IIRC the stock springs are also progressive springs. I have a few Supersports, and generally found them soft at the front and too hard at the back.

Don't over think it, speak to s good suspension guy and get the right springs for you weight and riding style. It's one of the cheapest best investments you do to your bike, getting the suspension set up properly.

 

Not an Ie but I rebuilt the forks on my 95 ss with racetech springs for my weight and it was a night and day difference. On such an old bike I can’t really say if the oem progressive rate sorings were just old and shot or crappy to start, but the race tech springs were well worth the dollars and really transformed the ride.

Cheers


Sent from my iPhone using Tapatalk

 

Yes, the front springs are too light. Racetech list a .95 spring which is a drop in. I just put some in my 93 and they are perfect for me 240lb. lardage.

 

Racetech .95 205lbs with gear on.

 

I've used Racetech fork springs on several bikes (none of which were Ducatis). Excellent improvement. I'm at 170 or so dry weight (haaha) and about 200 or so fully decked. Check in with them. They'll want to know all of that weight stuff, style of riding, what bike you have, bla bla.

 

the oem spring is a dual rate part that goes from 0.6kg/mm to 0.9kg/mm at about 3/4 travel - crap for most people. cutting the tight wound section off makes them a linear 0.9 and works well, or buy new springs to suit.

 

Thanks Belter.
When cutting the OEM springs, are you just replacing the cut off portion with a spacer that is equal to the length of the cut off section, or does it get pretty involved with determining spacer length so that you end up in the middle of the adjustable preload range? I’m guessing it’s going to vary with the weight of the rider?

 

Thanks guys- I have been messing with suspension settings for over a week and realize now that I’m going to have to do something to get the springs sorted out first. I’m expecting I’m going to need a rear spring for the Ohlins shock as well.

appreciate your input!

Dave

 

While cutting IS an option I would not recommend that direction unless you are fine with taking things apart a few times to get it right. Best bet is to buy springs all ready made in a correct rate for your weight and set preload. There are spring calculators so you can find your rate after cutting but it is more complicated than just changing with known good springs.

I still find it funny that people expect the bike manufacturers to make a bike for their specific weight. Bikes are a compromise made for the entire world and needing to cover an impossible weight range, this is difficult at best and a major reason why changing springs on most bikes should be job #1. Yes there are some that are closer than others but those are few and far between, majority of bikes I have seen over the years are all under sprung often with progressive or dual rate springs which is nothing but an admission of guilt.

With used bikes there is also always a chance that a prior owner has already changed springs so either way check sag and check preload to see if the springs you have are close or if you are looking for different function. If I find progressive or dual rate springs they are simply tossed unless straight rate springs are not available, in those cases I may cut, change for stiffer progressive or dual rate springs or have some made.

 

Presumably this bike has a 41 mm fork, making springs much harder to find.
Cutting these springs is easy, it's very obvious where the rate changes. I've done that on a set of springs for 43 mm Showas. I think they ended up at appr. 8 N/mm, Which is the linear rate of the stiffer part. Might still be a bit soft for 200 lbs, though ...

 

race tech makes springs .80-1.0

 

The Race Tech online spring calculator is giving me .9 for an old guy who is an intermediate canyon rider who is not going to track the bike. I'm going to call them next week about getting some new springs. If I'm reading the website correctly, I'm going to have to install spacers even with their new springs.

Is this Showa fork really so crappy that people are swapping in GSXR cartridges? For the money, are the Race Tech Gold valves a better way to go than the GSXR cartridges, or do you think it is a toss-up?

I've got a lot to learn about modern (upside down) forks- the last forks that I dealt with were on my Norton Atlas and all I could do was install a spacers and change the fork oil weight on the budget that I had back then....

Now, I live right on a canyon road, and though I don't get even remotely crazy on it, I'd like to get this bike dialed in as best as I can, in order to get more enjoyment and safer riding out of it.

Thanks again for all the input. It's been 25 years since I hit two deer at night doing 50 mph on my Moto Guzzi Eldorado, causing me to lose my nerve to ride again, until now.

 

Is this Showa fork really so crappy that people are swapping in GSXR cartridges? For the money, are the Race Tech Gold valves a better way to go than the GSXR cartridges, or do you think it is a toss-up?

