Bladder forks

Questions and comments about converting to beefier forks..
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bradf
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Bladder forks

Post by bradf »

Ever since I got my 01's I have been doing everything I can to edjamacate myself on these rascals. I have discussed this with 6 large suspension shops and have been told basically 3 different approaches to set-up. Two of the shops specialize if off-road, GNCC style set-ups and they both agreed on the same approach. 2 of the MX shops agreed with each other but the MX shops did not agree with the woods shops. There is really no way to make these forks work wonders in the sharp edge world of the west and be acceptable out here where sandy whoops can be large enough to swallow a Californian. That would be rather cool to see though, and they would smooth out the whoops too! Luckily, my type of riding has changed from the left coast (WA) to east coast (north Florida). I am in the process of rebuilding as the fluid was old and I like knowing the seals are new. Beings I am setting mine up for more of an MX world I can get away with less hassle than a major re-valve. 4 of the 6 shops say to disable the bladder no matter what terrain you have which I will do. It is a simple thing to do and it is reversible. If anyone has bladder forks I'll share more detail.
'04 220 w/'01 KX250 USD forks, '02 RM125 Showa shock, Rekluse EXP 3.0, LHRB & all RB'd
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Post by canyncarvr »

No one has asked I'll bet 'cuz they haven't bothered to take their carts apart so see if they have bladders or not.

If you ever take your base valves out with the fork unsprung..and you get sprayed with fluid....you probably have bladders!

...full ones at that! :shock:

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Post by skipro3 »

I've got '02 forks on my KX250. Other than refilling with 5wt oil, they are stock and I LOVE them. I find them just as manageable in the sharp edged rocky stuff as I do in the wide open desert whoops. I do know they have badders, I've had them apart enough to check see. I figured to just leave them in for a base level to compare performance and decided that the forks work so well, I wouldn't bother taking them apart to disable the bladders.

I recommend modifying forks only if you know they are not performing to your expectations.
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Post by canyncarvr »

Sopmetimes I modify/change things due to their failure to conform to my expectations...sometimes I do it because 99% of people that should know say it should be done.

You may HAVE bladders...but that don't mean they are operative units. No, I don't know whether they are or not.

The most common form of defeating the bladder system (not as good as what bradf is offering) leaves the bladders IN the fork.

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Post by Indawoods »

Somehow leaving a condom on doesn't make much sense if it isn't functional! :hmm:
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Post by skipro3 »

The bladders in my forks are functional; i.e. they are installed correctly and all the parts are installed. Someday I might disable them just to see what the difference is, but compared to my Gold Valved, woods shimmed KX forks on my KDX, I like the stock KX ones better.
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Post by bradf »

Ski, do you have stock springs and shim stacks? Until I tore mine apart and measured the spring I assumed they were stock. The shims were in stock config. but the springs were much lighter. It is very common to take shims out of the BV and to replace the springs in these years forks.
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Post by Indawoods »

I HAVE stock 03 KX 125 forks on mine right now. They are still too stiff and I am going to remove a couple of the large washers (springs) on each valve this weekend. This should make them much more plush...which I need. They have .42 springs in them. Granted they are NOT bladder forks, but I think being valved for woods would be better than stock forks.
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Post by bradf »

Inda, a tried and accepted shim/valve adjustment for low speed compression would be to remove all but 4 of your 24's on the BV. You probably have 7 if it's a 125, 250's had 11 of em. Your shims are .15's too, not .10 Try that first as it is the easiest to do. Make sure your cup is NOT like what CC's saw when he pulled his apart. There were some that actually thought they could soften the comp. by flipping the cup and allowing the shims to bend even further. If your high speed comp. is still harsh you might have to get into the MV. Also set the oil level at around 120mm and use 5 wt. There are differences in fork oils, especially when they get hot from use. Not all 5 wt oils are the same. There is a bag-o-worms in this discussion alone to fill a thread 20 times over.

edit added:
***I would never trust e-bay forks to be stock*** bought off someone you know then yes, otherwise pull em apart and check em
Last edited by bradf on 02:50 pm Mar 14 2006, edited 1 time in total.
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Post by skipro3 »

Brad,
I have stock springs and stacks as well. At least I THINK it has the stock springs. I don't have a way to measure for that and nothing else on the bike was modded up in any way, so I believe they are stock. I removed one valve from one leg and is was a stock stack and valve. It was my intention to leave everthing stock as a base point so I could determine what affects changes to bladder, springs, shims would have. What I discovered was that the stock set-up works fine for me. I very lightly bottom on the harshest of hits, I ride about 2 inches, static, into the stroke, the initial fork action is very light after setting the fork triple clamp pinch bolts to about 12lbs torque. They handle wonderfully in whooped out sections of trail as well as stairstep rock single track. I have compared rides when swapping bikes; a 550 Husaberg, a 450 Honda CR, a 510 Husky, a 525 KTM and of course, my modded KDX with RaceTech springs and gold valves. The plushest were the Husaberg but I felt too disconnected from the trail. Kinda hard to judge launches off jumps when you can't even feel the forks compress so what happened was the rear would spank me when I wasn't positioned right on the bike or had accurate throttle control. I found the KX forks to be every bit as ridable as the other forks though. Within 15 minutes of riding, I didn't even think about fork performance on any of the bikes but the Husaberg as I pointed out.
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Post by canyncarvr »

FWIW...I'm running 4-24.s on the top.

120mm, too.

If y'all haven't discovered this...my stack is noted in my bike profile (the 'clicky' part of my sig).

I'm anxious to try out a KX....if I hear an offer this upcoming MDay! Ski's KX-forked KDX is quite a treat!!! He tunes his stuff well.

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Post by bradf »

An easy and pretty darn accurate way to measure fork srpings is: get a piece of PVC that is just large enough to slide the springs in. Make it about 3-6 inches longer than the legnth of the 18.5" springs. I use a 1/2 drive socket that just fits inside the PVC (about a 1 1/4") which will fit right on top of the spring, put a 12" extention on this socket. The extension will stick up out of the PVC by about (aboot in Canada) 6". Mark the extention where it is flush with the top of the PVC. Measure up 1" and mark it. Put the set-up on the scale and zero the scale or note the total static weight. Press down 1" (to the 1" mark) and read the scale. Using the inches to mm and kg to lbs will tell you what your springs are.
1 lb = .4536 kg
1 in = 25.4 mm

If you push down 1 " and the get a 24 lb reading, that would be:
24 x .4536 = 10.8864 kg per inch, convert to mm would be;
10.8864/ 25.4 = .4285 kg/mm

using a digital scale helps.
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Post by Colorado Mike »

that's danged smart there Brad. Thanks.
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Post by canyncarvr »

I'm familiar with that rate check method....

Do I get a kewbie doll? :wink:

Can't say I've tried it...I've never had a digital scale. A one-each analog bathroom scale doesn't work real well. Kind'a sorta...but not 'oh-goody!'

Heck...I can hardly tell the difference between the 22/23# marks on my old analog scale.

Well...actually I'm a liar. I used the inner method vs: the outer. I put a piece of tubing INside the spring, made my inch marks, squeezed, measured. You can use a larger diameter piece of tubing cut an inch longer than the other tube..compress to that 'level'.

It's the same thing...just completely different is all.............

Where's my dollie? :rolleyes:

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Post by skipro3 »

I can't wait for Memorial Day. Then we'll see some high bidding on KX250's I'll tell you what!!!!

You just wait and see.
Jerry

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