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I have been riding with KYBs for the last 2 years. The Showas have been sitting. I'm installing the JBI Pro Kit and will give them a try.
Pretty sure I’ve read/seen the same posted somewhere on social media.
I just did a service for my friend on his 23 KX450SR with Showas and he had one side that was super tight on the compression piston in the chamber. To get it apart I pushed the rod all the way in and it let it push out with a little pulling. I got fluid all over the shop when it came up past the bleed holes lol. That side was also a pain to assemble also. The band on the piston must be super tight, but won’t hurt anything after assembling because it doesn’t move. The free piston moves when the rod displaces fluid. The other side was smooth as silk both coming apart and going together. They had 20.2 hours on them and the oil was beginning to get a little used looking.
I’m going to send you a DM about your setup.
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Ah ok, thanks.
Has anyone had a chance to try both the MX-Tech Huck valve (or their Blackjack fork) as well as try the JBI Pro Pech, and can tell us how the two compared with regard to bottoming feel?
What was said by the critic?
I'm curious because, I'm a bit skeptical myself that this new design does much significantly different than a fixed office type. I have a hard time thinking those tapered-thickness petals are going to flex much. And they would have to flex a decent amount to open up the flow area meaningfuly.
Not trying to be negative or anything. If people use it and like it, that's all that matters. Maybe I'll even try a pair in the future...
That was me, yep had the forks locked up in less than two hours. Kawasaki did warranty it though.
I’ve run both styles.
The Huck valve is more consistent because the bottoming control takes place inside the pressurized, closed chamber of the fork. It’s also tunable with shims.
The spring seat damping is a little more variable due to the damping happening in the outer, unpressurized chamber which is prone to aeration. However it is easier to adjust when the damping starts by changing the oil level. Because of this the extra damping can be brought in sooner than the Huck valve if necessary.
Both are good. In my opinion the Huck valve is better for pure bottoming control in the last few inches of stroke. Spring seat damping is better for controlling the lower half of the stroke with some fine tuning needed.
I've got a set Designed for WP Closed Cartridge twin chamber spring forks
WP XACT Pro 7458 / WP Cone Valve Fork
WP XACT Pro 6500 , if anyone is interested. Retail $355 , $200 shipped to US
Email me at racerxx86@kularoo.com![]()
Thanks, that is really helpful!
I've also run both and agree completely with @Broseph
For off road like trail riding/enduro, so far I like the Huck Valve better. It is a lot like the hydraulic bumpstops on my truck in that it only affects the very last bit of travel. So can be plush everywhere right up until it gets ugly.
For moto/GP I like the Pro Perch a little more as the overall feel is a bit stiffer at the not quite deepest portions of travel. It feels as if it effects a greater travel range than the HV if that makes sense.
Desert is still a somewhat unknown. I will be down in AZ next weekend, so will have a true feel of the Pro Perch setup out there after. I have a feeling at race pace the PP will be great, but at sightseeing pace not as good.
I should note I am also using the JBI volume spacers in the set of forks with the Pro Perches. I know that has an effect as well due to limiting the air chamber volume.
Just a other expensive gadget what will do absolutely nothing for average Joe.
If you wouldn't mind sharing, how do you go about tuning the shims for the HV? Are you running custom inputs on restackor?
Has anyone tried running just the volume spacers with noticeable results?
I never did change the Huck Valve shim stack. But it’s there if someone wanted to.
The real world info provided by Broseph and Beta480RX is really helpful. It seems that the JBI Pro Perch starts ramping up sooner before bottoming, while the MXT huck valve is really only the last instance before bottoming. Makes sense.
I ride only MX tracks and like jumping, but I am getting quite old and looking for some extra insurance when I occasionally overjump something.
