ULEWZ
Well-known member
I had the GP valves done on my FZ1 years ago. I forgot about that, but will see how much that would cost.
Trying to decide between shocks, need some advice.
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ULEWZ
Well-known member
What rider weight are the stock springs set up for? I am 180 lbs and they seem ok.
SkooterG
Purveyor of Crooked Facts
Well, I hope to get to one soon. I have been busy as hell since the install. I took some photos and asked some questions but was not as involved with the forks as I would have liked to be. While he was playing with the forks, I was installing the new Ohlins shock. Still, he did show me a side by side comparison of the stock piston and the RaceTech piston.My comment was based on (1) what I have been told, and (2) pictures of the Racetech kits I have seen online, but if that isn't correct then I would like to know the answer.....and maybe it varies depending on the bike, kits for some bikes and new pistons for others. Didn't you just do the Racetech upgrade on your 09? If so, what did you get? Did you take pictures of the upgrade? And still waiting for your ride report......
Reader's Digest: I went from a good stock suspension but soft with limited ground clearance to a good aftermarket suspension that is too firm with much better ground clearance but too harsh. But I have just started playing with adjustments and so far I am improving on it. I hope to be able to get it where I want it.
SkooterG
Purveyor of Crooked Facts
Ok because you don't know any better. The answer partly depends on the type of riding you do. But if you are going to get an aftermarket shock which I guarantee will come with a heavier spring, you will want heavier springs in the forks.
Have you ever taken any SAG measurements?
MCRIDER007
Well-known member
If you believe the RaceTech spring calculator, the stock springs are ideal for a 115 lb rider although I think they are probably sufficient for a 150-160 lb rider, however the high speed compression damping consists of one spring loaded shim that is either open or closed and doesn't flow much oil when it is open. Revalving would be a big improvement for any weight rider.
MCRIDER007
Well-known member
OK, I stand corrected on the RaceTech pistons...at least for the FJR. I just looked at the OEM damping pistons and it does look like it would be very difficult to rebuild those pistons since they use rivits.
Is your harsh ride coming from the Ohlins? I think that while Ohlins offers different springs, one size fits all when it comes to damping, and they tend to set their shocks up for high speed track use rather than normal street riding. You should try turning the compression damping to full soft and if you still have a harsh ride it may be necessary to have it revalved.....which GP Suspension told me they had to do a lot with the Ohlins they sold.
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Assume that you are talking about your own bike (a second gen), the stock fork springs are .85kg/mm.
Race Tech suggests a .917kg springs for a 180 lb rider, so you aren't all that far off.
On the back, the shock spring rate is 9.3 - 12.7 kg/mm (soft - hard) and they suggested 18kg for a 180 lb rider.
PS - The Race Tech calculator says the fork spring is .80, but that is just the 1st stage of the dual stage 1st gen springs.
Race Tech suggests a .917kg springs for a 180 lb rider, so you aren't all that far off.
On the back, the shock spring rate is 9.3 - 12.7 kg/mm (soft - hard) and they suggested 18kg for a 180 lb rider.
PS - The Race Tech calculator says the fork spring is .80, but that is just the 1st stage of the dual stage 1st gen springs.
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SkooterG
Purveyor of Crooked Facts
Yeah, guess I should have done more research on the shock. You're not the first to tell me similar about a 'one size fits all'. I know I ordered a specific spring with this shock that was one size stiffer than their 'normal' and that was based on conversations with one of their corporate techs. I will say I got such a smoking deal on the Ohlins I don't think I would have (can't afford) gone any other route however.
I still have a lot of playing to do but I did back the shock's compression off only two clicks and things got better. When I get a chance, hopefully sometime this week I will back it off fully and play with it more. Hope to get some friends together and do proper SAG measurements also. Supposedly my rear SAG right after install was only 10mm but I think that is wrong. Feels like more to me. I think he measured wrong. It had been a long day and we both had other fish to fry. Obviously if it is only 10mm I have a spring problem too.
For fork rebound, I still have to play a little but I went from 1 or 2 clicks out with stock, to almost the full 17 clicks out with the new RaceTech forks.
