Member Contributer captainchris13 Posted April 13, 2007 Member Contributer Share Posted April 13, 2007 so just because i like this thread and it has some info i need for my project, ill dump this link here. http://www.peterverdonedesigns.com/damping.htm http://www.peterverdonedesigns.com/highspeed.htm He has some amazing math equations i have been looking for, AND close up pics and comparisons of different valve bodies! lotsa fun. chris Link to comment Share on other sites More sharing options...
Member Contributer thx1139 Posted April 13, 2007 Member Contributer Share Posted April 13, 2007 so just because i like this thread and it has some info i need for my project, ill dump this link here.http://www.peterverdonedesigns.com/damping.htm http://www.peterverdonedesigns.com/highspeed.htm Be sure to check out PVD's page on oil viscosity too: http://www.peterverdonedesigns.com/lowspeed.htm It's explained here how oil weight ratings are a bad way to select your oil. ISO viscosity numbers are more consistant and reliable. I'm always looking up that chart at the bottom of the page! Link to comment Share on other sites More sharing options...
Member Contributer thx1139 Posted April 13, 2007 Member Contributer Share Posted April 13, 2007 so i guess what i have to do is get rid of the bleed notches and just drilla bleed hole and try it. should i start with a 1mm hole? Might be a place to start. You can always drill it bigger afterward. Racetech advises a 1mm hole for firm lowspeed going up to 1.3 for plush. Sucks not having comp adjusters. Use a sheet of 600 grit on a plate of glass to suface the valve. Use a figure-8 motion, It must be remain perfectly flat! The trick is drilling holes in the Showa 3 port valves. It's harder than on a GV to find a place to drill! Showa used drilled bleeds on some stock valves. They drilled in from the side, just above the seal groove, going in at a 45deg angle through to one of the ports. No room for error or a wobbly drill! Link to comment Share on other sites More sharing options...
flyguyeddy Posted April 15, 2007 Author Share Posted April 15, 2007 what if i used an HMAS valve for the compression? would that work alright? or should i just bite the bulet and buy a gold valve? Link to comment Share on other sites More sharing options...
Baileyrock Posted April 15, 2007 Share Posted April 15, 2007 what if i used an HMAS valve for the compression? would that work alright?or should i just bite the bulet and buy a gold valve? I wouldn't waste the money on Gold valves if you have the 3 port honda's, they are consider high flow unlike the HMAS which have very small ports. Link to comment Share on other sites More sharing options...
Member Contributer thx1139 Posted April 16, 2007 Member Contributer Share Posted April 16, 2007 what if i used an HMAS valve for the compression? would that work alright?or should i just bite the bulet and buy a gold valve? Like Bailey said, the GVs aren't much advantage over hi-flow Showa 3 ports. OTOH; if you bought all the shims that come in a GV kit you'd end up spending the cost of an entire GV kit itself. Your idea is actually opposite of what Racetech does. Their comp valve is a 3 port hi-flow design. However, Racetech rebound valves are a 4-port orifice style piston like HMAS! (albeit with larger orifices.) Coincidentally, if you drill out the round HMAS ports to about 2.4mm, Honda valves start looking a lot like the valves from Ohlins' 20mm U.E.S. cartridge kit. I'd assume the stack on a 4-port orifice piston won't work quite the same way on a hi-flow, because fluid has a smaller area on the base shim to work against. With that in mind, I'd love to see the setup guide that comes with the U.E.S. kit. IIRC Ohlins does not alter the count (4) of shims in a stack; rather they tune by adjusting the thicknesses only. They also use thicker shims like .20s and .25s. IMHO, piston and stack configuration recieve more than their share of attention. The low-speed circuit has much more to do with the feedback and feel you get from the front end; feeling the "grit" of the road surface as one tuner puts it. Work on surfacing those 3 ports and getting a precise 1mm bleed hole drilled into each one for good low-speed compression. Try that, and go from there. Speaking of Ohlins valves, I heard the valves in newer Yamaha [soqi] 20mm cartridges are exact copies. Anyone seen em? got a picture? Link to comment Share on other sites More sharing options...
