Race Tech GVE & Cogent Dynamics DDC

[norwest]

I have read a few posts on this forum pertaining to the Race Tech GVE and tuning issues or improvements from them. Just a bit of history on them, Paul Thede came up with that idea many years ago and to this day still sell very well. Jamie James won a national championship on them back in the day and Lee Parks had two bikes setup for endurance racing, one with a full cartridge system and one with emulators and they both turned identical lap times. So with that said they can be made to work.
 
The issue with the GVE is they come in the box not setup for any particular bike or rider as it is one of those kits that fit several different weights and style of bike as well as riders. If you decide to get them the first step is go to this link
 
(1) DVS (Digital Valving Settings)
(2) Select Yamaha
(3) Select FZ-07
(4) Select Year
(5) Click (Continue) at bottom
(6) Place an X in each info box until you get to the rider weight and enter your weight without gear
(7) There is no code required for the GVE so you can skip those boxes
( Click Continue
(9) Click Continue again
(10) Enter riding style, skill level, and stiffness desired
(11) Click Continue
 
Now that should give you a screen that looks much like this one.
Couple things to pay close attention to are the following
 
Emulator Valve Spring Rate: Silver 26 lb/in, Blue 40 lb/in, Yellow 64 lb/in, Red 101 lb/in & Emulator Valve Spring Preload:
Most of the time the GVE with part number FEGV S4101 will come with the yellow 64 lb/in spring installed at 2.0 turns preload. So as you can see there is a discrepancy already with what is recommended vs what it actually came with. Easy fix is just swap the springs out as both blue and yellow should be in the kit and set recommended preload.
 
Recommended Fluid:
OSFO 10 is a Spectro 10wt fork fluid, OSFO 15 would of course be a 15wt fluid.
 
Oil Level:
Spring out and fork compressed with emulator installed, (Tip, Fill the forks up to the top of the damper rod and pump the forks to bleed the air out then refill and repeat until fluid stays at the top of the damper rod and no more bubbles coming up when pumping the forks). Compress fork and holding the emulator with mechanical fingers slide the GVE in and make sure it seats correctly on the top of the damper rod. Fill with fluid until you obtain the recommended 130mm fluid level or bring the fluid level up to 120mm and then use one of any tools to suck the excess back out. Install spring so the weight of the spring will hold the emulator on it's seat and pull up fork tube slowly so you don't unseat the emulator. Now measure and adjust spring preload.
 
Of course with the GVE you need to modify the damper rod and and as long as you don't locate any holes down on the damper rod and have them get covered up by the oil lock you should be fine.
 
Now with that all done and the fork back together it should perform pretty good but there are still other things that can be done to tailor the ride to your liking.
 
 
Variable: Valve Spring Preload
Options: 0 - 7 Turns
Primary Effect: Overall firmness, controlling a mushy feel and the speed the front end dives under braking. 2 - 4 Turns initial setting is standard. 1 - 5 turns usable range
 
Variable: Valve Spring Rate
Options: [HASH]26 Silver, [HASH]40 Blue, [HASH]64 Yellow, [HASH]101 Red
Primary Effect: Overall firmness and the ride on square shaped bumps.
 
Variable: Emulator Valve Plate Bleed Holes
Options: 2 – 4 Bleeds
Primary Effect: Initial fork movement low speed damping & plushness before valve plate opens; small bumps, chatter, etc.
 
Variable: Oil Viscosity
Options: 5wt - 30wt
Primary Effect: Use oil viscosity to set rebound, this affects traction and stability. Heavier oil equals slower rebound, lighter oil equals quicker rebound.
 
Variable: Oil Level
Options: 100-180mm
Primary Effect: Sets Final Firmness in the last 1/3 of Fork Travel
 
Variable: Fork Spring Rate
Options: .75 – 1.0kg
Primary Effect: Holds up weight of Bike/Rider, Sets Ride height, Sag, Fork Travel, Overall Front End Firmness
 
Variable: Fork Spring Preload
Options: 5-35mm
Primary Effect: Fine Tunes Ride Height, Sag, Fork Travel, Firmness of Fork
 
So as you can see there are many variables that can be tuned using the GVE. They can be found fairly cheap on the web so they make a decent improvement to damper rod forks.
 