SkooterG
Purveyor of Crooked Facts
I'm not so sure about the calculator. I specifically had 1.1 springs put in my 09. I am a 175-180 lb rider (without gear). Why? That is what is in my 04 forks with Traxxion Ak-20 cartridges and I really like that suspension. I asked the tech about it and they said the calculator recommends on the softer side since it is a sport-touring bike. That being said, the tech told me after the install that for me he thought I should have gone with the 1.0 springs.
MCRIDER007
Well-known member
If the shock is over sprung and/or over dampened, you can trying putting extra weight on it (girl friend, fuel cell, keg of beer, big trunk, full saddlebags) and see if that improves the ride.
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MCRIDER007
Well-known member
What is your source that the GEN1 springs are dual rate and the GEN2 stock fork springs are .85kg/mm? I still have the OEM springs from my 05 and they are not dual rate, they look like they might be slightly progressive but the "progressive rate" would not kick in until the very end (if at all) of the stroke. I have seen what appeared to be the exact same springs in a 04, 06, and my 08.....however the GEN2 models do have slightly different part numbers.
The Wilbers springs that I bought in the January 06 group buy are dual rate and 15mm longer than the OEM springs but when GP Suspension tested them the rate was .80.
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The factory service manual says they are:
Early 1st Gen ( thru '03)
Later first gens ('04-'05)
2nd Gen
As I said previously, I've never had the stock springs in my bike as long as I've owned it, so I've never actually seen these before first hand.
But, I'd have to figure that the FSM is right?
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MCRIDER007
Well-known member
I can't argue with your choice of source but the FSM is saying that the GEN1 springs are .80 KG for 3.58 inches and 1.0 KG for the remainder of the stroke so I have to ask myself.....do I believe the FSM or my own eyes......and the springs that came out of my 05 are NOT (opps....my bad, see comments below) dual rate. I can believe that the GEN2 springs may have been bumped to .85 because that would not be obvious just looking at them and would explain why I have always believed the GEN2s handle better than the GEN1s but it sure seemed like more of a difference when I transferred the GP Suspension .95 springs to my 08.
Color me confused at this point......at least as to what the OEM springs actually are. The solution to the handling deficiencies is still the same.
Color me confused at this point......at least as to what the OEM springs actually are. The solution to the handling deficiencies is still the same.
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SkooterG
Purveyor of Crooked Facts
Trying to get the correct info.............
I assume the spring rate info is correct, but how about suspension travel?
For the front, FSM says 135mm or 5.31". But I have seen many mag reports (getting their info from Yamaha) say 137.2mm or 5.4". Yamaha website says 5.3" so I will go with that number.
For rear, FSM doesn't say. Most mag reports say 121.9mm or 4.8". But I have seen one that says 125mm or 4.9". And Yammie website says 4.9". So which is it? I know, not a big deal. Just would like the correct number to base my SAG calculations on.
I assume the spring rate info is correct, but how about suspension travel?
For the front, FSM says 135mm or 5.31". But I have seen many mag reports (getting their info from Yamaha) say 137.2mm or 5.4". Yamaha website says 5.3" so I will go with that number.
For rear, FSM doesn't say. Most mag reports say 121.9mm or 4.8". But I have seen one that says 125mm or 4.9". And Yammie website says 4.9". So which is it? I know, not a big deal. Just would like the correct number to base my SAG calculations on.
+1 - I agree 100% there.
Excellent point, Greg. The FSM shows the shock stroke specs, but you'd need to know all of the angles and dangles to figure out what the amplification factor is for one mm in shock stroke as it relates to the rear wheel travel. That info isn't shown anywhere, but that is what we need to deal with for setting up the suspension.
Chiefblueman
Well-known member
I'm curious, what makes you say the Gen1 springs are NOT dual rate? I just pulled my stock Gen1 springs out of storage and they appear to be dual rate to me. The upper third of the spring has coil spacing of approximately .200 in. and the coils are smaller in diameter while the remainder of the spring has coil spacing of .400 in. Both coil diameter and coil count affect spring rate. There is a transition between the two "rates" to avoid a sharp bend in the wire but it is definitely not a straight wound single rate spring.