You can check. I had a '97 900SS, and it was very obvious that the there were major problems with it... adjusting the rebound affected the compression circuit - or vice versa, I can't remember but it made it impossible to adjust compression and rebound damping independently so you could never get it just right. I did the GSX-R swap and did a full write-up on it here

Suzuki fork internal conversion

Close the compression damping adjustor all the way. If you can still compress the forks then fluid is leaking through the rebound damping circuit and you have the defective forks.

Changing the valving may or may not help depending on whether it's just a new shim stack or replacement of all the internals.

 

Then put some miles on before messing with the forks, as long as they are not leaking just ride it the way it is after setting a proper preload. If you are riding smooth roads moderately you won't feel the need to spring up.

 

the showa forks suzuki fitted in the 90's were definitely superior to what ducati was using then, even for the 916, etc sbk models. just better valving, in both design and set up i believe.

the 43mm forks have the compression adjuster in the bottom cartridge retaining bolt with a large thread, whereas the 41mm carb model and gsxr use a hollow m8 (or m10?) bolt to retain the cartridge in the leg, so you can't use the gsxr cartridges in the 43mm legs without losing the comp adj. unless you go custom bolt or make them individual function in each leg. i have some gsxr cartridges i might do that to (as in pay the man who does it) to make some 41mm non adj showa a bit tricker in the bike i pointlessly waste bulk cash on.

 

It´s almost 10 years go now, but at the time we had a test&research session at Reactive Suspension in York, UK, where we dyno tested various versions of the Showa fork, and also my Öhlins R&T 43.

Below a compilation of the most relevant results, showing among other things the minimal difference the comp adjuster on the "short needle" Showa makes. "Showa Öhlins" is a short-needle Showa with an Öhlins shim kit installed:

Skärmklipp by torbjörn bergström, on Flickr

The past summer I´ve run an ST4s fork with GSXR cartridge, comparatively soft compression stack, and a midvalve with approx. 0.15 mm of float (i.e., the midvalve shimstack is not firmly bolted down against the piston check valve face. This combination is by a considerable margin the best I´ve tested so far, while supple over road irregularities I´ve so far not managed to bottom the fork out.

For the 43 mm forks, there are (or used to be, I don´t know current availability status) springs from Öhlins; I´ve used both types. You´ll need a spacer as per Belter above, and also the washer used between the spring and spacer tube on the hyper forks, to be placed in the same position between the spring and the spacer tube providing a proper base support for the spring. I hope the list comes out reasonably readable:

Description Part no Length Inner dia. Outer dia. Wire dia. Rate Stroke
Spring,Fr.fork 04745-05 240 27.5 37.5 5 10.5 140
Spring,Fr.fork 04745-10 240 27.5 37.5 5 10 139
Spring,Fr.fork 04745-11 240 27.5 37.5 5 11 134
Spring,Fr.fork 04744-05 260 25.5 35.3 4.9 10.5 145
Spring,Fr.fork 04744-10 260 25.5 35.3 4.9 10 147
Spring,Fr.fork 04744-11 260 25.5 35.5 5 11 146
Spring,Fr.fork 08748-10 260 26.2 36 4.9 10 146
Spring,Fr.fork 08790-05 260 25.5 35.3 4.9 10.5 145
Spring,Fr.fork 08790-10 260 25.5 35.3 4.9 10 147
Spring,Fr.fork 08790-11 260 25.5 35.5 5 11 146

Of course, if you use this list, check all dimensions first!

Kind regards,
Torbjörn.

 

torbjorn

i've used 04744 in the 40mm marzocchis. do they fit in 41mm showa, or do you have to remove the white plastic bump stop like with some of the racetech springs?

do you use anything to locate the 4745 inside the tube given the 1mm or so smaller od?

is the graph for the showa short needle compression with the rebound adj closed? doing the bounce test i can definitely feel a difference in comp min to max with the rebound adj at max. i was quite surprised when i then wound the rebound out a few clicks and all the comp was gone.

does the 0.15mm float on the mid valve work as a high speed comp bleed off? where is it in the leg?

 

"Is this Showa fork really so crappy that people are swapping in GSXR cartridges? For the money, are the Race Tech Gold valves a better way to go than the GSXR cartridges, or do you think it is a toss-up? "

Depends on you and the roads you ride. The valve is a high speed compression valve so sharp edged bumps, pot holes expansion joints etc. If you have smooth roads you may not notice a valve change either gsxr or gold valve. If you do have bad roads it is worth doing either conversion, I use gold valves and have for over 20 years will good results. Keep in mind the valve is still only one part of the equation the shim stack on the valve is just as important as the best valve that is stacked too stiff will be no better than your oem valve.

