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What have you done to the forks on your 05 250 to make them better!?

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Hey guys Ive had my 05 yz 250 for a year now and these forks are not going to work. Went riding to day and It felt like there were bricks in my forks, everything is extremely harsh and breaking bumps might as well be mountains with these forks. Have any of you had the stock forks reworked to be better, or do most people swap the 06+ sss forks?? I dont want to spend to much but at this point its time to do something about the forks.

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Other than clickers, nothing. I talked to a guy who does suspension and rides 250s and he was convinced the 05 forks were complete junk. Im trying to see if I should revalve or possibly get 250f, 450, or 06+250 forks.

edit: I had an 05 yz 125 too but the forks were reworked by Race Tech, they werent the best but definitely not as bad as the forks right now.

Edited by txmxer

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They can be set up well if the tuner knows how to work with the bottoming system on it. In some cases, it can work better than the '06 stuff. But certainly not in stock form.

Step 1 is get a spring in there that is preloaded correctly.

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Yeah I'll tell ya, even my gopro videos are shaking so bad from the forks, and it seems like they are keen to swap out (this may be a separate issue, maybe I need a steering stabilizer) but I just looked at precision concepts website and they do revalves for $180, if its that cheap I would be willing to try a revalve. I weigh 153 without gear so I think the stock springs arent too bad...

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How heavy are you? What is your riding discipline and how fast are you?

Has the forks ever had a rebuild?

All this, plus:

Is the front axle properly aligned so as to not cause fork binding?

I am happy with my 05 forks. You can definitely make them soft (too soft even). I can post more details of my setup tomorrow when I get on the computer.

Edited by adam728

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How heavy are you? What is your riding discipline and how fast are you?

Has the forks ever had a rebuild?

Last season, fresh oil in inner/outter chambers and seals but not a rebuild per se.

All this, plus:

Is the front axle properly aligned so as to not cause fork binding?

I am happy with my 05 forks. You can definitely make them soft (too soft even). I can post more details of my setup tomorrow when I get on the computer.

I'll double check the axle since I did just remove and put the front wheel back on, but its always been a problem so I dont think its the axle. Details of your setup would be awesome.

I weigh 153 without gear, riding style well im not fast but not slow, recreational rider, havent ridden in a few months so that may be why. Im always improving, feel like in a way these forks are hindering me a bit.

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There are quite a few threads on them. The changes I found help in my 05 250f..

Spacer in the ICS springs 5-8 mm

Spacer in the main spring ~5 mm

Drill the free piston (kind of preventative, search "free piston mod"

2-3 face shims off the rebound - this is probably one of the biggest problems.

I took a few face shims off the base and mv and got rid of the bleed shim.

Go over to suspension and search AOSS, all this stuff will come up.

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I did similar to jlkfg

  • One issue with the 05 fork is that the internal compression spring (ICS) that sits in the free piston above the base (compression) valve is short. At full extension the piston has about 7-9 mm of travel before contacting the spring. Adding a spacer to take up this "slack" helps to make the inner cartrige behave a little more linearly. Think of it as having too high of an oil level, so the air spring rate climbs really high near the end of the stroke. Adding the spacer is like lowering the oil level. On my bike I happened to have a spacer that fit and it 6.25 mm long. Ideally I'd run an 8 mm spacer to take up all the slack.
  • Another issue is the free piston cracking. The "Free Piston Mod" can be found here. http://www.smartperf...YZMODASSEM.htm
  • Your's will look like the set on the right. Basically you are drilling holes to help drain oil buildup that can lead to poor suspension action and even cracked and broken pistons.
  • In my opinion the midvalve is where a lot of the harshness comes from in these forks. Mine were revalved before I got the bike, and it was horrible. A golfball sized rock at 20 mph was painfull with the ubber stiff midvalve setup the bike had. I've been through them a lot of times since to get something that works decent for me. One thing many tuners say is to pitch the first shim, it's a bleed shim. Adding float helps lessen the harshness as well.
  • Basevalve (compression) is something of debate. I've read a few threads of people claiming cavitation is an issue, and one tuner swears going really soft on the basevalve actually stiffens things up once the cavitation is stopped. Not my experience so far, and I need to step mine back up a little stiffer after my last experimentation in there this year. I still haven't gone as soft as one guy recommended though (2 face shims?!)
  • Most guys don't say much about changing rebound. Not sure if the 250 vs 250F has different valving. Spring rate has a big effect on rebound valving as well. I did pull 1 shim on my rebound to quicken it up a little.
  • The fork main springs are short. Typically bikes run ~5mm of preload on the main springs. The 2005 forks have no preload, the spring is loose by about 3 mm at full fork extension. I played around with this for a while and personally could not tell much of a difference between -3 and +5 mm of preload.
  • And finally, the transfer control valve (TCV). This is the bottoming system used in the 2005 forks, only on the 250 and 450, the 125 and 250T were setup differently. It's a very aggressive setup, and effects the last 100mm (~4") of travel. Some guys swear for off road you need to remove this as it's too aggressive and really only allows you to control the first 7.5" of travel. The only way to remove it is to pull the lower lug off the fork leg, which is far from an easy task. I really don't see it as an issue with my bike, I see it as a way to run a little more compliant suspension on the typical 1-4" rocks and roots I encounter, while still keeping bottoming resistance on the occasional ledge, drop, or messup in the whoops.

So of course, first step is to make sure everything is in proper functioning order. No clapped out bushings, broken free piston, galled up inner cartridge stanction etc. Then I'd start with the basic "05 necessary mods", and some simple valving changes, a few less face shims on the compression, and pull 2 shims and increase float on the midvalve. I don't recall what the stock float is, I believe I read 0.30mm before. 0.50-0.60mm is a decent target for trail riding type stuff, rocks, roots, etc. Lower oil level as well. Below is where I'd start.

txmxer.JPG

Edited by adam728
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I played with my 05 forks on my 295 and after multiple valving changes as well as springs and fluid weights I ended up swapping to 06 forks and rear shock. Then valved the 06 forks once and got it right. The 05's can be made right but take time money and the right tuner

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Or - just let ZipTy rework them. They raced the 05's so they know exactly what they need - and their services are relatively inexpensive.

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Or - just let ZipTy rework them. They raced the 05's so they know exactly what they need - and their services are relatively inexpensive.

Just because you've owned a Zip-Ty 05 that I've ridden and had absolutely wonderful suspension, plush, yet firm for big hits...

But yea, if you don't want to go the DIY route, the big name guys can do some great work. The 05 forks are sort of a bastard, 1 year only model. So lots of tuners won't have messed with them, or at least not very much, and may not know the right was to make them work, especially since they are 8+ years old now. Zip-Ty definitely did good on their bikes back then.

Edited by adam728

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