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Edit: This thread contains both good and bad info that I left fairly intact for the purpose of illustrating how misinformation can lead one to erroneous conclusions. Good intentions were there and a lot of work was done. This thread was a learning experience for all involved. TIFWIW -- Currently

Suspension is not black magic if you know what you are looking for...​


Here are the STOCK fork spring rates:
  • 1999 - 2001 SV650 have 0.706 kg/mm fork springs.​
  • 1999 - 2001 SV650S have 0.706 kg/mm fork springs.​
  • 2002 SV650 have 0.712 kg/mm fork springs.​
  • 2002 SV650S have 0.706 kg/mm fork springs.​
  • 2003 - 2008 SV650 have 0.712 kg/mm fork springs.​
  • 2003 - 2008 SV650S have 0.670 kg/mm fork springs.​
These are the fork spring rates at www.racetech.com ...Follow the link to "Sport Bike" and look for "Spring Rate Search"

Recommended 1ST Generation SV650 and SV650S Fork Spring Rates.
  • 105 - 130 lbs Rider - 0.75 kg/mm spring.​
  • 130 - 160 lbs Rider - 0.80 kg/mm spring.​
  • 160 - 195 lbs Rider - 0.85 kg/mm spring.​
  • 195 - 230 lbs Rider - 0.90 kg/mm spring.​
  • 230 - 260 lbs Rider - 0.95 kg/mm spring.​
  • 260 - 350+ lbs Rider - 1.00 kg/mm spring.​
Recommended 2ND Generation SV650 and SV650S Fork Spring Rates.
  • 90 - 125 lbs Rider - 0.80 kg/mm spring.​
  • 125 - 155 lbs Rider - 0.85 kg/mm spring.​
  • 155 - 190 lbs Rider - 0.90 kg/mm spring.​
  • 190 - 225 lbs Rider - 0.95 kg/mm spring.​
  • 225 - 350+ lbs Rider - 1.0 kg/mm spring.​
Here are the STOCK shock spring rates:

  • 1999 - 2002 SV650 and SV650S have 510 lbs/inch - 9.129 kg/mm shock spring.
  • 2003 - 2008 SV650 and SV650S have 430 lbs/inch - 7.697 kg/mm shock spring.​

These are the shock spring rates at www.penskeshocks.com ...Follow the link to "Motorcycles" and look for "Spring Chart"


Recommended 1ST Generation SV650 and SV650S Shock Spring Rates.
  • 120 - 160 lbs Rider - 625 lbs/inch - 11.19 kg/mm spring.​
  • 160 - 190 lbs Rider - 650 lbs/inch - 11.64 kg/mm spring.​
  • 190 - 225 lbs Rider - 675 lbs/inch - 12.08 kg/mm spring.​
  • 225 - 260 lbs Rider - 700 lbs/inch - 12.53 kg/mm spring.​
Recommended 2ND Generation SV650 and SV650S Shock Spring Rates.
  • 120 - 160 lbs Rider - 475 lbs/inch - 8.50 kg/mm spring.​
  • 160 - 190 lbs Rider - 500 lbs/inch - 8.95 kg/mm spring.​
  • 190 - 225 lbs Rider - 525 lbs/inch - 9.40 kg/mm spring.​
  • 225 - 260 lbs Rider - 550 lbs/inch - 9.85 kg/mm spring.​
To covert to kg/mm multiply lbs/inch * 0.0179 IE. 500 lbs/inch * 0.0179 = 8.95 kg/mm
To covert to lbs/inch divide kg/mm / 0.0179 IE. 8.95 kg/mm / 0.0179 = 500 lbs/inch​

Hope this helps you figure out your suspension set up.​

Luis


PS: If these seem different of something you have seen before, please post a link and reference to back up your findings.​
 

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Re: Spring Rates for the SV650

Those Race-Tech tables don't make much sense. The first gen and second gen SVs are virtually the identical weight, so why the different rate recommendations for riders of the same weight?? Might have made more sense if they'd split it up by "S" vs. non-"S", since the riding position with the "S" puts a bit more weight on the front end.

The Penske chart is ok for racing, a bit stiff for street use.
 

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Re: Spring Rates for the SV650

I'm puzzled by that too. In the spring of '04 I bought emulators and springs for my nekkid '03 SV650 from Race-Tech and spoke to one of their techs. He recommended .80 kg./mm. springs for my 150 lb. rider weight. IMO it was the right call.
 

