Upgraded suspension finally!

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Jan 30, 2016
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8892
Just got done upgrading my suspension a few days ago. setup went like this:

Front
-Sonic 1.2 springs (increased length of spacers the same amount on both sides, 1 supplied washer on top of left spacer)
-3/4" preload
-10w oil (harley type E, cause that's what I had kicking' around)
-tapered roller steering head bearings
-new seals and wipers.

Rear
-Progressive 465, rebound on #4

Rider sag is set at 1.25" both ends (front is a little less). Man, what a difference. There's VERY little brake dive, even at higher speeds. You can definitely feel the road, but its way more controlled. Going around corners is probably the most dramatic change. It takes less effort to pick the line, and the bike feels like its on rails. Huge difference at high speed. With the stock suspension it wallowed pretty bad, and you really had to pay attention. Its like it goes around corners by itself now. It's different enough, to where I gotta get used to the feel again.
I plan on putting a couple thousand miles on it to break in the springs a little bit, and then I might decrease the preload a little bit. Its a little too solid maybe. We'll see how it feels. Super glad I finally did it. C'mmon warm weather :)

Frank
 
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8901
Good on you Frank.

I've got the same shock (set on #2 damping) but have gone a different route up front, where I have put a second cartridge damper from a right leg into the left, and removed the damper rod, then replaced the cartridge valve bodies with some higher flowing units and re-shimmed, so the front end is now basically the same as an ST1300 that has had the Gold Valve treatment (or any other modern conventional cartridge fork) and the anti-dive is disabled.

I did buy and try some 1.1 kg/mm Sonic Springs but these were too firm for me (190 lbs, no luggage or pillion), and as I had some spare 0.9 kg/mm springs sitting around I slotted those in, and think they are just right for me. I still have a little work to dial the fork in (I want to increase the rebound bypass holes from 1.0 to 1.3mm and replace the fork bushings at the same time) but its pretty close now, using a C32 compression stack and RH16 rebound stack, and 5W oil at 150mm.

With newish tyres (Bridgestone BT020 rear and Pirelli Angel ST in front, stock sizes) I find the ST is a really neutral and trustworthy handler; the front end stability on rough roads is great; certainly miles different from the slushy wallower that I originally bought. Here's some proof:

[video=youtube;iiCg7pE5oEU]https://www.youtube.com/watch?v=iiCg7pE5oEU[/video]
 
OP
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That's interesting....I hadn't thought of putting another cartridge in the left side, that seems like a good idea! Now how did you go about revalving it? Doesn't sound like you used gold valves...

Only thing I could find wrong with the video, is you (and everybody else) was driving on the wrong side of the road......;)

Frank
 
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8901
I did not use Gold Valves but just as easily could have done so. The valves that I used came from Daugherty Motorsports and are very similar to Gold Valves in design. What I've learned about Honda suspension is that there is a lot of interchangeability between Showa parts, as they use the same basic dimensions of fork cartridge (10mm shaft, 20mm id cartridge) so you can swap parts or knowledge from one bike to another. As an example the ST cartridge uses the same dimension valve components as my VTR1000F and VFR800F, although the cartridge tube and the damper rod are ST-specific to suit the fork length and stroke. The ST also uses an internal top-out spring within the cartridge rather than the external springs of most other Showa forks.

The stock cartridge valves are good from a flow point of view (big ports) but have fixed bleeds machined into the shim sealing face, 9 bleeds on compression and 6 on rebound; for reference, a sportier bike would have 3 bleeds in each position, and this is where the ST gets its plushness but also loses out on some chassis control. Bleeds are ports that are always open and provide mst of the flow control until the oil flow is sufficient to start opening the shims. My experience is that there is always a trade-off when trying to improve chassis control. The new valves probably don't flow much more oil through the main ports but use much smaller bleeds which tightens the chassis feel a lot.

On my ST I removed the old damper rod from the left leg, and simply installed the second right-leg cartridge in it's place, using the same bottom bolt and sealing washer. The one part I omitted is the oil lock piece which is the silver cup on the end of the cartridge which provides bottoming resistance at full travel, as this would not fit the left leg, probably due to the antidive parts. To date and with lots of hard use I haven't missed this part (no noticeable bottoming). I used some spare VFR800 fork caps to connect to the damper rod and also provide preload adjustability.

If you want any more detail, just let me know.
 

John OoSTerhuis

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I'd really like to try your suspension setup, Terry.

Nice video! I was concerned about hanging your head over the center stripe, though. Just a friendly observation. Sorry, a pet peeve of mine.