*** Would you guys say the JBI Pro Pech is more progressive while the MXT Huck valve is more sudden? Which fork mod has a better feel on harsh landings? I am trying to keep my face off the bar mounts on an overjump. If you also have had the MXT National shock, how much do you notice the huck valve in the shock? No OEM shock that I know of has any real bottoming mechanism besides the archaic rubber bumper. ***
Motocross suspension technology has been almost at a standstill for the last few decades except for a slight diversion with air forks which were cheaper for suspension brands to manufacture. In fact, I have read that Showa and Kayaba have been cutting back on internal parts to reduce costs, using simpler parts that are cheaper to make, and even removing some incrementally beneficial parts to again reduce costs. The fact that Showa and Honda didn’t come up with the huck valve themselves is really unfortunate and MXT probably has a patent on it at the moment. Think how many injuries might have been prevented with better bottoming devices. Still it is good to see JBI and MX-Tech still thinking about how to improve on old designs, if the OEMs won't.
Saying the JBI Pro Perch is more progressive is pretty accurate IMO.
I will say from my experience with the Lucky Carbons the Huck Valve was NOT a sudden feeling. At all. Just when you expected metal metal to metal bottoming it never happened. The transition in that last bit of the stroke was still there, just ramped up quick.
Absolutely notice the Huck Valve in the Natty shock. Best way to describe it that i can think of is just the ultimate "dead" feeling in that last bit of travel. Doesn't bottom hard (obviously), doesn't kick back out on you. But is it leaps and bounds better than the Beta Factory set up Sachs shock I have? Not yet. But it also doesn't fade like the Sachs will after the 5 hour mark of a BITD race... Both those shocks are still way better than the stock KYB on my RX.
Now the question is ROi... for me on the moto side, if yiou are in the target range body wise that the stock valving is good, then the Pro Perch is absolutely worth it. If you are outside that stock valving range, the full JBI DIY kit (no matter if you do it yourself or send forks in and have JB do them) is a no brainer.
I will be seeing how the Pro Perch setup works for desert next week when we are prerunning Parker on Thursday morning. Will have the JBI/National setup on the RX and the Beta Factory KYB/Sachs on the RE. Can directly compare and contrast as my co-rider and I swap bikes back and forth.
Pit Row
Yeah Beta480RX is on it.
The Huck Valve isn’t even noticeable until you bottom hard and it somehow doesn’t hurt at all. Same with the National shock; it gives you a little extra factor of safety before you get kicked over the bars on a square edge.
Spring seat damping can be a little intrusive offroad, but it’s probably better for moto than the Huck Valve. It will give you more holdup in the last half of the stroke and you can decide when that extra support begins.
Thanks so much again, Beta480RX and Broseph. The insights and reconfirmation were really helpful. Looking to hear more from Beta480RX as he continues his suspension swapping and testing.
Is this the same suspension guy again or another one dissing the competition?? To make such a comment without any direct experience or rational in the face of those who do, makes you highly uncredible and quite pathetic.
MX tech currently has their own version of the JBI spring perch. It has a linear 3 sided shim. Couple this with the huck valve and it's has amazing bottoming control. BTW the huck valve has been relocated tfor inside the cartridge to the bottom of the fork leg much like a typical bottoming cone. Mind you it still has shims in it.
On a side note it's possible to alter either the jbi perch or the huck perch by changing the oil weight. I've used 2.5, 5 and 7 wt to either speed up or slow down the rate the fork hits the bottoming cone.
Are you talking about MXT's "compound leaf spring mid-valve"?
JBI also sells a titanium sub-valve and leaf spring cup, which may be similar.
I would hesitate to tune my fork using heavier oils as that is going to effect every single aspect of the fork action. Maybe using a very slightly heavier or lighter oil is no big deal, but wouldn't go heavier than 7.5 wt. Better to target the specific action that you want to modify if you can.
If he's just talking about the outer chamber oil then oil weight could be a very good way of fine tuning the pro perch. It will have no effect on anything else.
Yes ,just the outer chamber. We are talking spring perch, Didn't mention mid valves...
