wide range of terrains and speed, and so far happy with the change.... And this allowed to get the clicks to middle of the range (I had them ranging from 3 to 6 from close before the changes).

So all good. Thanks


Flipsid33
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11/24/2011
Location
Canyon Country, CA US
5/20/2022 6:18pm
The sachs forks are similar to the WP Xplor.

Simply put these forks have a hardware problem. The design is cheap and ineffective compared to other systems. No real external compression adjustment. It will blow though and spike. It needs added parts or better yet a complete replacement cartridge.

I have some things we do to the shock to make it much better as well.

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