I have never seen a Gen2 spring in person and cannot comment on it, but the single rate of .85 would hold the fork higher in its stroke than the initial .80 of the Gen1 (not by much) and be less harsh at mid stroke than the .99 secondary of the Gen1. This was my observation of my gen1 fork prior to changing springs, at full preload it still sagged to much and was not very compliant, kind of wooden feeling. Damping is important but it can't fix an inappropriate spring.
MCRIDER007
Well-known member
This is a picture of the 05 fork springs and the Wilber's FJR springs.
The Wilber's springs (the longer springs) are clearly dual rate and when compressed the tightly wound springs on the left will bind fairly quickly, reducing the number of coils and increasing the spring rate for the remainder of the compression.
After taking a lot of measurements, it does appear that the FJR springs ARE dual rate because 6 coils (5 on the left, 1 on the right) will bind after the spring compresses about 4 inches. This is pretty close to the spring's limit of compression because the actual travel (when measured with no springs installed) is less than advertised and the oil lock takes away another 20-25 mm of travel to prevent metal to metal bottoming. I stated earlier that the FJR springs appeared to be slightly progressive rather than dual rate but after partially compressing them by hand and measuring the gap between the coils I think there are actually 3 rates, 2 of the coils (top and bottom coils) will bind after about 60mm of compression and the other 4 coils will bind about 40mm later. For all practical purposes, the spring will be in the lower or middle rate almost all the time during normal riding and the highest rate will kick in at the very end of the stroke under heavy braking....which is a more useful use of dual rate springs than the Wilbers which has tighter coils and will blow through the soft rate just from the weight of the bike and rider.
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Chiefblueman
Well-known member
I follow your logic. However, the installed length of the spring is 1.2 in shorter than the spring free length indicating it is installed with preload (it is). At about 4.8 in (3.58+1.2) of spring compression, not fork travel, the closer wound coils should bind. Rigging up a crude spring compressor using two different sizes of pipe, a couple big washers and a vice I can bind the first 6 coils in about 5 inches using my fat ass as the compressing force. Not exactly scientific, but the spring does exhibit dual rates.
MCRIDER007
Well-known member
I have been editing my post since you posted so you should re-read everything I changed. As far as installed preload, it hard to determine how much the spring is actually compressed because of the top out springs. When you push down on the main spring you are also lifting the bottom of the fork tube against the top out spring and the actual preload on the main spring is going to be dependent on the relative resistance of the 2 springs. If it took you 5 inches of spring compression to bind the first 6 coils then I think that coil binding is only going to happen in the real world under heavy braking .
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I think you should be able to estimate the actual preload by the difference between the free and installed lengths in the specs. I would imagine that they have taken the top-out springs into consideration with the installed length. The spec is probably with the pre-load adjuster in the "nominal" middle position.
The pre-load adjuster doesn't give you a 1:1 change in pre-load, I've proven that to myself by adjusting and re-measuring sag. But it also isn't only compressing the top-out springs. The main spring must also deflect some percentage of the change in the adjuster height. You could calculate the actual ratio based on the two spring strengths (top-out and main) if we knew the top-out spring weight. [edit - Oops, looks like I just re-iterated what MCRider just said. That's what I get for responding before reading the full post
]
PS - Looking at the picture, it does look like maybe the two ends of the stock 1st gen spring could make up the softer 91mm "K1" part of the spring. My straight weight sonic is perfectly even spaced, and the same diameter coils, all the length of it.
The pre-load adjuster doesn't give you a 1:1 change in pre-load, I've proven that to myself by adjusting and re-measuring sag. But it also isn't only compressing the top-out springs. The main spring must also deflect some percentage of the change in the adjuster height. You could calculate the actual ratio based on the two spring strengths (top-out and main) if we knew the top-out spring weight. [edit - Oops, looks like I just re-iterated what MCRider just said. That's what I get for responding before reading the full post
PS - Looking at the picture, it does look like maybe the two ends of the stock 1st gen spring could make up the softer 91mm "K1" part of the spring. My straight weight sonic is perfectly even spaced, and the same diameter coils, all the length of it.
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