On the circuits overlapping (rebound and compression) ever hear of a Ohlins shock? Yes they do the exact same as the short needle in that if you add rebound you are also effecting compression, this was shown to me at Ohlins USA when I was taking a class there many years ago. Funny not many people spend the money to change this in their Ohlins shocks because it can be changed does not mean it NEEDS to be changed for average use.

Dynos, shock or engine are great. But if I "fixed" everything my dyno found on most bikes I run on my dyno everyone would be broke. Some things need fixing others can be improved, it is important to learn where that line is and understand the difference in your needs. I ride plenty of sprung and valved short needle valved bikes (851/888, supersports, monsters, ST, sport classics) and ridden vs long needle stock bikes (most superbikes) I would take the sprung and valved bike every time. Most of the gain is in the springs as they are so far off, valving will be dependent on the bumps you have.

The limited adjuster range is real but I find in almost all of the cases the rage given should be sufficient for the job required, if I can not get a adjuster to get the slow speed damping to where I want then I go inside and make a change to allow me to get there. For the majority of riders they will set the suspension once and if they do not have a major change (rider, bike weight or roads ridden) then they likely will not touch them again. This is why the non-adjustables can work just fine some times they can take more setup but when set they are good.

If you are doing the work yourself just do the springs alone and see if that is good enough for you, yes you need to spring BOTH ends to make it right. Once that is done ride the bike paying attention to the bumps and decide if the next fork seal change you will valve or do a gsxr conversion. This way you get to become familiar with the cartridge forks and setting internal preload before getting deeper into the cartridge. Some focus on making the forks "the best" and there is nothing wrong with that though it probably ends with a new set of Ohlins forks, others will simply look to make them better and that is easy from what you have.

 

Brad,

below some comments to the best of my knowledge:

i've used 04744 in the 40mm marzocchis. do they fit in 41mm showa, or do you have to remove the white plastic bump stop like with some of the racetech springs?

I have never tried them in a 41 mm Showa, and I don´t have a 41 mm leg to measure. However, a 43 mm leg has a wall thickness of 1.75 mm. Assuming the same for the 41´s, that would equal an inner Ø of 37,5. Since the 04744 has an max outer Ø of 35.5 , I´d guess it would be worth a try.
I always remove the bump stop, you gain 10 to 15 mm of useable travel by doing so, and they often break anyway.

do you use anything to locate the 4745 inside the tube given the 1mm or so smaller od?

I have not done so, so presumably there could be some contact between spring and outer leg. So far, I´ve not seen any problem. I suppose it´s well enough lubricated, and I´ve also not seen any rub marks on the cartridge tube.

is the graph for the showa short needle compression with the rebound adj closed? doing the bounce test i can definitely feel a difference in comp min to max with the rebound adj at max. i was quite surprised when i then wound the rebound out a few clicks and all the comp was gone.

The dark blue line is with both adjusters closed, with 5W Motul fully synthetic or possibly Silkolene 5W.

Many years ago when I started to investigate what´s wrong with these forks, I also did a lot of bounce testing. The pros does not take it very seriously, but lacking a dyno, what do you do…:

Bounce test Showa by torbjörn bergström, on Flickr

“R0, R2 …” etc. are the number of clicks open on rebound, “K0, K2 …” etc. are number of compression clics open. The numbers on the Y axis is the resulting amount of fork compression, using my (then ...) 59 kg and young(er) muscles to bounce the fork. As you see, it´s the same as your observation.

does the 0.15mm float on the mid valve work as a high speed comp bleed off? where is it in the leg?
Gareth at Reactive Suspension gave me the following advice:

“ …Using 0.2mm float keeps some low speed, but ramps up the high speed. 0.4mm float softens the low a lot more, but still gives a good ramp up to the high speed …”

Since I limited the float by grinding a stop washer to exact thickness, I started with appr. 0.15 mm, figuring it´s easier to grind away a few 1/100s than making a new washer.

The midvalve stack sits where the rebound check valve would otherwise be.
I forgot to make any pics, but here is one from an Andreani cartridge I did in the same manner at the same time:

2021-12-23 10.36.31 by torbjörn bergström, on Flickr

The Andreani top washer had a tall enough collar so I used that to make space for the shim stack, spring and stop washer, from left to right. The rebound shim stack is not in the pic, just the nut and washer.

