Suspension Adjustment

[porky45]

bump it up to 5 and you'll notice a difference in response and handling if you've been muckin' it in 2.

 

[Superfly]

bump it up to 5 and you'll notice a difference in response and handling if you've been muckin' it in 2.

I dont think you watched the video...it really just depends on how much the rider weighs...i wouldnt have very much sag or maybe none at all set at 5. Thats not the best way to set up a bike.

 

[Grinch79]

Is the only way to reduce that sag when I add a passenger is to change the rear spring and set up all together? Would adding a thicker weight help me go from a 7 now to a 5 where then with my passenger I could bump it up to a 7 at that point without feeling the sag back there?

I know I've seen some prices thrown around but what is an average price on a rear suspension swap? Next I guess is do we need to change both the front and rear when we mess with the suspension?

 

[JSP]

Is the only way to reduce that sag when I add a passenger is to change the rear spring and set up all together? Would adding a thicker weight help me go from a 7 now to a 5 where then with my passenger I could bump it up to a 7 at that point without feeling the sag back there?

I know I've seen some prices thrown around but what is an average price on a rear suspension swap? Next I guess is do we need to change both the front and rear when we mess with the suspension?

You can change just the rear spring to get you more play in the preload. I have the HyperPro rear spring (stock shock) and its WAY more stiff. Im on 4 right now and I am about 220 geared up. I didnt even move it with my wife on the back. We just took about a 50 mile ride and the bike handled awesome. I may bump it up to 5 just to see how it handles.

I dont think you need to do the front if all you are looking for is a stiffer rear. You could surely benefit from the front if you so chose to though.
Or you could just swap the fork oil with a heavier oil. Stock is 5wt I think. I am running 15wt oil with HyperPro springs in the front.

 

[Grinch79]

Do you have a link where you bought it for cost and color?

 

[JSP]

Do you have a link where you bought it for cost and color?

I got mine from EPM Performance. You can email Dee at [email protected]

She is very helpful and very quick to return emails.

You can get a purple or black spring. I went with the black.

I got the combo kit which came with the front springs and fork oil and rear spring for $280 shipped.

YAMAHA XJ-6/ FZ-6R 08>
SP-YA06-SSA040 $139.00 Front springs
SP-YA06-SSB040 $126.00 Rear Spring
SP-YA06-SSC040 $259.00 Combo

 

[frankvip20]

i had a question i want to lower my bike from the front end... how can i do this...and if i do it do i have to lower the back because i actually want to raise the back a bit...thanks

 

[Spunky99]

I went with Racetech.

Product Search

The 2009 and 2010 are the same suspension and interchangeable if you go look up the application guide.

Here is info on the sag
http://www.racetech.com/html_files/preload.htm

109.99 front springs
119.99 rear spring
40.00 15w fork oil

They are in Corona CA so I did a local pickup.
I had the local Yamaha shop swap the rear spring and I did the front myself.
You need a hoist or some way to hold the front of the bike up when loosening the triple clamps....

My bike is stiff the way I set it up like a track bike on the street. I love it and am actually chasing Elephants now.

 

[nlpyle]

Spunky awesome link, now here is my problem, I can't figure out how to read that list to choose from. What are all the different numbers mean

FRSP S3534080 RT FRK SPR 34.7x340mm .80kg $109.99
FRSP S3534085 RT FRK SPR 34.7x340mm .85kg $109.99
FRSP S3534090 RT FRK SPR 34.7x340mm .90kg $109.99
FRSP S3534095 RT FRK SPR 34.7x340mm .95kg $109.99
FRSP S3534100 RT FRK SPR 34.7x340mm 1.0kg $109.9

REAR SHOCK SPRING
Recommended Rear Shock Spring Rate for Street: 20.44 kg/mm (use closest available)
Stock Shock Spring Rate: 17.6 kg/mm (stock)
Available SESP 70225 Series Springs are:


