dwb79

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About dwb79

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  1. There are a few manufacturers making drop in valves with shim stacks for damper rod forks, but they present two problems. 1. The large volume of oil flowing through a damper rod requires very light shim stacks as not to produce too much damping. A cartridge in a normal fork has +20 shims, whereas a Cogent DCC (for example) only has about 3 shims. Having a high oil flow with a light shim stack causes the shims to flex a long way and they often develop permanent distortion. This then prevents the shims from sealing on the piston face and you will loose damping. 2. The damper rod will struggle to refill with oil on the rebound stroke when any form of restriction is added to that circuit. Once these drop in valves with shim stacks are fitted, you can feel the cavitation within the fork even just pushing up and down on the fork by hand. If its happening at these low velocities, imagine what is happening at higher velocities. I guess this is why most manufatures stick with the tried and proven method of a valving plate controlled with a spring and a check plate on rebound. Good luck with your experiment. Hopefully you can overcome these issues that the other manufacturers haven't been able to. Let us know how you progress.
  2. With such a big bleed hole, the shock will also struggle to build damping, even with a really stiff stack.
  3. My Motorex rep told me about it on his last visit. I ordered it and have it in front of me now, but am yet to use it. Any motorbike shop that deals in Motorex should be able to supply it, although it wont be in their catalogue, so you'll need to get your local guy to call their Motorex distributor. Edit: Now that I look into it, it might only be new to the motorcycle division, as it apprears it may have come from the automotive side of the company. Its also called FETT 190 EP. https://www.motorex.com/en-us/car-line/grease/fett-190-ep/
  4. There are a few special tools required. There is a piston holder tool which is used to set the height of the piston after bleeding. It is important to get the piston height set correctly, so that you can install the spring and end cap to ensure proper pressurisation of the oil. Remember that this damper is like a twin chamber fork with an ICS. The other, and more important tool, is the vacuum machine adaptor. I bought the genuine Ohlins part and then changed the end threads to work on my RaceTech vac pump. I can't comment on hand bleeding it, because I've never tried, but I do know it would be much much harder than a Scotts damper. Whats your email address? I can send you the manual.
  5. I can just make out the part number on the Motorex grease. It is 300743, which is their old grease. This is good for most applications, but not the air seal. The new lithium EP grease is 300734. This grease has only just been released, so wouldnt have been available when 707 produced their video. I have no idea what grease they used for the air piston seal in their video.
  6. Motorex have a new lithium based greased which is recommended for the WP AER fork.
  7. Mostly I use a feeler gauge in one side while holding the other side of the shim stack down with my fingernail, to make the shims parallel with the piston. Repeat at 180 degrees.
  8. On 99% of bikes, the compression face shims are a larger diameter than the rebound face shims. There will be a matching difference in the piston port sizes. One exception to this rule that comes to mind is the early CR500's.
  9. I've tried both techniques and much prefer the feeler gauge method. I feel there is less room for error by taking one measurement compared to taking four separate measurements and calculating. I also think that a feeler gauge measurement is an actual measurement of the final build taking into consideration any compression or stretching of materials, any imperfections in casting/machining and is a great method for ensuring quality control.
  10. What do you think is causing the difference between your calculated and measured float?
  11. From my experience, I think you are still too light on compression and rebound damping. The stock shock is very soft and springy. I don't think you are packing in the whoops, but are just bottoming out. On the attached dyno graph, you can see the stock shock (in green) has very little damping everywhere, both compression and rebound. In comparison, the Cogent Mojave shock (in blue) has more LS comp damping and a little more HS comp damping, but a good healthy amount of rebound damping. On the other hand, the RaceTech shock shaft (in orange) has even less LS rebound damping than a stock shock, but then really ramps up as velocity increases. Your changes are a step in the right direction, but I think you need to go further. My simple suggestions would be to increase the diameter of the compression clamp shim and reduce the rebound crossover thickness to 0.10mm. Remember, if you don't have much compression damping, you cant run much rebound damping...
  12. Terry, It was from a Ducati Monster and as you know, road bikes aren't my strong point. Like you, it is the softest rear shock I have ever dyno'ed. The only other shock that has measured softer is the front shock from a R1200GS. I didn't have the opportunity to view this bike working on the track. I only had rider feedback, which would have steered me in the wrong direction. The dyno allowed me to view its performance here in my workshop without the bike, without a test track and within my tight time schedule.
  13. Here is a great example. I had a customer drop in a shock from a bike I had never worked on before. Customers complaints were "its too stiff and too harsh". The spring measured well and sag settings confirmed it was good for the riders weight. So this indicated that the issue was damping related. A common thought would be to soften the shim stack to reduce damping and given that I had never tuned one of these before, that is a direction I would have considered. Instead, I dyno'ed the shock and observed that it was very soft. Stock is in red. I then figured that the shock was "riding on the spring" and this undamped action was providing the harsh sensation. So I went the opposite direction and added shims to increase both comp and rebound damping. Revalved shock is in blue and as you can see, I have increased compression damping by 400%. This took me a few revalves, with dyno runs each time, to get it to this point. My customers feedback is that it is now much plusher and more controlled. Sure, I could have tested and tested and tested but this was impossible because I didn't have the bike. I could have revalved and delivered it to my customer for him to test before returning it over and over again until he was satisfied, but he would eventually grow unhappy with this process. I'm sure it could be improved even further, especially after getting some rider feedback, but the dyno allowed me to get it close enough that the rider was happy first attempt, provided positive feedback and hasn't returned for a change. I couldn't have delivered these sorts of results without the dyno.
  14. I'm one of those guys that has purchased a dyno recently. While I won't beat my chest over it, I will spruik the benefits. It was damn expensive (for me), but it has been worth every cent. Obviously there are plenty of good businesses around without dyno's and they have plenty of happy customers. Good settings can be developed through a thorough testing regime with quality test riders. Where the dyno excels is to help highlight issues that are hard to pinpoint while riding, to give a direction to head on new models, gain an understanding of what is causing the customers complaints, getting a setting very close before going to the test track, filtering out placebo from test rider feedback or to ensure consistency which is especially important for customers who send their shocks in and aren't available to test ride on site. Much like Terry's latest revelation, for me, the dyno has disproved more theories than I care to admit. It seriously makes the last 10 years of suspension tuning feel guess work.
  15. Spot on. An RSV with a 2.4mm hole will provide no change to the bleed until the rebound clicker is outside the normal working range. An RSV with a 2mm bleed hole will have little effect with the clicker less than 10.