Baileyrock Posted April 16, 2007 Share Posted April 16, 2007 Speaking of Ohlins valves, I heard the valves in newer Yamaha [soqi] 20mm cartridges are exact copies. Anyone seen em? got a picture? That would make sense, because Yamaha owns most of Ohlins anyway from what I understand ! :rolleyes: Link to comment Share on other sites More sharing options...
flyguyeddy Posted April 21, 2007 Author Share Posted April 21, 2007 ok heres what i think im going to do for now. im going to face the rebound valve and install it on the damping rods with the adjsuters. i'll leave the compression valve alone, maybe do some light facing on it. install it with the shims that the bike came with and see what happens. i'll keep the HMAS valves around just in case i want to bore out the holes and make them look like ohlins valves. having spare parts laying round never hurts anyway. Link to comment Share on other sites More sharing options...
flyguyeddy Posted May 6, 2007 Author Share Posted May 6, 2007 ok i have a question: there are notches on both sides of the rebound valve. currently working on the side that has one thick shim and a wave washer. do i do both sides? the HMAS valves dont have bleed shims on both sides, do they? Link to comment Share on other sites More sharing options...
Member Contributer thx1139 Posted May 7, 2007 Member Contributer Share Posted May 7, 2007 ok i have a question: there are notches on both sides of the rebound valve. currently working on the side that has one thick shim and a wave washer. do i do both sides? the HMAS valves dont have bleed shims on both sides, do they? The wave washer side is the check valve side. That check valve seals the rebound refill ports. In compression it is open. In rebound/droop it closes forcing fluid to act against the rebound shim stack. if fluid is allowed to bypass the rebound shim stack by leaking past the check plate sealing surface into the refill ports, then that will add to the rebound bleed/soften the low speed rebound. My HMAS rebound valves were from a rebound adjustable VTR fork. The were no rebound bleed shims. Only the compression HMAS valve had a bleed shim. Got pictures of the notches? Link to comment Share on other sites More sharing options...
flyguyeddy Posted May 7, 2007 Author Share Posted May 7, 2007 actually i already sanded all the notches off of them. JUST the rebound valves. i hope that wasnt a bad thing to do! i assumed that the notches on the shim side were for low speed as well, so i got rid of them too. did i just ruin a perfectly good set of Showa 3 ports? Link to comment Share on other sites More sharing options...
flyguyeddy Posted May 7, 2007 Author Share Posted May 7, 2007 ok i went ahead and ported them bad boys out anyway, and did some to one of the HMAS rebound pistons as well. here, see what u think http://www.vfrdiscussion.com/forum/index.p...mp;#entry388466 Link to comment Share on other sites More sharing options...
Member Contributer thx1139 Posted May 7, 2007 Member Contributer Share Posted May 7, 2007 did i just ruin a perfectly good set of Showa 3 ports? I can't see anything wrong with them. :thumbsup: Link to comment Share on other sites More sharing options...
Guest Posted May 7, 2007 Share Posted May 7, 2007 Interesting discussion, :thumbsup: Eddy i changed my setup yesterday, so here is some stack data for discussion. Compression remains unchanged at - 17 x 0.4 Showa 3 port surface dressed - bleed notches removed, with 1mm bleed 17 x 0.10 16 x 0.10 (2) 15 x 0.15 14 x 0.10 C 8.5 x 0.20 11.4 x 0.4 Rebound has seen the pistons changed from the 3 port Showas and is now - 17 x 0.4 Showa HMAS 4 port, surfaced dressed and refill ports drilled out to 3mm (2.8mm may have been better for reliability as there is very little metal left), bleed indentations are not completely removed 17 x 0.10 16 x 0.10 15 x 0.15 14 x 0.15 C 8.5 x 0.20 11.4 x 0.4 These are in a 5th gen that has Ohlins springs, CBR600F2 damper rods and firestorm fork bottoms/ callipers. I find fleabay usefull as pistons are difficult to obtain cheaply and it gives me shims too use, it also lets me see whats being used in other forks. For the curious the standard stacks in the 5th gen are: Compression 17 x 0.4 Showa 3 port 17 x 0.15 17 x 0.1 (2) C 8 x 0.2 11.4 x 0.4 (2) Rebound 17 x 0.4 Showa 3 port 17 x 0.15 (2) 17 x 0.1 (3) C 8 x 0.2 11.4 x 0.4 Link to comment Share on other sites More sharing options...
flyguyeddy Posted May 7, 2007 Author Share Posted May 7, 2007 how did you go about drilling the bleed holes? that appears to be the most difficult part of using the 3 port valve. why did u switch to the HMAS rebound valve? Link to comment Share on other sites More sharing options...
Member Contributer thx1139 Posted May 7, 2007 Member Contributer Share Posted May 7, 2007 Here's where Showa locates the holes on some 3 ports: Link to comment Share on other sites More sharing options...
