Convert WP Closed Chamber Bladder Forks to a KYB/Showa style Spring ICS internal cartridge - WP Race Performance Fork Kit (Collective Tuning)

Just an update on the stacks I posted earlier and how the testing is going. So far I've ridden for a few hours with those stacks, now on two different tracks, over the course of three days. I've also had the opportunity to ride my Öhlins bike back to back. I must confess, the WP stuff doesn't feel that bad. We had a lot of breaking bumps and not much to lean against, so traction was a problem all the time. Yet, I was quite impressed with the stacks I made and the grip levels. Initially I thought there wasn't enough damping, but I made some clicker adjustments over the course of the testing and found a happy medium. The forks feel plush at the top of the stroke like my Öhlins do, something I've never been able to achieve before. They have excellent bottoming characteristics with 350cc's and I've kept the bladder pressure around 1.2bar.

The slightly stiffer springs don't seem to be a hinderance what so ever and honestly, riding my Öhlins bike back to back with the modded WP bike (same chassis/engine) I absolutely thought the WP was better in many ways. Sure the Öhlins were more plush at the top of the stroke, but they also went further into the stroke then the WP's, causing a bit of mid stroke harshness that was unexpected. My Öhlins bike felt more twitchy as well, something I've always had a problem with on the Öhlins.

I did some endurance moto's on both bikes yesterday, just going a reasonable pace and was pretty impressed. Even the owner of the WP bike felt very comfortable/confident on the machine, which is really good. I had another rider who wasn't ver familiar with KTM's ride it and he didn't much care for it.

I put those settings into my 2 stroke, will be testing this week! Though in the garage, they don't feel anything like those 14' forks. So maybe my 13' forks on the 2 stroke simply need bushings, they really don't feel good when you push them through the stroke. More on that later…

Made it out today for my first ride with the lower oil height at 345cc's. As you know I was hesitant & skeptical to go with the lower oil height and away from MXA's 370cc recommendation. I must say that the lower volume was quite noticeable with no apparent negative consequences. My forks have never felt so good and the lower oil height absolutely made the front end feel more comfortable than ever, as they handled all chop just really really well. In addition, the forks felt great in the turns as well, though that may be due to the track being a little more tacky than it's been. I am blown away that I no longer experience any deflection or palm slap with the Spring IFP new setup, absolutely none! I can simply feel the fork absorb the energy on every style bump without transferring any uncomfortable energy back into my hands and arms.

 

I think my primary worry with the lower oil height was that I may experience less bottoming control. I did have a few full g-out situations and while the fork did fully bottom, and it was no better or worse than before...I felt the same level of bottoming clank. I did go into two compression clicks to account for the lower oil volume.

 

Overall the front end is performing better than any fork I've previously owned (that only entails two Honda 450's with Showa setups, stock and modified by FC) and most certainly better than any KTM bike I've ridden...and that includes a buddy who had 3k worth of modifications done by Jeremy and MX-Tech. I am so stoked that everything I'm doing continues to improve comfort and performance and I have yet to experience any backward steps (So strange based on my prior attempts). My next step is to install the JBI Perch and go down to 320cc's and see if that provides even more compliance and to see if it'll improve bottoming control. Of all the tuning items on my list, the JBI perch is where I have the highest amount of skepticism. If the JBI perch works, I will be super stoked to move onto modifying my mid-valve stock setup to the same setup my buddy has from PG Suspension. On that note, he is absolutely loving his WP IFP Kit setup as well on his 2014 350sx-f after having 4-5 rides. His previous best bike of all time (2 bikes ago, sold in 2012ish), was a 07 or 08 YZ250F and he has always somewhat regretted selling that bike as he was always frustrated with his RMZ250 and his current 350sx-f in the handling department. Not since his YZ, have I heard him rave so much about a setup until his recent WP Kit IFP setup with re-valve from PG. While it's only feedback from 2 riders, I'm personally certain we have found a cure for the WP CC Fork suspension blues.

 

Shock Adjustment: I also made an adjustment turning in the high-speed compression nut a 1/2 turn in and that may have helped prevent too much travel from being used. I was only able to grab a clip from the chatter whoop section, but I also grabbed some footage from a riding buddy (#8) who is riding a KTM with the 300 kit. From what I can see, my rear shock is more compliant than his...would you concur?