John
 
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I wonder if a guy would gain much by just doing both cartridges. And the preload adjustment caps would be pretty nice to add. So the VFR800 caps are the same diameter and thread, with a preload adjustment? I looked on their site for the valves..are they the $205 ones they have listed under the performance section, or do you have to send them your cartridges as well?

I kind of figured Honda/Showa parts might have a lot of interchange going on...I know the parts in my FXDX cartridges look to be about the same dimensions/setup as in the Honda anyways.

Frank
 
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I'd really like to try your suspension setup, Terry.

Nice video! I was concerned about hanging your head over the center stripe, though. Just a friendly observation. Sorry, a pet peeve of mine.

John
That is a bad habit of mine John that I'm trying to cure. Fortunately the oncoming traffic usually hugs the inside as well. For some mental reason I struggle to ride far enough into a right hand bend before leaning in, so I end up starting some bends too close to the centre line, where I'm perfectly happy to go far into a left hand bend before turning in. Probably need to slow down my corner entry some. I do find the slower steering of the ST a little disconcerting and that may be part of my coping mechanism.

With cartridge dampers you can set up the forks any way that you want, as there are plenty of variables to investigate, specifically the bleed hole diameter, number of face shims, and the supporting shim configuration, and of course the rebound and compression are (mostly) independent of each other. I don't pretend to be an expert, just an enthusiastic amateur who doesn't mind experimenting a little, and I have played around a lot with forks in the last couple of years. I have started with the set-ups provided by vendors (e.g. Racetech) and then systematically varied a piece at a time to understand the effects, and have read a fair bit as well. The recommended setups are pretty close to optimum but in my view a little heavy on the compression side of things if you spend much time on rougher roads.

To be honest the set up that I now have in the ST11 pretty closely mimics what I use in my other two bikes as well, although with those I have the luxury of externally adjustable rebound bleeds (stock on the VTR, and I fitted my VFR with CBR600F4 forks) and compression bleed in the VFR as well. I need to work through the maths of the external adjusters (thread pitch and taper on the needle) so I can calculate the bleed areas in use and compare these to the fixed bleeds in the ST.

I'm happy to share any information that you want.
 
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In my opinion the damper rod in the left leg is a compromised design but a lot cheaper to install than a cartridge, and I think Honda were still trying to milk some marketing $$ out of the antidive system. If you were to get a Racetech kit for the ST11, they supply a Cartridge Emulator that takes over the compression damping and behaves more like a cartridge, and modify the damper rod so no compression work is done.

There are certainly examples of bikes where all the damping is done in one leg and the other just carries a spring and lubricating oil. Once you bolt the axle in tight, the fork acts like a single unit so uneven forces in each leg won't make any difference.

VFR800's and 750's from 1990 to 2001 inclusive used 41mm forks that would provide suitable adjustable caps. My caps are from my 1999 VFR (same model 1998-2001 incl). The 2002 onwards VFR800's use a 43mm cap that should work with 43mm fork ST1100's.

I have a relationship with Jamie at Daugherty and so he has been comfortable supplying me parts, IIRC the last lot of valve bodies that I bought were US$60 for a pair of compression valves and $75 for a pair of rebounds, and $15 per pair for shims. So all up they would be $160 for all the parts needed.
 
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Do you take the cartridge apart to change shims, or is that a function of the the aftermarket valves? And the holes...I assume you can only change the bleed holes by drilling them out?

I agree Honda only used the dampers in one side to save money. I'm also in agreement that once the axle is tight, it all moves the same. That's why I wasn't sure if putting a cartridge in both sides would be enough to notice a difference since one side is already doing the work...

Frank
 
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Well the damper rod does do some of the damping work in the left side, but because it relies on orifice style restriction, the damping force increases at the square of the velocity, which means on fast bumps you get more shock transmitted, and on slower bumps you get not much control because the velocity is low. So I expect you would get more reduction in transmitted jolts by disabling the damper rod compression, which is what Racetech advise by drilling a whole lot more holes in the lower part of the rod, and leaving the rebound one-way assembly in place. To replace the loss of left side compression control, the right cartridge might need to have the compression shim stack beefed up a fair bit.

Yes you have to disassemble the cartridge to change shims. Once the cartridge is out of the fork, push the compression valve inwards to expose a small circlip, after that is picked out then push the compression valve out by pushing the damper shaft in, and right through the cartridge. The first time you do this peening at the rebound nut needs to be filed off (2 minutes with a hand file), then the retaining nut or bolt is unscrewed and the valve(s) can be disassembled.

The aftermarket valves (e.g. Racetech or Daugherty) differ in the port sizes (usually larger than OEM) and the lack of a predetermined bleed hole. But otherwise they are just simple solid parts of aluminium.

With some practice I can usually strip, disassemble, modify, reassemble, fill oil and have the bike back together in less than 2 hours.
 