Guest Posted May 7, 2007 Share Posted May 7, 2007 My bleed holes on the compression pistons are as THX1138's picture, there drilled at an angle into the port, i used a cordless drill with variable speed. For drilling the HMAS fill ports i used a small pillar drill as doing it by hand I would inevitably go astray. As for the HMAS valves, well i got a badly bent set of blade forks and i thought i would try them, but the small fill ports worried me as i don't have an oil hole through the shim stack assembly for rebound adjustment at the rod bottom which helps backfill the cartridge - this is something i am working on now . I had got too the point where the front rebound wasn't quite where i wanted it and thought i would try something else. Link to comment Share on other sites More sharing options...
Member Contributer thx1139 Posted May 7, 2007 Member Contributer Share Posted May 7, 2007 My bleed holes on the compression pistons are as THX1138's picture, there drilled at an angle into the port... What's your impression with the 1.0mm bleed? With a single 17 x .10 for a base shim the comp valve must start opening very quickly. Did I read it correctly? What brand/weight oil are you using with this setup? May as well ask what tires too since I'm being all inquisitive... Link to comment Share on other sites More sharing options...
Guest Posted May 8, 2007 Share Posted May 8, 2007 My bleed holes on the compression pistons are as THX1138's picture, there drilled at an angle into the port... What's your impression with the 1.0mm bleed? With a single 17 x .10 for a base shim the comp valve must start opening very quickly. Did I read it correctly? What brand/weight oil are you using with this setup? May as well ask what tires too since I'm being all inquisitive... The 1mm bleed is better than the first attempt which was 1.5mm and was way too harsh feeling. Yes, Comp is initially soft but stiffens up quite quickly as the shims contact the clamp. I have tried various combinations (12 revalves and counting) as i try to learn how different parts of the damping circuit can be changed and seem to prefer having more thin shims where the damping is less harsh feeling rather than with fewer thicker shims. I did try changing the clamp's too but i don't think I'm good enough to notice 0.5mm through the seat of the pants dyno. Oil is Silkolene RSF Pro at 20cSt@40 - mixture of 2.5 and 5 wt, oil gap is 133mm and tyres are Diablo Corsas. The bike is used mainly on bumpy twisty roads and is now a lot better than the soft wallowing mush that Honda provide as standard. THX1138 I think you mentioned the relationship where 1 x 0.15 = 3.4 x 0.10, but is there a corresponding relationship when you start reducing shim diameters? Link to comment Share on other sites More sharing options...
flyguyeddy Posted May 9, 2007 Author Share Posted May 9, 2007 i would like to copy your setup. where did you get those .15 shims from? what fork comes with them stock? Link to comment Share on other sites More sharing options...
Member Contributer thx1139 Posted May 11, 2007 Member Contributer Share Posted May 11, 2007 The 1mm bleed is better than the first attempt which was 1.5mm and was way too harsh feeling. Yes, Comp is initially soft but stiffens up quite quickly as the shims contact the clamp. I have tried various combinations (12 revalves and counting) as i try to learn how different parts of the damping circuit can be changed and seem to prefer having more thin shims where the damping is less harsh feeling rather than with fewer thicker shims. I did try changing the clamp's too but i don't think I'm good enough to notice 0.5mm through the seat of the pants dyno. Oil is Silkolene RSF Pro at 20cSt@40 - mixture of 2.5 and 5 wt, oil gap is 133mm and tyres are Diablo Corsas. The bike is used mainly on bumpy twisty roads and is now a lot better than the soft wallowing mush that Honda provide as standard. THX1138 I think you mentioned the relationship where 1 x 0.15 = 3.4 x 0.10, but is there a corresponding relationship when you start reducing shim diameters? Hmmm... it's rather contrary of expectation for the 1.5mm bleed to be more harsh than a smaller 1.0mm. "Sticktion" may have also contibuted to harshness. Do you have before/after measurments to compare? On a shock dyno a large bleed would appear as the low-speed part of the curve being flatter, then suddenly hooking upward into a sharper transition with the shallow high-speed slope (-as the bleed "packs up" with fluid and the stack blows open). A smaller bleed graphs a steeper low-speed slope with a more rounded transition. Maybe it's this smoothing over of the "knee" of the curves giving the perception of less harshness... just thinking out loud here. Also, shims shouldn't be "topping out" against the clamp shim. If we are applying terms correctly, the "clamp" is the small diameter shim at the top of the "christmas tree" of larger shims. Usually around 8-10mm. (in shocks, Penske calls this shim the "constant".) When the stack is tightly secured by its fastener, the clamp shim forms a virtual solid column through the center of the stack. By varying clamp diameter, the overall