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Discussion Starter #21
Top row is OEM compression assembly. All are 6mm I.D.
Ill list compressiin as mm 'thickness x OD' From right to left in pic above:

Nut
1.4x10.0 spacer
0.5x9.0
Special shim with main flow holes
Special Main check
PISTON
0.13x17.5 with slits
0.12x17.5
0.12x15.0
0.12x13.0
0.3x9.0
0.3x16.0
0.3x16.0
0.3x16.0
0.3x16.0
0.3x16.0
1.6x16.0 spacer


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Berksglh-

Thanks for the exploded view. Some of those shims are some real funky things, especially the check plate. Seems like that check plate shim would eventually crack and fail. I've never seen anything like this in any dirt bike or snowmobile. The compression face shim especially, but I see/think they are attempting to create several small "reeds" rather than flexing the washer into a potato chip (or are they bleed holes?). Wonder if this unusual arrangement was designed by the boss' summer intern kid with some zany new ideas. Or, maybe these special shims are A-Kit supercross stuff? :)


Thanks!
 

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Discussion Starter #23
Bottom row is rebound. Will list sizes from left to right (I should have laid them both out this way, but oh well...)

1. Threaded shaft is 7.94mm, or 8mm ID shims.

2. Thick flow hole spacer with small step away from piston.
The rest:
0.3x10.5
0.15x22.5 thin flow hole spacer and check
0.12x22.5 slotted check bypass/main flow
PISTON
0.13x18 special shim with outer slits
0.13x18
0.13x16
0.13x14
0.3x10.5
0.3x10.5
Nut


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Discussion Starter #24
Berksglh-

Thanks for the exploded view. Some of those shims are some real funky things, especially the check plate.
I think the odd shims opposite the main stacks just set up a one way check/flow. The shims with slits on the outer diamater seem to set up main stack bypass holes. See picks. In the gold valves, you drill bypass holes in the piston to allow a calibrated flow to bypass. I dont totally understand it, but thats my thoughts. Good luck, and if anyone messes with OEM valving, feel free to post results here.


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Thanks again for the pics and measurements. This is certainly different than a normal MX fork. But,,,, we're working with only 6" of travel and much greater forces, plus likely a tighter budget at the factory.

There are not many changes to be made to the compression stack, but I'm not looking for a major revision either. I just want to lighten up the lower speed sharp bump harshness and get the fork to move a bit more on the street.

I'll be trying some changes within the next month or so, and report back.

Thanks!
 
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I took a first attempt at revalving the compression today. It's definitely an improvement on those expansion seams in the road and/or manhole cover type sharp edge bumps. I left the rebound as stock.

I'll add some ride updates after I get out for some two up rides.

The Vee fork is actually pretty easy to work on, aside from needing a device to compress the main spring and you will need to buy the Race Tech damper rod tool (~$60).

Here's what I have-

185 lb solo rider, 650# Eihbach rear spring on the stock non-modified OEM shock. (shock internal mods coming later)

Springs- Race Tech .95 Kg/mm with standard preload spacer. No additional spring spacers added.

Fork Fluid- Maxima 5wt at 120mm Be sure to push the damper rod all the way down.

(compression stack data)

Nut
1.4x10.0 spacer
0.5x9.0
Special shim with main flow holes
Special Main check
PISTON
0.13x17.5 with slits
0.12x17.5
.10x12 <- new shim
.10x 18 <- new shim
0.12x15.0
0.12x13.0
0.3x9.0
0.3x16.0
0.3x16.0
0.3x16.0
0.3x16.0
0.3x16.0
1.6x16.0 spacer
 

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Suspension tuning update...

Since the last update, I've been riding some solo rides and several two up rides trips with a 160 lb passenger. Most rides have been on paved country roads at 55-70 mph, with a small amount of rough gravel road. With the above calibrations and stock rebound valving, the compression dampening was a little too stiff on some high speed compression hits and the heavier .95 springs overpowered the stock rebound valving. I have needed to make shim changes a couple of times to dial in the compression and rebound dampening.