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Re: Spring Rates for the SV650

Actually both the naked and the S should have the same spring rates unless you are leaning too heavily on the bars with the S model. With the lower bars you should still have the bulk of your weight on the seat and the pegs. The purpose of lower bars is aerodynamic.

Given the weight distribution I don't understand why different generations would call for different spring rates.
 

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Re: Spring Rates for the SV650

The front fork springs are wrong. Unlike the rear, there is no difference in "mechanical advantage" for the front on either Gen's.

Look at Sonic Spring's website. The springs are the same for both Gen's. The rate calculator is more accurate than Racetech's. Bike weight, rider weight, and rider style that's it. It does not matter what bike.
 

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Discussion Starter · #6 ·
Re: Spring Rates for the SV650

If you go to www.racetech.com there is a difference on the spring rate recommendations from 99-01 from 02 and from 03-08. I am not the expert. I am just gathering the information for those who care to use it.

And if you think these are off post a link to where you think the information is more accurate. I will search for Sonic Spring website... Luis
 

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Re: Spring Rates for the SV650

ohlins suggestions, rear shock:

01096-21: Fits "dressed" rider weight of 155-175#. 428lbs
01096-24: one step up. Fits dressed rider weight of 175-200#. 457lbs
01096-26: two steps up. Fits dressed rider weight of 200-225#." 485lbs

ohlins suggestions, fork springs

0.80kg/mm standard
0.85kg/mm heavy and/or aggressive rider



i measured 2 pairs of springs coming from european 2nd generation naked k3:
they all were 0.60kg/mm


tech italian magazine "mototecnica" measured 1st generation at 0.60kg/mm too

faired 2nd generation have dual stage springs. firts part of the travel is 0.60kg/mm then it becomes harder. i was not able to fully compress the spring but my average was 0.67kg/mm

imho racetech's datas about naked versione are wrong , at least for bikes selled in Italy.
well known italian magazine "Motociclimo" wrote that naked k3 was not as supportive as faired k3. this opinion matches my datas.
 

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Discussion Starter · #8 ·
Re: Spring Rates for the SV650

i look at the race tech chart and think it's self serving according to that chart a 105 lb person still needs to buy springs from them, that's kind of funny, i weigh maybe 170 in full gear and i consider the fork springs marginal for street. I have ordered tires (ct2s) and a Traxxion drop in kit and i have front brake upgrade stuff ready to go on with the fork upgrade.I'm sticking with the stock springs for now i consider them pretty stiff, but maybe proper dampening, that release valve working on choppy bumps my fork may actually become to soft with the drop in emmulator kit,but i need to experience that first hand.
Do you seriously think racetech is in business to take a customer for a set of springs it does not need? ....I do not think so.

The reason they recommend stiffer fork springs is because stock forks are ancient technology and the stock fork springs are way, way, way too soft. It is easy to verify this. Go 25 mph and brake somewhat fast. You should not be able to bottom out your forks under braking. Not even under maximum braking power. On the SV the forks bottom out if you brake 1/4 of the front brake potential.

It's great that you are taking steps toward performance... And my advise to you is to listen to the pros. if they suggest your springs are good to go. keep them!!!

According to www.racetech.com your 2002 SV650 has 0.706 kg/mm stock fork springs. They are set up for an 85 lbs rider. Yes, 85 pounds!!! ....If you are 170 lbs with gear, you are probably 150 lbs. At 150 you should use 0.85 kg/mm.

Do not expect to fix your spring rate with dampening... That does not work!!! The dampening, compression or rebound are not going to affect your spring rates in anyway. It only affects the movement of the spring. If you are trying to compensate a soft spring with more compression dampening... What are you doing?

  • A.- You are overworking the emulators or the valving and heating the fork fluid.
The first step to set up your suspension is to have the proper springs for your weight. It is the only way to set up proper sag. If you have proper spring, static and rider sag will require minimal preload adjustment. Without compromising dampening, compression or rebound.

I am not saying do as I say.... Call Traxxion Dynamics and ask them for performance set up for you and your bike. They know their stuff... If they tell you that your springs are fine, keep them. I have a hunch they are a little soft.
 

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Re: Spring Rates for the SV650

Spring technology is pretty much static and has been for a long time. The biggest advances in motorcycle springs came when manufacturers went to alloys that don't fatigue and sag over time.

Too stiff a spring is as big a mistake as too soft a spring. Too stiff a spring will preclude adequate preload and so lead to topping out. Too soft a spring will lead to too much preload and not enough compression stiffness.