stiffness of the stack is altered. Often employed as a fine-tuning variable for the stack. There is no equivalance factor for different shim diameters that I am aware of. Graduated diameters are chosen to effect the shape of the hi-speed portion of the resistance curve, rather than relative height of the curve (stack stiffness). A straight stack of shims will deflect at a linear rate. By tapering the stack, we get a progressive stack spring rate. The large diameter shims bend first, starting with the base shim lifting off the valve at its outer edge. As the base shim is pushed further open, the next smaller shim adds its resistance, then the next smaller, and so-on. The stack opens by progressively curling away from the valve, from the edge toward the center; stopping at the outside diameter of the clamp shim. The clamp should not bend, it's there to set the fulcrum point for the other shims to bend around. Moving the fulcrum away from the outside edge of the valve (smaller diameter clamp) increases the leverage that the fluid has on the stack; so its overall stiffness is reduced. With a larger clamp the opposite is true. Since deflected-disc valves are inherently digressive, tapered shim stacks allow building some progressive nature back into the valve. Initial opening can be made softer without sacrificing too much resistance at higher shaft velocities. Selecting the location within the stack that shim diameters are reduced is a tool for shaping the slant of the hi-speed curve. Hope this at least makes some sense... I'd attach some screen shots from the Penske or Ohlins manuals which I have in .pdf form; but that's all on my other PC which is 800 miles from me at the moment. They contain graphs that make a way clearer illustration than any of my meanderings do. Link to comment Share on other sites More sharing options...
Member Contributer thx1139 Posted May 11, 2007 Member Contributer Share Posted May 11, 2007 where did you get those .15 shims from? what fork comes with them stock? Racetech sells shims by the 10 pack. You have to dig around their web site to find them. Racetech shims If the link doesn't work, click "Search by Part #". under "Keywords" enter "SH06". Or try this page. Link to comment Share on other sites More sharing options...
flyguyeddy Posted May 12, 2007 Author Share Posted May 12, 2007 this thread is very informative! thx you are a wealth of information. Link to comment Share on other sites More sharing options...
flyguyeddy Posted August 11, 2007 Author Share Posted August 11, 2007 alright im resurrecting this one for another question. i am going to start to put my stuff back together. im going to use OMO1's stacks and specs. when i drill the bleed hole for the compression valve, do i just drill one hole, or 3 on each of the trapezoidal ports? also, he is using a non-adjustable rebound damping rod. i have a rod from a superhawk. is this going to make a difference in anything having to do with the shimstack? i dont think it will, being as all the rod is for is slow speed adjustment, but i cant be for sure. also, i am pretty sure that the internals for the superhawk are shorter than what comes in the VFR. do i need to be worried about that? should there be any binding or topping out issues that i will have to deal with? i sure hope not. i know that the F3 forks are shorter than what we have and people put those into VFRs all the time, so maybe i alright. Link to comment Share on other sites More sharing options...
Member Contributer thx1139 Posted August 15, 2007 Member Contributer Share Posted August 15, 2007 alright im resurrecting this one for another question.i am going to start to put my stuff back together. im going to use OMO1's stacks and specs. when i drill the bleed hole for the compression valve, do i just drill one hole, or 3 on each of the trapezoidal ports? also, he is using a non-adjustable rebound damping rod. i have a rod from a superhawk. is this going to make a difference in anything having to do with the shimstack? i dont think it will, being as all the rod is for is slow speed adjustment, but i cant be for sure. also, i am pretty sure that the internals for the superhawk are shorter than what comes in the VFR. do i need to be worried about that? should there be any binding or topping out issues that i will have to deal with? i sure hope not. i know that the F3 forks are shorter than what we have and people put those into VFRs all the time, so maybe i alright. 1) Drill just one hole in each comp valve. 2) Same stacks for adjustable rebound fork. Stacks are high speed, bleeds and/or adjusters are low speed. 3) I swapped adjustable SuperHawk guts into my '96VFR fork. IIRC, I used the whole S'hawk cartridge. Its body has the top-out spring located further down, to keep the adjustable rod/reb' valve from topping out against the bearing at full extension. I'm afraid many people overlook this when contemplating F3 adjuster conversions. If you have access to a lathe you could probably cut new grooves in the VFR cartridge body for the same result. Link to comment Share on other sites More sharing options...
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