I have received most of the new fork parts from JBI, but still waiting for the new batch of titanium Pro Perches to come in. Hope to get the new parts in my Beta RX soon to see how this approach works. What you see in the picture below are the fork oil volume spacers which help provide more progressive bottoming resistance, a pair of titanium sub-valves that also incorporate some technology from the Yamaha SSS fork.. a titanium "leaf spring cup" to provide better hold up during aggressive riding. Additionally is a set of titanium rebound posts and shim stacks for the mid-valve rebound. I will DLC coat my lower tubes and use SKF low friction seals as additional improvements.. modifications I have used in the past and noticed the improvements.
I asked JB Covington how he ended up with this 3rd, very different design of his Pro Perch and if there is enough pressure to get the petals on the perch to flex open. The concept operates very much like a 2 stroke reed valve. JB said he tested different versions with various thicknesses for the titanium reed petals along with different gap sizes for the width of the cut outs over four years. He also used "FEA" to compare the new design with his older design to help ensure he was on the right track to design something better, before the long testing phase started. Then came the years of actual testing to see what actually worked in real life. As to the thickness of the titanium petals, he tried a range of thicknesses, from protypes where the petals would permanently bend and deform to versions where the petals did not move at all, so it would cause a very abrupt and harsh stop. 4 years of testing on the track helped him arrive at the current thickness of the petals, and the petals will flex open if you push hard enough with your fingers. It is like using a supercross perch for the outdoors to prevent bottoming, except the ability of the perch to flex open quickly and reduce pressure prevents it from feeling as hash as a supercross spring seat would. This perch design aims to improve the speed and pressure sensitivity of the fork. This is the concept and it seems to make sense, so I thought definitely worth giving it a try.
I recently did the JBI Spec KYB DYI kit set up for soft MX on my 23 YZ450. The rear is really good now, I used his recommended settings and they are spot on. I just installed the the DYI front kit and tested Saturday I had .51 springs in it and it was too stiff for me even with the comp turned all the way out. I was a bit surprised after the rear going so well. Anyway they were closed Saturday and I couldn't call so I sat around thinking about it a bit, I ran ENZO before with the spring tubes and they only recommended 250cc oil with the tubes. JBI recommended 325cc with his volume spacers which is way more than I was using. Enzo spring tubes take up 70cc volume, OEM spring perches take up 40cc volume, JBI volume spacers take up 40 cc volume (not verified on JBI I read it on the internet.) I did use my TEMU beaker to determine the volume of the other stuff because I wanted to know. I have a race coming up and my only options were keep the .51's and use less oil or keep the same oil level and go with the .48's. I went with the softer .48's and same oil levels, tested this morning and loved it using his recommended clicker settings. Seriously I was so pumped as soon as I got on the track I was like okay this is good. The Titanium Pro Perches were sold out and coming in 2 weeks so I can update when I install those. Anyway as far as JB goes, he is pretty much always available during business hours or gets back to you very soon. Phone is quicker than email which is awesome. I get vibes form this company and I like saying JBI Spec. The KYB Fork DYI install video was awesome, I had a tablet and followed along exactly every step. No DYI KYB shock video available yet but I got it done and it was my first time. So here's my JBI SPEC YZ450F and some titanium valve pics and the track at Barber Motorsport we are racing this weekend.
My JBI Spec Yamaha will be here this weekend: Barber Motosport's SEVMX Vintage race this weekend they have modern classes. Go to Millcreek dot com for details.
What an absolutely beautiful track!!!! I am envious!
My JBI parts are with my suspension guy, awaiting the lower tubes to come back from DLC coating. He has the Ti Pro Perch back in stock and I already received mine. I tried to see if I could move the bendable reeds on the Pro Perch with my fingers and I couldn't at all. Perhaps the internal pressure of a hard landing is enough to bend them. If not, the openings in the perch are so small that I think it would make for a stiff set up. I was also surprised when JB told me to run the same oil level (325cc) with the oil volume spacers that I was using before. I had thought the purpose of the spacer was to be able to run lower oil volumes. I am a little worried it will be too stiff, but will need to actually ride it to see how it works in reality.
Looking forward to hearing how you like the Ti Pro Perch, especially since you already tested with the new valving w/o the Pro perch. You already have the oil volume spacers in there, right?
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