A good spring is one that allows setting preload so that the suspension is roughly 30% compressed at total sag at the correct ride height. You can run stiffer springs on some race tracks because there aren't as many dips to contend with. Some race tracks are not table smooth, so spring selection tends more to street-type stiffnesses.
 

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Re: Spring Rates for the SV650

Can you believe suzuki is setting up the sv for an 85 lb rider? they must be really dumb,what kind of marketing/engineering is that. The Sv must be their first attempt,maybe they'll learn when they get a little experience. Racetech isn't trying to rip anybody off either, they just have different standards and their chart represents those standards,there's race in the name racetech.I'm not racing ,i've been meaning to see how much travel i do use on with the ol zip tie method, i'll check on the dive thing. i do think it's ok to use the compression dampening to reduce dive,that's not gonna overheat the fluid. I'm gonna stick with my idea of making one change at a time to the suspension in fact i'm actually doing two things i've heard that for normal street use just going to thicker fluid is good enough.The springs feel stiff enough to me,i'm getting the drop in cartage emmulators to go with the heavier fluid so that on the slow speed valving thay should reduce dive ,but the blowby high speed valve should keep it from being harsh over patches and seams at highway speed. I'm not trying to cut seconds off my lap times. By the way when i get on my sv i don't think there's a whole lot of sag,i am gonna check that tonight,it's ccccold and i wasn't planning any rides for a couple of days.
 

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Discussion Starter · #12 ·
Re: Spring Rates for the SV650

Can you believe suzuki is setting up the sv for an 85 lb rider? they must be really dumb,what kind of marketing/engineering is that. The Sv must be their first attempt,maybe they'll learn when they get a little experience. Racetech isn't trying to rip anybody off either, they just have different standards and their chart represents those standards,there's race in the name racetech.I'm not racing ,i've been meaning to see how much travel i do use on with the ol zip tie method, i'll check on the dive thing. i do think it's ok to use the compression dampening to reduce dive,that's not gonna overheat the fluid. I'm gonna stick with my idea of making one change at a time to the suspension in fact i'm actually doing two things i've head that for normal street use just going to thicker fluid is good enough.The springs feel stiff enough to me,i'm getting the drop in cartage emmulators to go with the heavier fluid so that on the slow speed valving thay should reduce dive ,but the blowby high speed valve should keep it from being harsh over patches and seams at highway speed. I'm not trying to cut seconds off my lap times. By the way when i get on my sv i don't think there's a whole lot of sag,i am gonna check that tonight,it's ccccold and i wasn't planning any rides for a couple of days.


LOL ...If you do not want performance why are you bothering with suspension components?



First, I don't think Suzuki engineer the SV650S to be a super sport race bike like the GSXRs.

Second, racetech is just company, like any other suspension company out there. They provide products to those who demand ultimate performance. Like for serious canyon riders or for racing applications.

I think you are not understanding the theory of suspension. We do not want to ride a caddy, Suspension is all about keeping the tires in contact with the ground. keeping the chassis settle over road irregularities, supporting cornering centrifugal forces. and braking forces. To a leaser extent keep the rider somewhat comfortable.

You are right on the money, with the idea of changing only one thing at a time. That is great advise for fine tuning. You know... Once you have all the right components.

Think of it this way, Springs provide support. they should sag about 1/3 at rest. to provide with 1/3 travel down into a hole on the road. Compression controls the speed of up-wards movement of the wheels when then come up to a bump on the road. Rebound controls the speed of down-wards movement of the wheels when they passed the bump...

You adjust the compression dampening just enough so the tire does not lose contact at the top of the bump. You adjust rebound dampening just enough brings the tire back down over the bump.

If you crank up compression dampening, the compression stroke of the spring will not be able to travel far enough to ride over the bump. First you are going to feel a harsh ride because the spring is not allowed to absorb the impact. then the worst is that the tire will bounce off the road... If you are in a corner you are now going wide.

Remember dampening is only under movement. if there is no pressure you are just sitting on your saggy springs.

You can not use ticker oil on the emulators unless you re-stack the shims to work with ticker fluid. you actually want the recommended (thinner) fluid to make the valving work smoothly.

Check your sag. you will need a helper and a metric tape.

Set your without rider first. You must be able to hit with rider mark without readjusting it.

Without rider (static sag):
Rear: 10-20 mm
Front: 15-30 mm

With rider (ride height):
Rear: 25-40 mm
Front: 35-50 mm

My bike is at 15/30 on the rear 20/40 on the front.