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I like the idea of messing around with the valving a lot. There's also a RH fork on sleazebay I have my eye on. How do you go about figuring out the shims and where do you get them, or are they just washers? I weigh almost a 100lbs more than you, in addition to the wife (110lbs) riding on the back usually, so the valving would be drastically different in my case I think.

I've been in a lot of different forks over the years, but haven't really had much experience in actually 'tuning' them. I feel like I grasp the concepts pretty well, just not sure how drastic different adjustments are going to affect compression and rebound. Plus as said, I'm probably heavier than most. I know it's going to be subjective, and I'll have to play around with it, but where would you start out? I'm leaning toward trying the dual cartridge setup without the racetech valves, although it might be better to put them in..

As as it sits right now, the compression on the front is a little harsh over big bumps, but I've only been able to put about 100 miles on it (yesterday, lol), and the springs need to settle a bit. My preload is prolly a little on the tight side...

Frank
 
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Originally Posted by Bueller
I weigh almost a 100lbs more than you on top of the wife.
Ha ha, that caught my eye too!


How do you go about figuring out the shims and where do you get them, or are they just washers?
No, you need specific suspension shims, especially you will need plenty of 17mm OD x 0.15mm thickness. My starting point has been two of these on the compression valve, and 5 in the rebound. Plus a tapering selection of supporting shims. Take look at the Racetech instructions here: https://www.dropbox.com/s/c3t3c8ygt00dnxx/Gold valve compression installation.pdf?dl=0
and here https://www.dropbox.com/s/cuen74nrsz3dck6/Racetech%20Rebound%20Gold%20Valve%20Instructions.pdf?dl=0.

In essence I am using the C32 compression stack, and the rH16 rebound stack, with 0.9 kg/mm springs, and 150mm oil depth with 5W. I'm not suggesting that is perfect for everyone but it feels like a good sport-touring setting to/for me.
 

ST Gui

240Robert
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Bueller said:
preload adjustment caps would be pretty nice to add
I had a set of air adjustment caps on my GL1000. There was a Schrader valve on one with a crossover tube to the other fork that had an air gauge on its cap. It was filled with a fat syringe that screwed onto the valve. This really improved the ride without me having to mess with springs and spacers. I may have gone to a lighter fluid as well.

That arrangement wouldn't work with my risers (unless maybe a 90? valve could be shoehorned in there). Being the unsophisticated rider I am this would be an easy way to get a little bump relief. Stiction is supposedly a problem with this approach but I never noticed it on the GL and probably wouldn't on the ST.
 
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TerryS-
What are you running for sag numbers?

Frank
At the front with me on board, approx. 38mm. At the rear I've never measured rider sag, but I did set the static (unladen) sag to a very unscientific "about" 6mm, by eye rather than tape measure...Wound in a lot more preload than the shock arrived with anyway.
 
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Good on you Frank.

I've got the same shock (set on #2 damping) but have gone a different route up front, where I have put a second cartridge damper from a right leg into the left, and removed the damper rod, then replaced the cartridge valve bodies with some higher flowing units and re-shimmed, so the front end is now basically the same as an ST1300 that has had the Gold Valve treatment (or any other modern conventional cartridge fork) and the anti-dive is disabled.

I did buy and try some 1.1 kg/mm Sonic Springs but these were too firm for me (190 lbs, no luggage or pillion), and as I had some spare 0.9 kg/mm springs sitting around I slotted those in, and think they are just right for me. I still have a little work to dial the fork in (I want to increase the rebound bypass holes from 1.0 to 1.3mm and replace the fork bushings at the same time) but its pretty close now, using a C32 compression stack and RH16 rebound stack, and 5W oil at 150mm.

With newish tyres (Bridgestone BT020 rear and Pirelli Angel ST in front, stock sizes) I find the ST is a really neutral and trustworthy handler; the front end stability on rough roads is great; certainly miles different from the slushy wallower that I originally bought. Here's some proof:

[video=youtube;iiCg7pE5oEU]https://www.youtube.com/watch?v=iiCg7pE5oEU[/video]
Very very offtopic, but that video was hard to watch in northern EU. :)

Does anyone have Bitubo rear shock and what is the point in disabling the anti-dive system?
 
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Very very offtopic, but that video was hard to watch in northern EU. :)

Does anyone have Bitubo rear shock and what is the point in disabling the anti-dive system?
I have nothing personal against anti-dive, but there are better ways of generating damping forces than the damper rod system, specifically a cartridge damper. By fitting the cartridge, the antidive is inoperative as it is designed to provide additional compression damping restriction to the damper rod. Decent springs and compression damping can yield a more compliant fork when braking over bumps.
 
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