After all the tuning, I'm pretty happy with the end results. The forks now absorb those low and high speed sharp hits much better that stock, and the stiffer springs hold the front end up much better during hard braking.

I now need to address the dampening control of my rear shock. My stiffer shock spring (650 lb) sometimes overpowers the stock shock's rebound, making the bike wallow a little bit in certain situations, which then can negatively affect the front suspension's action. The shock isn't horrible, but it will need to be done at some time to complete the suspension upgrade.

As a conclusion, I'd recommend this revalve and spring modification to anyone who is a bit dissatisfied with the performance of the stock fork. The improvements are definitely available. The technical challenges of this mod might not be for many folks, and my settings are not likely be correct for people with other requirements, but there are tuners who can perform the work and they can set it up for your specific needs.
 

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Was a week ago while tuning carb on my sherco 300 trials bike. Top end is great, 1/8th throttle is fat and sputtery. Needed a leaner slide or larger strait section on the needle, but was trying different pilot jets.

I tried double blipping over an obstacle and it hesitated then cleared and launched. Dangerous and should have never hit the obstacle like that. Threw my ballance and hit ground leaning left, put leg down and twisted knee.


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Yup, I know exactly what you mean. Before I decided I was too old to continue hitting trees and things and rode single track in the woods a lot I used to know exactly what I'd done wrong almost before the event was concluded. If I didn't I walked back and figured it out. I don't know how that can be, but it's usually almost instantaneous...my mind goes to braking for a tight turn, rear slides out and I was laughing to myself as I slid down the trail.....
 

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Joe i just got new non current 19 dl1000 , i ordered a 700lb spring and 1.0 fork spring , i am curious what your final mods to shim stacks are .Thanks
 

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I went even softer on the fork stacks compression. If I am reading my chicken scratchings correctly, this is what I currently have installed.

The rebound could be a little firmer (maybe add another .15 shim or two). The compression could be a little lighter still if you want a very push ride.

Nut
1.4x10.0 spacer
0.5x9.0
Special shim with main flow holes
Special Main check
PISTON
0.13x17.5 with slits
0.12x17.5
0.10x11
0.10x15
0.11x10
0.3x9.0
0.3x16.0
0.3x16.0
0.3x16.0
0.3x16.0
0.3x16.0
1.6x16.0 spacer

My next step will probably be:

(same stuff as current)
PISTON
0.13x17.5 with slits
0.12x17.5
0.10x10
0.10x14
0.3x9.0
0.3x16.0
(same stuff as current)

Rebound...
0.3x10.5
0.15x22.5 thin flow hole spacer and check
0.12x22.5 slotted check bypass/main flow
PISTON
(Delete the 0.13x18 w/ slits. It causes too much rebound bleed.)
0.13x18
0.15x16
0.15x14
0.15x12
0.11x10
0.3x10.5
0.3x10.5
Nut
 

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For the shock. All shims are the 12mm ID. I might add just a little more rebound maybe, but it's probably as good as this basic shock is going to get. Currently using a 650 lb Eibach spring.

I will caution that this shock's refill and recharge procedure isn't like the common MX or snowmobile shocks.

Also, note that you will need a spring compressor to R&R the spring and you will need custom adapters to mount the Eibach spring. Overall though, the task is not overboard complicated, but just a bit different than the normal.

Stock -->My changes
Nut
washer
20x.0
22x.25
24x.25
26x.20 -> 26x.25
28x.20 ->28x.25
30x.20 ->30x.25
32x.20(4) ->32x.25
->32x.20(3)
Piston
34x.20 (3) Compression stacking is stock.
32x.20(2)
30x.15(2)
28x.2
26x.20
24x.20
22x.20
20x20
18x.20
17x.70
37x.40 washer
15.5x.80
 
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Thanks so much for your time documenting this. I'm going to try your suggested setting on the STK compression and rebound base valves. I was going to go the Race Tech route for valving but it's almost impossible to get anything out of anyone there at the moment and our current distribution in Canada for RT parts is next to useless.
A quick run down on what I've done so far:
Hyperpro rear shock with Motoventures shorter dog Bone for an extra 1 1/2 inch of clearance.