Look, I am not picking on you.... I just would like you to know what's up. A year ago I did not know... It was supposed to be "BLACK MAGIC"!!! Then I read a few books about suspension theory, Suspension settings, Talked suspension with racers, and discussed things with suspension specialist. Latter decided to take suspension clinics classes.
I know the local distributors of Race-Tech and Ohlins.

Take the advise as a reference point or leave it... Luis
 
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Discussion Starter · #13 ·
Re: Spring Rates for the SV650

See if figures help ya!!!






Luis​
 

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Re: Spring Rates for the SV650

Those Race-Tech tables don't make much sense. The first gen and second gen SVs are virtually the identical weight, so why the different rate recommendations for riders of the same weight?? Might have made more sense if they'd split it up by "S" vs. non-"S", since the riding position with the "S" puts a bit more weight on the front end.

The Penske chart is ok for racing, a bit stiff for street use.
keep in mind that they are both different chassis and the rear suspension geometry is not alike.

The 2nd gen s and n models also have different length swingarm.
 

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Re: Spring Rates for the SV650

Many people make the mistake that "racing" springs have to be "stiffer". That's not the generally the case. The stiffer the spring the harder it is to get damping right for larger suspension excursions (bumps, dips, braking, cornering, etc.). The "correct" spring is the one that gives the optimum available suspension travel for the bike and rider combined.

Running a stiffer spring than you need reduces preload at the optimum ride height making the suspension more likely to top out and requiring harder rebound damping. This combination can lead to "pump down".

Running a softer spring than you need increases the preload at optimum ride height, which isn't in itself bad at all. The problem becomes that compression damping has to be harder to prevent excessive travel over bumps. This usually feels harsh.

So, again, shoot for 5% to 10% static sag, 30% total sag. With that combination adjust compression and rebound damping accordingly.

I'll qualify all that by saying if you're a serious racer then you will probably make small changes for each particular track. For street riders the procedure above makes for a rideable bike over the variety of public roads and weather conditions most street riders will experience.
 

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Re: Spring Rates for the SV650

Ok, inspirational, i just put my SV up on the stand (dyi) that lifts it from the frame sliders(dyi) and the fork length is 130,With the bikes weight it sags to 105 then with my punny self on it it went to 92, didn't need a helper i put a zip tie around the fork leg. a third of the travel would be 43.3mm i have 38. stock(i think) 2002 sv naked i bought last year with 114 miles from two weeks of use , unless the previous owner had the springs changed straight out of the showroom,he didn't mention it,the total sag is about right.In fact,i didn't put on all my gear for this, add 15 lbs and it might even be exactly to your sag spec. I left the zip tie on, at some point i gotta check that brake induced dive thing,i'm sticking with my feelings that a low speed dampening circuit is the best way to stop brake induced suspension dive and it makes even more sense with thinner suspension fluid. I'll probabely use what ever Traxxion reccomends.
 

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Re: Spring Rates for the SV650

Actually both the naked and the S should have the same spring rates unless you are leaning too heavily on the bars with the S model. With the lower bars you should still have the bulk of your weight on the seat and the pegs. The purpose of lower bars is aerodynamic.

Given the weight distribution I don't understand why different generations would call for different spring rates.
Different Shock linkage leverages.....(between 1st and 2nd gen) 1st gen requires a stiffer spring overall for the same rider weight due to more leverage on the shock....
 

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Discussion Starter · #19 ·
Re: Spring Rates for the SV650

Are there markings on the stock springs? And how are Race Tech Springs marked?
No markings on stock forks....

Aftermarket forks are individually measured and then are matched in pairs. The acctual Spring rate number is etched on one of the ends of the springs

Luis





keep in mind that they are both different chassis and the rear suspension geometry is not alike.

The 2nd gen s and n models also have different length swingarm.

Do they do not!!!

They have different gear ratios and thats why the SV650 has a longer chain than the SV650S.

Swing arm is the same lenght
 

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Re: Spring Rates for the SV650

No markings on stock forks....

Aftermarket forks are individually measured and then are matched in pairs. The acctual Spring rate number is etched on one of the ends of the springs

Luis








Do they do not!!!

They have different gear ratios and thats why the SV650 has a longer chain than the SV650S.

Swing arm is the same lenght
N wheelbase 56.7" 1440 mm
S wheelbase 56.3" 1430 mm
 
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