Actually, I have this pic of the GSXR cartridge rod with rebound shim stack holder and the GSXR mid valve assy at the arrow point

GSXR mid valve by torbjörn bergström, on Flickr

I hope I´ve managed to clarify, just let me know if anything is unclear.
Kind regards,
Torbjörn.

 

Guys, this is incredibly useful information- thank you.

Ducvet- Great advice. Thanks.

The roads here are a real mix, but generally I find myself having to ride through plenty of not-so-smooth sections, and those are the areas where I would like to see the suspension improved- the rough patches. I would like better compliance over the ripples and irregularities- I don't have too many potholes (nothing really "sharp" edged) to deal with.

I am beginning to see the benefit of sending your forks to a specialist. I don't have any fear of disassembly and reassembly of complex things, but the thought of having to do it over and over again to get it right, because I am a green horn with motorcycle suspensions, is not motivating (at my age)..lol

I went out today and set my compression screws all the way out, along with the rebound, and then began adjusting each until I discovered the awful truth that some of you have shared above- the rebound adjustment is what is largely (if not entirely) controlling my compression adjustment, and I am beginning to wonder if the whole point of the factory "Standard settings" was to compensate for this horrible issue (or to hide it). If I am hearing you right- this isn't a "defect", it is simply a design that many are not too fond of?

I will go definitely with springs only first (front & rear), and ride it for a while.... while learning to deal with the short needle as best I can. Who knows- maybe find happiness there somewhere. But if I can't get the compliance I want on the roads where I live, I'm going to dig into these forks! I have the Ohlins rear shock, and am wondering if the fact it's 20 years old warrants checking the nitrogen charge? The bike has very low miles- 4000.

Lastly, when changing these springs (I won't be cutting them, as I don't have an oxy/acetylene setup- only mig), any thoughts on which fork oil to use for my street use? I've been reading up and 5w seems like the best bet for me, if I make no changes other than springs?

Torbjörn-Thanks for sharing all of that. Great pics.

A really great thread here (not due to me) that you guys have created. I am learning gobs. Thanks!

 

Thanks, I´m glad if my limited experience can be of help. It´s just what I have done over the years, not any absolute truth by any means. Suspension, tires, oils, .... lots of opinions.

Anyway, if you have an Öhlins shock, there´s a good chance it is pritty stiffly set up hydraulically (i.e., shim stacks) for comfort; I´ve softened the shimstacks of my Öhlins shocks considerably on all my bikes. As they come, they might be right for aggressive track riders, but for me they were all too stiffly set.

If your shock is 20 years old, I´d say it´s overdue for a service in any case, but I doubt there´s a problem with the gas pressure. However, assuming you have an ordinary, fully adjustabe pre-TTX Öhlins shock, there´s an easy way to find out if you still have decent gas pressure: Turn the rebound adjuster at the bottom of the shock. If it has clicks, you have pressure. With no gas pressure, there will be no clicks, just a lame turning of the knob.

Kind regards,
Torbjörn.

 

i use maxima 5 weight oil, which i think they call 85/150 racing fork fluid.

fork oil ratings can be a bit arbitrary, so it's best to look at the viscosity rating which is centistokes at 40 degrees c. this page gives you a good comparison of oils. Comparative Oil Weights Table - Transmoto

the maxima 5 is 16 cst. i had to do fork seals in a 900ssie last week that i'd previously cut the springs on, which was running maxima 5 at 135mm. i used the belray 2.5 weight this time, which is 9 cst. i ran the rebound adjusters in 3 clicks from 10 to 7 out (std valving afaik). will be interesting to see what he says of any difference.

 

torbjorn - love the bounce test table. hadn't thought of trying that myself. i do love a good spreadsheet.

so the mid valve is on the rebound piston as such. do you still have a normal style compression valve on the piston at the bottom of the fork? does that reduce the influence of the comp adjuster given it's not acting on all the comp flow?

i had a 900ssie in years ago that had a lot of compression damping. maybe it was when i was doing the oil change i noticed just how much it had pushing the rod down, don't recall. i could see someone had drilled out the retaining divets in the side of the cartridge, so i pulled the comp pistons and rods out and peter at promecha talked me through changing the way the compression shims on the rebound piston were ordered - which didn't make much sense to me at the time as to why the rebound piston had comp valving. i think it had a few and ended up with one maybe. certainly fixed it.

 

I have a normal compression stack at the bottom valve, but it´s considerably softer than what I´d use without the midvalve setup.