 

With all the improvements on the front end, I'm going to have to explore what direction I can go with my PDS Shock. I never thought that I would make such positive progress on my forks which now is uncovering some shortfalls with my shock.

 

 

Just an update on the stacks I posted earlier and how the testing is going. So far I've ridden for a few hours with those stacks, now on two different tracks, over the course of three days. I've also had the opportunity to ride my Öhlins bike back to back. I must confess, the WP stuff doesn't feel that bad. We had a lot of breaking bumps and not much to lean against, so traction was a problem all the time. Yet, I was quite impressed with the stacks I made and the grip levels. Initially I thought there wasn't enough damping, but I made some clicker adjustments over the course of the testing and found a happy medium. The forks feel plush at the top of the stroke like my Öhlins do, something I've never been able to achieve before. They have excellent bottoming characteristics with 350cc's and I've kept the bladder pressure around 1.2bar.

The slightly stiffer springs don't seem to be a hinderance what so ever and honestly, riding my Öhlins bike back to back with the modded WP bike (same chassis/engine) I absolutely thought the WP was better in many ways. Sure the Öhlins were more plush at the top of the stroke, but they also went further into the stroke then the WP's, causing a bit of mid stroke harshness that was unexpected. My Öhlins bike felt more twitchy as well, something I've always had a problem with on the Öhlins.

I did some endurance moto's on both bikes yesterday, just going a reasonable pace and was pretty impressed. Even the owner of the WP bike felt very comfortable/confident on the machine, which is really good. I had another rider who wasn't ver familiar with KTM's ride it and he didn't much care for it.

I put those settings into my 2 stroke, will be testing this week! Though in the garage, they don't feel anything like those 14' forks. So maybe my 13' forks on the 2 stroke simply need bushings, they really don't feel good when you push them through the stroke. More on that later…

Tye, I suspect they still exhibit the typical mid stroke or palm slap sensation still? In what areas do you feel the most improvement?

Man your bike looks a lot better! Those forks go into the stroke nicely. I also use the compression clicker to help slow them down when the oil level is down.

It's been years since I've run more then 350cc's of oil and have never run more then that in my Öhlins.

Your shock looks MUCH better, very happy with the look of your bike now! :)

No mid stroke harshness with the WP stuff at all. That's because the fork still slows down on high speed hits. It doesn't just blow through the stroke and into the air chamber/bottoming, that's where you get that mid stroke harshness from. The goal is to keep the fork up in the stroke, but have a nice range of easy travel up near the top, to deal with the chop.

To me, the biggest improvement is the top of the travel. When you sit on the bike, the forks actually sag. That's never happened on any WP fork I've ever built. Usually when a rider sits on the bike, the rear goes down and the front choppers out, not moving very much at all. With this new damping setting, there is very little damping at the top of the stroke and ZERO spring preload. So when you sit on the bike, the bloody fork moves into the stroke. After the initial build, I pushed on the forks in the garage off the bike and on the bike, I knew then and there they'd work. They felt just like my Öhlins forks, you can feel the plushness in the damping rod, quite amazing. The forks finally absorb the chop without deflection, without mid stroke harshness and even deliver excellent traction at the same time. I'm honestly jealous because as I said earlier, in some ways they perform better then my Öhlins. Because the Öhlins is a closed circuit TTX system, it behaves funny with fast stuff. It's almost like over slow stuff the fork works fine, but the moment you hit really fast chop, the fork becomes very unstable and under dampened, even though the rebound clicker is almost all the way in and the fork feels great everywhere else. So that's another issue all together.

Anyway, glad you're happy! I like to hear success stories and I think if you take the mid valve apart, you can probably make it even plusher at the top of the stroke. Mid valve is the key to success on these things… but so is that spring IFP and bigger base valve.

Edited by tye1138

Tk2stroke,

The forks look alot better but you kept the front wheel off the ground alot more in this video. It is clear that they are performing better.

The shock still looks like it is getting tossed up into the fender & exhibiting the tendency to buck off the bump stop. (Not enough damping)

Try running the low speed clicker in a bit further. To find a happy spot on the low speed, start with the high speed adjuster turned all the way OUT. Then start turning the low speed clicker in until it gets harsh on the chop. Go back to the stiffest setting that was still relatively compliant. Once you have that setting, start dialing the high speed to a stiffer setting until things start to go south. Go to the best setting before things went bad.