1 1/4" lengthen of damping rods in fork. (I might start making custom built lenghthened damping rods in the future as there are a few other Strom owners that will do this mod)
Race Tech longer fork spring in a .65 kg (36.5x 550 mm. These will be approx 1-1.5 inch too long so will shorten which will increase rate) will also eliminate plastic preload tube so spring rests completely on the preload washer. This will also allow for quicker spring changes as there is no need for spring compressor.
I will be experimenting with the stock pistons until I can get GV for it. I will be 75% dirt focused on this set up and on the stiff side for valving.

Trevor
 

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Here's a pic of the damping rods lenghthened 1 1/4". Roger Goldammer world champion bike builder did the machine work for me. We didn't have 10mm tubing so 7/16" was used and machine down to 10 mm. Oil lock also removed at the same time.
Next up is valving......
 

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Clever Trail Design- Longer damper rods, interesting... Are you sure you want to remove all of the oil lock bottoming feature- maybe reduce the distance by maybe half instead? Without the bottoming cone, you're going to bottom with metal on metal, but you will gain some effective travel.

I think you'll still need a spring compressor of some sort. I needed to compress the spring about three inches to access the jam nut below the fork's OEM spring compression contraption. I calculate it requires about 135 lbs of force to compress the spring by 3" (compression plus approx preload). Or, are you eliminating the spring preload components?

As to the valving & tuning... I'm focused on street tuning with a bit of rough gravel road. The fork stock parts are kind of funky compared to dirt bike stuff, with it's full circle port rather than three or four smaller goofy shaped ports. If you picture the shims deflecting with the OEM piston, it's sort of "all at once" all around the port.. In contrast, the common dirt bike pistons open at the outer edges and progressively allow more orifice perimeter flow as the shims deflect further. Maybe it's just a different method to achieve the same net goal. I'm going for another update today- stay tuned.
 

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Hello Bazooka:
To answer your question yes I've completely eliminated the bottom out cone. You'd have to remachine a groove in the rod to reinstall to accomplish what you want. If you've ever bottomed these forks it feels like metal on metal already.
I'll post some pictures of what I've done for the longer spring. And also have gone a completely different route regards the valving. I am now using a base valve from a WP fork that is machined down to fit into the stock cartridge. there's just no way to get the stock base valve to flow any amount of oil to give you an overall plush ride but also good bottoming resistance.
 

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Here are a couple of pictures of the longer spring mod. 7 coils were cut off giving me an overall spring rate increase of about 1.4 kg per millimetre. Inside of spring was ground out to accept the stock fork tap original preload adjuster stays intact.
 

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Here is a picture of the bass valve that I am using. These came from Riders Edge suspension here in British Columbia. Outer lip was machined off to be able to fit into the stock cartridge. I'm still using the stock rebound bass valve as there are not a lot of options there. Again my valving setup is primarily for off road aggressive gravel riding. I'll also post pictures of my rear suspension setup that will have three different lengths of pull rod.
I have a Kooba Link that is longer than stock to give me a slightly shorter ride-hite then stock. (I will need this when I ride 2 up with my wife) I have the stock linkage and also a Moto Ventures shorter pull-rod for 11/8 extra inch of travel in the back. I'll post pictures of that when I get to that part of the install.
 

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Three different pull rods.
Left- Kouba Link longer than stock giving me a lower rear end for 2 up riding. For touring I will be running a taller seat to open up my foot peg to seat height ratio with the longer link this will allow me to be roughly back to stock seat height to the ground.
Middle- stock length pull-rod
Right- Moto Venture shorter than stock pull-rod this will give a 1 and 1/8 inch rise to the rear end of the motorcycle.
 

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