The adjuster works as normal, on the same oil volume, equal to the cartridge rod displacement volume as the cartridge rod enters the cartridge tube when the fork compresses. Incidentally, that´s the advantage of the GSXR cartridge, the 12 mm rod (as opposed to the 10 mm rod of the Ducati forks)vgives a larger volume for the compression stack to work with.

I have not tried what you describe (a midvalve type setup on an otherwise standard "short needle" Showa fork?), but that would be a way to get some compression damping without completely modifying the fork.

 

I have a normal compression stack at the bottom valve, but it´s considerably softer than what I´d use without the midvalve setup.

i don't understand what you mean. doesn't the midvalve also flow compression oil?
photos of what i had -

 

Just to make we´re using the same word for the same things: With "compression oil" I mean the oil beeing displaced by the cartridge rod entering the cartridge. This oil has to go somewehere, preferraby through the compression stack and/ or compression adjuster orifice, but on the "short needle" Showas much of it gets shorttracked through the rebound circuit. The "compession oil" does not get pushed out of the cartridge by the rebound piston.

The midvalve sits in the oil inside the cartridge and creates damping by limiting the oil flow through the rebound piston as it passes through the oil-filled cartridge. Since the cartridge is non-pressurized, there is a limit to how much damping can be created here; too much and there will be cavitation.

Consequently, the compression base valve him stack and the mid-valve are two separate and principally different methods to create compression damping.

I found this on the internet, seem like a good explanation and illustration of mid valve function.

Fk Mid-Valve Float

 

"Lastly, when changing these springs (I won't be cutting them, as I don't have an oxy/acetylene setup- only mig), any thoughts on which fork oil to use for my street use? I've been reading up and 5w seems like the best bet for me, if I make no changes other than springs? "

Keep in mind the oil will be doing 3 jobs.

compression damping = this will control dive to some extent as well as how the fork is able to absorb different impacts. Reminder a stiffer spring will also resist dive more than oem so the new spring alone should help prevent dive.

rebound damping = at odds with the compression you need the oil to assist controlling the spring on return after compression, too light a oil with a heavy spring allows it to rebound too fast. Depending on how stiff a spring you may not want to go lighter on the oil or you will need the rebound adjuster to be too far in. As a guide I try and NOT exceed 1/2 of my low speed adjuster range in either direction.

Air spring = if you have a correct spring you should not be bottoming the 41mm fork and because of this you can safely lower the fork oil level, this will set the bottoming of the fork as well as move the higher air spring area lower allowing for a better ride mid stroke.

Also be aware oils forced through tight areas with force heat up and wear out faster ie: oils and low speed adjusters that are fully in will overheat the oil faster than oils going through a larger opening. If you run thin oils and maxed out adjusters you simply may be changing oil more often but if you find a setting that works for you and don't mind the work all is good.

 

Also be aware oils forced through tight areas with force heat up and wear out faster ie: oils and low speed adjusters that are fully in will overheat the oil faster than oils going through a larger opening. If you run thin oils and maxed out adjusters you simply may be changing oil more often but if you find a setting that works for you and don't mind the work all is good.

on this, i've done quite a lot of 43mm showa adj m900ie/m1000/s2r1000 forks with cut springs and maxima 5 wt, all of which end up with the rebound adjuster fully in. i've not noticed any big change in oil condition at changes, but i'll keep in mind to pay more attention to it in future. one of them was an m900ie that was owned by a fella who weighed maybe 110kg, so i'd cut the springs down to 1.0kg/mm calculated. he finally wrote that bike off at 130,000km, and then a fella on the monster forum - nibor - bought it and wrecked it and koko64 bought the forks and fitted them to his brother's m900ie. i recall him asking me what had been done to them because they worked so well, and he didn't seem convinced by me telling him what i'd done. i know i was the only person who touched that bike from the 60k service to the last one it had at 120k. i did exactly the same thing to that owner's s2r1000 that replaced the m900ie and it worked pretty much exactly the same according to him.

 

Without fail contact Ohlins directly evem if you have other brand fork housing. They will get it right the first time. The inserts operate in a dry fork. Right fork dord one job, left another. When done you can dial the acceleration patch up or down the tire. You can wear out trhe edge before the center on a street bike if you have no 200 mile aproach rides. I do not know where you are but Henderson NC. is remarkable. Be sure you understand flat vs curved pivot and what is the best / cheapest rear shock change. TTX etc...