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want to revalve my forks

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I have an 02 WR250 and the suspension seems decent but I was thinking of revalving it to see if it can be better. I know I can send it to LTR, and I will if I have to, but I like to be able to do things myself and I don’t mind working on my bike. Saving money is a plus but not that big of a deal.

I think I can handle the mechanical part of the job. I am unsure of the valving to use though. Does anyone have any suggestions for a good place to start with the valving? The base valve looks easy enough to get to but I assume I need to modify the mid valve also. I don’t know if I need to do anything for the rebound. If someone has some information about what shim stacks to use that would be great.

I have also read something about machining some parts to allow more bushing flex. If someone has detains on this I need that also.

I am 190 and ride tight woods. I care most about slow technical stuff. The bike needs to be soft over roots and rocks at low speed, climb hills with lots of loose rocks, and be able to handle slamming into root ledges. It would be nice if the bike is good past third gear but that is not a priority. I like the forks now but sometimes they seem to spike or bind (not sure which) on high speed hits. They also feel a bit disconnected at high speed over loose rocks. I might do the shock also if it isn’t too hard.

I hope someone has some suggestions so I don’t have to go to Gasgas riders for advice.

Thanks

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I have revalved many a suspension, both Husky and Yami. Both are very easy to get the base valve out and make some changes. The thing is Les at LTR have done tones of these, has a mid valve mod that works wonders and understands balance and spring rates as well. I know you can make improvements doing yourself, especially if you just want it a little stiffer or softer and just add or remove some shims but to get the total package your ahead by just sending it to Les.

if you do tackle it yourself a 14mm bolt welded to a 1/2 drive socked and driven by a impact wrench will get the base valves out easy. I'm assuming you know which shims to add an replace to make it stiffer and softer and also which ones are for low/mid/ fast damping?

K

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I'm assuming you know which shims to add an replace to make it stiffer and softer and also which ones are for low/mid/ fast damping?

K

Actually that is the part I do not know. I think the work itself will not be that hard but I have no idea what shim stack to use and what modifications to make to the midvalve. Do you remember what worked well for you? Have you looked to see what LTR did? I don't think I am experienced enough with riding well suspened bikes to really just start making changes and knowing if I have it good or not.

I'm considering LTR but it doesn't seem like it should be that hard. It's kind of like when I rode mountian bikes and people all said that building wheels was and art, blah, blah. Once I finially learned to do it myself I learned it was not hard at all. I would like to now learn some about suspension.

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Well just changing out shims to make it stiffer of softer via and base valve is simple on these forks. BUT, really getting it right and knowing what you are doing is a different thing. Many variables to work with and getting front to rear balance on top of all that is not simple at all. Shims on the base valve can be configured many different ways, oil level, oil height, oil weight, mid valve, rebound stack, base valve mods, damper rod tricks, there really is a lot to it and you can end up with many man hours in it and it is still all messed up. Not trying to discourage you in any way and i have done the same as you are contemplating. You can make it better with messing with the base valve but it will be a far cry from what you get back from LTR. Can't hurt to mess with it and experiment. If you do let me know what the shim stack measures up stock (how many shims and their sizes / relationships, let me know what you don;t like about it stock and I'll try to point you in the right direction.

For off road i revalved a horrible working set of YZ250 forks recently and came up with a 2 stage stack I like. It is a little soft but never deflects which is always my biggest issue in the rock fields I ride in a lot.

K

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Ride, would you be kind enough to explain:

1 What is a mid-valve? The piston pointed out in the attached picture?

2 How can one tell which shims in the base valve are for low or mid or fast damping? Are the biggest (diameter) one’s for low damping?

quiz_midvalve.GIF

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The low speed ones are the large ones usually stacked several deep all the same dia. Depending on how many are stacked this determines the low speed damping. In a single stage the rest of the inverted pyramid of shims is supporting the low speed stack and are thus the high speed shims. The combo of high speed and slow speed shims and how radical the change in dia of the stacked shims determines the progressiveness of the stack. Also the very last few small shims are the support for the whole stack and determine how quick the stack and flex and how far. Total height of the stack and the tapper of the stack also determine the crossover and total flow amount. Then there are two and three stage stacks. Basically what this means is you will have your low speed stack, then a much smaller shim or 2 or 3 or... making a gap in the stack which allows the larger low speed shims to flex further before making contact and being supported by the next stack (stage two) and so on. the combo's are endless.

More low speed means more large same diameter shim that are nearest the base valve.

More high speed means less smaller supporting shims and less height to the smaller shim stack allowing less total oil flow. Also ending with a larger base shim will increase the high speed compression as it has more ability to support the entire shim stack.

I ride in a lot of rocks with a lot of jagged rocky step ups and nasty stuff to deflect off of. I revalved my YZ250 several times and ended up with a two stage stack with medium low speed and soft high speed and a real small base shim. The YZ in full MX setup and about 14 low speed shims and a VERY stiff high speed tapered stack which made it deflect off everything. It was great for big landings but i don't do that in the woods... hell I don;t do that on an MX track :>) So I ended up with about (I need to check my notes) 4 low speed shims, yes, I removed like 10 of them, and then did a two shim crossover (might have been a little to much on the soft side) and then a very tapered high speed stack with the smallest base shim I could get (11mm I think) this resulted in a really smooth light damping setup that was completely different than stock. No deflection, picks up rocks 300% better than stock and really works well. Did the same to the shock.

Hope some of this helps. I'll dig up shim pictures and specs and stuff soon.

About 4 years ago I spent a lot of time in the TT suspension forum, go there as there is good stuff to learn. I built a fork tank once for my YZF250 and it worked great.

Here are some old shots that I found...

fork-stack.jpg

RC-front.jpg

Shock stack...

shock-stack.jpg

shims.jpg

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Thanks.

Messing with the shim stack looks easy enough. I guess I could see what I have any maybe see how different it is then a stock Gasgas stack. The concern I have is that I think the Husky has a weird midvalve. Is it something I can modify myself? I hear talk of people changing it to a checkplate, etc but I have no idea what this means. Does anyone know what good tuners do to the midvalve and how hard it is to do the work?

I guess I need to ride a bike that has better suspension then mine to decide what to do. I like mine better then any I have tried and I have ridden lots of revalved bikes. I don't know if someone has messed with it or if it just came from the factory a little different (maybe they were low on shims one day). It is definitly not harsh though which is the complaint I hear. I think it occasionally spikes on a fast square hit but I don't know if that is valving or binding. I guess it could ride a bit higher in the stroke on steep downhills but not it that comes with a harsh midstroke. The only bikes I have ridden as soft as mine are a 06 250 xc-w (but it felt very disconnected from the trail, no feedback) and a DRZ (disconnected feeling and once pushed would lose traction and knock you on the ground). My bike is soft without any of those bad features so I am reluctant to change anything unless I do it myself so I can always go back. I like it now but hear it can be even better, and since I hurt my knee and can not ride for a while, I just thought I would play with it.

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I can't help you with mid valve tricks, all I know id base valves and sub tanks as well as shocks which are straight forward for the most part.

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OK, thanks. I was not sure what information was out there. When I researched KTM's I was concerned about suspension but saw that there were directions and lots of example shim stacks at ktmtalk. I was kind of wishing that I could find the same for the shiver.

Ride - I'm curious how much sag worked best for you and how far up in the clamps you ran your forks.

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