The idea of turning the high speed open & working the low speed is to dial in as much clicker damping as possible. The low speed clicker is a free bleed adjuster (old school orifice damping). By closing it as much as possible, you put more oil flow on the base valve shims. The high speed adjuster is adding stiffness to the shim stack by putting pressure on the shims through a spring. This procedure puts more damping on the base valve shims vs the free bleed hole of the low speed. This is how you dial in the damping for your needs.

So if you start with the high speed adjuster at a stiffer setting & then go to the low speed clicker, you will end up with needing the low speed clicker open more because the high speed is dialing in more damping & the more open setting of the low speed will allow for more free bleed. Too much free bleed will make the bike wallow & use more stroke in bumps & landings.

If the external adjusters don't get you the results you are after, the shock will need to be opened up.

Alot of bikes have a poor shim stack selection for the shocks base valve (compression adjuster). Most of them need work done to the base valve stacks to achieve a truly tunable shock. Surprisingly the ktm is one of the better tuned standard base valve (compression adjuster).

The shim selection is way too thick which won't allow them to flex as they should. This is why running the low speed clicker in too far causes the bike to deflect off square edge bumps even though a square edge hit is a "high speed" hit. With the low speed clicker turned out, a shock can still kick off a square edge bump. There is too much oil flow to quickly pass through the orifice. This is where the base valve (compression clicker) shims SHOULD be opening but the overly thick selection of shims prevents this. The shims are so thick that they won't flex open which means the only passage for the oil is through the low speed hole. In a high speed hit, this is too much oil for the passage to handle, thus the kick. If the shims were more wisely chosen, they would flex open & work as the system was designed. The design is to have the low speed clicker control oil leaving the shock by forcing it through the compression adjuster shims. The high speed adjuster puts pressure on a spring which puts pressure on the shim stack which increases or decreases the resistance of the shim stack.

An overly open clicker setting allows too much oil to pass at low to medium (shock shaft) speeds so the shock can be overly active & wallow through rollers or squat too much off corners or g-outs yet STILL deflect off high (shaft speed) hits.

Without correcting the clicker shims, the shocks midvalve (internal piston) will be damped less than optimal. This makes for a narrow range of tune. If the base valve can be properly sorted, the midvalve damping can be better sorted & the shock will be more externally tunable & have a much broader range of tune.

Again, Ktm's base valve (compression adjuster) is not too bad in comparison to some of the Japanese bikes. Even suspensions that work well can be dramatically improved by sorting this out.

Sorry for the long winded post. I hope I worded it so that everyone can understand what I am trying to explain.

This poor selection of shims turns the shim damped system into an orifice bleed damping system. Orifice bleed systems have a narrow tuning window & are ALWAYS a compromise.

Tk2stroke,

The forks look alot better but you kept the front wheel off the ground alot more in this video. It is clear that they are performing better.

The shock still looks like it is getting tossed up into the fender & exhibiting the tendency to buck off the bump stop. (Not enough damping)

 

Goof Ball Move: After I rode and posted the video I reflected on my ride day when chatting with a buddy. While the shock felt fine in the whoops, I realized that I was having an issue with the shock in a few certain areas of the track. The faces of a couple of jumps and the entrance to the whoops were a "little" cupped out and I was getting enough of a kick to force me to cut-off before hitting those sections. That got me to wondering how such minor terrain issues could have such an effect and I figured something wasn't right. I decided to go check and record my clicker settings and sure enough my low speed compression clickers on my shock was all the way in, not a single click out...DOAH!

 

A few days before riding I reset and recorded all my settings in my notebook and I must have been distracted and never set the shock to my normal setting (all other settings we're at my baseline). It goes to show that it's pretty challenging to determine the performance of a suspension even when trying to be cognizant of it. I'd like to think I would have noticed is more promptly during the ride if the track was more rough. Surprisingly the whoops didn't feel any different than normal and the only clear indicator was upon reflecting on small bumps that had abnormally more impact than they should have.

 

I suppose I'll have to do a redo and see how things feel this weekend with the hi-speed setting turned in a 1/2 turn. Forks still feel fantastic and I most likely going to install the JBI perch after another ride or two.

 

Thanks for the additional guidelines KRP and update Tye. I'll read them more throughly and try some things. I've been a lot distracted with work lately.

Edited by tk2stroke

This is a good thread... Many should read it... 

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