 
 
Ok off to the Cogent Dynamics DDC (Dynamic Drop in Cartridge) System.
 
These are a newer improved version of drop in cartridge for damper rod systems, The nice thing about these is there is no modification of the damper rod required and use a 5wt fluid in the fork. These were developed on a dyno and each application has been tuned on the road for baselines so they can be delivered as a true drop it in and forget it type of thing. They are tunable should the need arise so if you want something just a bit different and they still remain with a price point of under $180.00. These would be an option to the Race Tech GVE and may be a easier install as no mods required, I have used these on a KLR650 and they performed flawless, Yeah i know this is a FZ-07 forum but hey it is what I had.
 
Here is an image of what the Cogent Dynamics DDC look like.
 
 
 
 Anyway that is the end and if you have had either good or bad experience with either please reply as I would be interested in hearing the issues.
 
Terry
 

[pattonme]

Does the DDC have a "penske like" orifice system under the shims? What's the effective diameter of the valve face?
 
Years back when I used to do the GVE thing, one of the major irritants was trying to get it down the tube, sit square and thus seal properly. I resorted to using a long telescoping magnetic pickup, a similar length of 1/2" PVC and once it got mostly positioned, press on the pvc which would seat it. I machined my GVE to take an o-ring so I could feel it 'snick' into place. Still a right messy business if trying to do it on-bike with oil in the forks.
 
Maybe you could share some tips?

[twotone]

"O" ring sounds ideal
Cogents Sell a magnetic tool to make life easy

[Cruizin]

All this talk about fork technology makes the FZ-07 go vroom! Should be everyones winter project this year, start the 2016 riding season off with actual performing forks.

[norwest]

Does the DDC have a "penske like" orifice system under the shims? What's the effective diameter of the valve face? 
Years back when I used to do the GVE thing, one of the major irritants was trying to get it down the tube, sit square and thus seal properly. I resorted to using a long telescoping magnetic pickup, a similar length of 1/2" PVC and once it got mostly positioned, press on the pvc which would seat it. I machined my GVE to take an o-ring so I could feel it 'snick' into place. Still a right messy business if trying to do it on-bike with oil in the forks.
 
Maybe you could share some tips?

The DDC has kidney shaped engineered ports designed just for this application, Had I not been in a hurry to get the DDC's installed I would have taken them apart and got port and shim sizes as well as dimensions. so I don't have the diameter of the valve face. 
The FEGV S4101 has a sizing clip groove in it so you could easily pop a o-ring in that groove to reduce the chance of any fluid bypass as well as locating the emulator. I personally have never seen a need to do that but hey whatever makes the installer happy.
 
When installing Emulators, Intiminators or DDC's I always do a dry run and take a measurement from the top of the fork tube to the top of the spring so I have a reference measurement to know if the Emulator, Intiminator or DDC is properly installed. It also eliminates making any mess with trying to make sure they are seated with fluid in the fork. One method of installing any of the above would be to take a set of mechanical fingers and slide the flexible section through the spring and then grab whichever device you are installing and then slide it down the fork tube and release the fingers and take the reference measurement you came up with from the dry run. If the measurement is the same as the dry run you are seated.
 
As far as removing the device once again have the mechanical fingers handy, Remove the fork cap and washer and spacers and take the mechanical fingers and pull the spring up just barely above the top of the fork tube and grab with your finger and release the mechanical fingers. Now with your finger on the top of one of the coils just rotate the spring so it threads out just like you would a bolt and it will wipe the fluid off and send it back down the inside of the fork. Once you are at the end just pull the spring out and set it on a clean surface. Now grab the mechanical fingers again and grab the device and pull it out slowly and have a rag or towel handy as you will get some fluid from that. Adjust the device and re-install using the install method.
 
Just for kicks and grins on one of my bikes I timed how long it would take to Remove, Adjust, Re-install a set of emulators with unobstructed fork caps. Doing both forks I was just at 20 minutes, Not as quick as turning an external adjuster but not that bad either.
 
