We have been making performance valves for damper rod forks since 2007. we started with a simple poppet valve design similar to the Race Tech Emulator and YSS PD Valve, we called them the V4S valve. the motorcycle industry is a land of acronyms. These worked as well as any other poppet style valve and we made a few changes to them over the years, cutting the bleed plates down to a 1.0mm bleed hole and making iteasy to drill more if you desired. 

Around 2019 Tom Foster from Adventure rider Magazine and I got together and did a bunch of tetsing on every available DR650 valve I could find. The content of that story is below. What came out of it was an understanding of how the FFRC Plex valve worked and where some other valve designs were good and bad. From this test I set about designing a new valve that incorperated all the positive features i found in the valves I tested. We had a running joke in the design and R&D phase of "whats better then GOLD? PLATINUM". The name stuck, we called our new design a Platinuim valve, for no good reason apart from it sounded better than V4S Mk2.

Whats different about this Platunum valve over everything else?

• We designed the valve to work with a 2.5-3wt fluid. this serves two purposes. The light fluid renders the stock damper rod orifice based damping inneffective, so no requirement to drill the holes out. Second, the light fluid is more suited to a cartrige system with valves (shims) where we want posts to close sooner and reduce fluid mass. 
• The valve controls both compression. This isn't an easy function for a drop in damper rod valve to perform. 
• The valve can have its specification easily changed with 6mm shims. The supplied setting suits a lot of applications. There are bleed shims on both faces of the valve, they can be changed to create more or less bleed. 
• There are 4 outer sealing rings, these allowed us to make significant improvements in low speed sealing
• The valve was initally brass with an electroless nickel coating. We have since changed to 7075 alloy with hard anodising. 

We should get around to doing some marketing on this and our other products. Hopefully this answers a few questions. 

Whilst not absolutely necessary we also reccomened upgrading the springs to suit your rider weight at the same time - have a look at our Teknik Motorsport DIY fork and complete package deals.

Platinum Valve installation instructions are included just in case.

Please note: If you are replacing the fork oil seals and dust wipers the high friction of the OEM seals will affect the performance of the Platinum valves - but will reduce after they are broken in.

Adventure Rider Magazine from 2019

Damper rod forks. (Wassat funny looking pipe with holes in it)

If we had to divide current production front forks into the simplest classes of design it would be

1.Damper rod forks

2. Everything else

Everything else would describe the earliest prototype “cartridge” forks on MX bikes in the 70’s, the take up into production in the 80’s and the pressurisation of the cartridge fork in the mid 90’s. Today, many adventure bikes from WR250R’s to KTM1190’s use cartridge forks of some description. Cartridge design is characterised by a cylinder that has a valve at the bottom, a piston on the end of a shaft and shims on the valve and piston to meter oil flow, creating damping. There are many design offshoots all stemming from the same base design.

So what about the damper rod design? At nearly 50, I’m way too young to remember where and when damper rods came into production. Pre war is a safe estimate. Why do some bikes still use them? Cost. It's such a simple design. A tube in the fork, with holes at the bottom and top. The bottom of the chrome tube forms a rudimentary seal and displaces fluid through the lower holes on the compression stroke, the upper holes on rebound.

What bikes use damper rod forks? Popular adventure bikes are the DR650, KLR650, XT660Z Tenere, BMW F650, CB500, NX650 Dominators. What's wrong with it? Nothing if you chase sheep all day or ride to the cafe. Where the design falls over is damping control. the oil is free to move through the holes at low fork speeds but the holes cause a restriction at high shaft speeds. You wind up with an undamped ride that is both soft and harsh.

Kawasaki addressed this in the mid 80's with a Travel Control Valve on selected models but it soon disappeared. Racetech introduced the "Emulator" in the late 80's  as an upgrade for the lowly damper rod. It was a great success and has been the stalwart of damper rod fork improvement  until YSS introduced their PD about 15 years ago. Since them we have seen a number of damper rod valves emerge all claiming their own features and benefits.

I've been collecting every popular valve with the intention of doing a test on each, under the same controlled conditions to see which valve is potentially the "best". here's the test victims. For the "poppet" type valves I've listed the poppet spring rate and preload as it's one of the main tuning points.

1. Race Tech Emulator with one bleed hole and a 64lb spring, 4 turns preload.

2. Race Tech emulator with 2 bleed holes and 64lb spring, 4 turns preload.

3.Ricor Intimidator, DR650 application. (Reaction valve not locked)

4. Cognet Dynamics DDC for DR650

5.Teknik V4s valve 1.5mm bleed with 11.7N springs, 4 to 10mm preload

6. Teknik V4s valve 2.0mm bleed with 11.7N springs, 4mm preload.

7. FFRC Plex valve, STD, no bleed hole

8. Stock DR650 forks

The test mule forks are a set of late model DR650 forks. We ran the same 7.5wt Silkolene oil at the same height in each set. The springs were 0.42kg/mm and all set at the same preload, 10mm.

Our Roehrig  4K EMA shock dyno ran the same test on all the valves, 40mm stroke, up to 1.5 metres per second. Dampers are velocity sensitive , not displacement, additionally, you need to decide on some testing standards. We test at 40mm to give good resolution at low velocity, while the electromagnetic dyno can run high velocity on low displacement. The software is programmed to remove the coil spring force, air spring force and seal drag so we are only looking at damping. Cool huh?

So, what happened?

Without writing a novel about the results, the "poppet" type units, Race Tech and Teknik had very similar results. From my previous testing I can say the pressure spring preload has more influence than the spring rate. Once we reached 8mm of preload on out 9.5N spring the compression damping failed to increase. This type of valve doesn't develop any additional rebound damping. Interestingly, as the fork velocity rose, the damping remained quite constant, with relatively good response time. this is something that becomes important as the fork moves quickly from compression to rebound cycles.

The Cognet DDC and Plex are similar in design but produce very different results. One area where we don't look in this test is long term durability. I have seen DDC's with bent shims from leisurely adventure riders. Both valves suffered with poor response time but the Plex is a clear winner in building damping force at low velocity in compression and rebound.

Ricors Intimator does well producing compression force (bump force) but the inability for the fork to refill sees quite a poor response as the velocity rises, plus the rebound is unchanges.

The odd one out, the Intiminator, makes good low speed compression force. It has a small refill and suffers in response from this. Testing it's inertia valve on the dyno involves locking the valve in either position or letting the valve float as it would on the bike. I chose to let it float for these tests. While this would change the compression results having it locked, the rebound would not change.

So, what's the result? They are all bad in their own way. It's possible to build a poppet type valve to have the compression force of the Plex, while having the good response time the poppet valves have as velocity rises. Is that worth having in place of the rebound force the Plex makes? I think the rebound force at low velocity counts for a lot.

If you want great forks put RMZ forks on your DR650. All these valves (including mine) don't make a damper rod fork good. If you love your bike but would like a better fork and you have reasonable expectations, most of the valves I tested do an admirable job.

Photos

The whole damn mess is all the Peak Velocity Plots. it's a meaningless bunch of scribble really.

Emulator (Blue) vs Intimator (Grey) this is a continious velocity plot. The closer together the lines are the more responsive the damper is. You can see the "old fashioned" Emulator is more responsive than it's new rival.

Emulators Orange is two bleed holes, purple one. Bit more damping force in compression with one bleed hole.

Plex (red) Vs V4s. (grey) only a little more force at 100mm in compression, then the Plex falls away in a cavitation milkshake. Nice rebound curve though.