Terry
 

[gregjet]

Thanks for the table. Bit late for me as I have Matt's "cartridges" now but it would have been handy and explains a few things about my installation I wasn't happy about. The tables wasn't available when I put my GVE's in but I'll pass it on to whomever I sell the GVE's to. I have alrready swapped the GVE springs to the blue and adjusted to 3 turns for the buyer.
Agree about the O rings for the valve AND for the adapter ( at least my GVE's need a cup adapter). I have to find somewhere to get them from in this tiny town.

[paulibiker]

423LBS dry? How do they come up with that?
 
 

[norwest]

423LBS dry? How do they come up with that? 

Yeah who knows on that one, They just pick a number I guess. I am seeing roughly 397 lbs wet. 
Terry
 

[pattonme]

no, the 423 is 'moist'. actually moderately wet - oil and 1/2 tank of gas I think I remember reading somewhere.
 

[norwest]

Hmmm not according to Yamahas specs,
 
Found a thread on another FZ-07 forum so no link but it is 386lbs on a certified scale with full fuel and all fluids. Not sure how much weight an akrapovic exhaust saves but he had that and changed over to a set of Ohlins forks and a Penske shock.
 
Terry

[avanti]

Yamaha specs and all the magazines say 397[HASH]s ready to ride. I'm assuming with a full tank of gas.

[norcal616]

Mine is 382# wet...

[paulibiker]

Under 400 ready to ride is what I've heard over and over. The Race Tech DVS page pre-loads 423 in the "dry" weight box. Have to think a lot of people are buying the wrong springs and using the wrong settings.

[norwest]

Under 400 ready to ride is what I've heard over and over. The Race Tech DVS page pre-loads 423 in the "dry" weight box. Have to think a lot of people are buying the wrong springs and using the wrong settings.

I sent Paul Thede (Owner Race Tech) an email to have it corrected, Now whether they do or not is on them. But yes buyer beware on spring recommendations from Race Tech and change the weight in the weight box and it will put out the correct rate spring. I just tried a 180 lb rider at 423 lbs and got a .872 rate recommendation and after changing the dry weight to 350 lbs still with 180 lb rider I got a .76 rate recommendation. 
Terry
 

[mike9999]

Thanks for the table. Bit late for me as I have Matt's "cartridges" now but it would have been handy and explains a few things about my installation I wasn't happy about. The tables wasn't available when I put my GVE's in but I'll pass it on to whomever I sell the GVE's to. I have alrready swapped the GVE springs to the blue and adjusted to 3 turns for the buyer. Agree about the O rings for the valve AND for the adapter ( at least my GVE's need a cup adapter). I have to find somewhere to get them from in this tiny town.

gregjet did you drill bigger holes into the damper rod?

[norwest]

Thanks for the table. Agree about the O rings for the valve AND for the adapter ( at least my GVE's need a cup adapter). I have to find somewhere to get them from in this tiny town.

No problem as least you have something to pass along now, Hopefully this can help riders that are going to install the emulators. 
The sealing surface on the emulators is just a metal to metal contact and o-rings are not really necessary as they seal fine as delivered but if one wants to install them then have at it. Race Tech does call out the FPEV AD4103P $19.99 pr adapter for the FZ-07 application.
 
Terry
 

[pattonme]

RT's calculator seems 'off' on some models more than others. I called their tech hotline a few months ago on a bike that was spitting out just silly numbers. Can't remember which model though. Thankfully there's quite a bit of leeway in spring choice vs weight. If you're off by a step it's not a huge deal.

[gregjet]

Yes followed instruction. I calculated the XC area and matched the holes to rod cross-section+10% to help reduce waves. No change to rebound hole as directed. On thing I found just now is the viscosity of the brand of oil I was using was not directly compatible as well. But the table explained most of my problems precisely. I have changed things for whomever purchases them from me and I will advise them on oil wt as well. Made some seals for the Valve/cup/piston joins as well. It can still blow by if it gets a big enough hit but should limit lower speed bleeds and give more control to the proper damping pieces. I turned my own adapters.
 

[norwest]

RT's calculator seems 'off' on some models more than others. I called their tech hotline a few months ago on a bike that was spitting out just silly numbers. Can't remember which model though. Thankfully there's quite a bit of leeway in spring choice vs weight. If you're off by a step it's not a huge deal.

Yes that would be correct as not all tables have the same modifiers to calculate the recommend spring rate. It was a issue I faced quite a bit myself. 
Terry