Part Number Description Price Select to Buy
SESP 702250250 SK SPRING 7.0 x 2.25" 4.5kg $119.99
SESP 702250300 SK SPRING 7.0 x 2.25" 5.4kg $119.99
SESP 702250325 SK SPRING 7.0 x 2.25" 5.8kg $119.99
SESP 702250350 SK SPRING 7.0 x 2.25" 6.3kg $119.99
SESP 702250375 SK SPRING 7.0 x 2.25" 6.7kg $119.99
SESP 702250400 SK SPRING 7.0 x 2.25" 7.1kg $119.99
SESP 702250425 SK SPRING 7.0 x 2.25" 7.6kg $119.99
SESP 702250450 SK SPR 7x2.25" 8.0kg (use RT) $119.99
SESP 702250475 SK SPR 7x2.25" 8.5kg (use RT) $119.99
SESP 702250500 SK SPR 7x2.25" 8.9kg (use RT) $119.99
SESP 702250525 SK SPR 7x2.25" 9.4kg (use RT) $119.99
SESP 702250550 SK SPR 7x2.25" 9.8kg (use RT) $119.99
SESP 702250600 SK SPR 7x2.25" 10.7kg (use RT) $119.99
SESP 702250650 SK SPR 7x2.25" 11.6kg (use RT) $119.99
SESP 702250700 SK SPRING 7.0 x 2.25" 12.5kg $119.99
SESP 702250750 SK SPRING 7.0 x 2.25" 13.4kg $119.99
SESP 702250775 SK SPRING 7.0 x 2.25" 13.8kg $119.99
SESP 702250800 SK SPRING 7.0 x 2.25" 14.3kg $119.99
SESP 702250850 SK SPRING 7.0 x 2.25" 15.2kg $119.99
SESP 702250900 SK SPRING 7.0 x 2.25" 16.1kg $119.99
SESP 702250950 SK SPRING 7.0 x 2.25" 17.0kg $119.99
SESP 702251000 SK SPRING 7.0 x 2.25" 17.8 kg $119.99
SESP 702251100 SK SPRING 7.0 x 2.25" 19.6kg $119.99
SESP 702251200 SK SPRING 7.0 x 2.25" 21.4kg $119.99
SESP 702251300 SK SPRING 7.0 x 2.25" 23.2kg $119.99
SESP 702251400 SK SPRING 7.0 x 2.25" 25.0kg $119.99

Yes I am simple and don't always understand mech. language but working on it. So just curious as to how someone chooses which one they would need.
But seriously a really cool tool. Asks you the how much you weight with gear and then recommends the parts for you.

 

[JonKerr]

I went with Racetech.

Product Search

The 2009 and 2010 are the same suspension and interchangeable if you go look up the application guide.

Here is info on the sag
http://www.racetech.com/html_files/preload.htm

109.99 front springs
119.99 rear spring
40.00 15w fork oil

They are in Corona CA so I did a local pickup.
I had the local Yamaha shop swap the rear spring and I did the front myself.
You need a hoist or some way to hold the front of the bike up when loosening the triple clamps....

My bike is stiff the way I set it up like a track bike on the street. I love it and am actually chasing Elephants now.

When you did this, how did you drain the fork oil? Did you completely remove the fork tube and pour it out or did you siphon it out somehow?

 

[JSP]

When you did this, how did you drain the fork oil? Did you completely remove the fork tube and pour it out or did you siphon it out somehow?

The problem with siphoning is that you wont get it all out and it will leave lots of "gunk and crud" deposits that sank to the bottom in there. Best way is to take the forts out and compress them multiple times to get all of it out.

 

[Spunky99]

I attached a 1 ton hoist to the roof of my garage and strapped under the front of the frame behind the triple tree. I put a rear stand to stabilize the bike and lifted the front end off the ground and removed the tubes and pumped them real good and let them sit draining for almost an hour while I took a break.
Then pumped again..open and close, open and close the tubes. collapse and extend....the oil has a silverish look from the aluminum powder during breakin.....good to get fresh oil as the seals will last longer.

I did have a bitch of a time putting in the spacers because I made mine extra long so my sag is like 20mm front and rear. It handles like a track bike..I kidd you not! I had to push the fork caps down really hard to compress the springs and get the threads to start without cross threading. It took all my strength and weight for almost an hour to get the caps on. But normally the spacers don't need to be that long as a 30 to 40mm sag is normal...even for track use...I prefer stiffer.....If I wanted a cruiser, I'd have bought one..right!

When looking at the tables, leave the bike at 470 pounds and add your weight fully dressed. Example...I weigh 220 with helmet and gear so I add 220.
Click on the red calculation line on the page, there are 3 of the lines in red and they are all the same. It takes you to the calculator.
Here...
Spring Rate Calculation

Then put your weight in the first box and select calculate spring weight now.
On the next page near the top you see the calculation.
Rider Weight: 220 lbs.
Bike Weight: 460 lbs.

FRONT FORK SPRINGS
Recommended Fork Spring Rate: 0.988 kg/mm (use closest available)
Stock Fork Spring Rate: .900 kg/mm (stock)
Available FRSP S3534 Series Springs are:

I went for the last one in the first table for front fork springs because it was closest to .988kg
FRSP S3534100 RT FRK SPR 34.7x340mm 1.0kg

Scroll down and find the calculation for the rear spring.
REAR SHOCK SPRING
Recommended Rear Shock Spring Rate for Street: 19.75 kg/mm (use closest available)
Stock Shock Spring Rate: 17.6 kg/mm (stock)
Available SESP 70225 Series Springs are:

I went for the 19.6 being the closest and I'm losing weight anyway and the 21.4kg is too stiff and is better suited to a 320 lb + rider.
SESP 702251100 SK SPRING 7.0 x 2.25" 19.6kg

So front fork springs are FRSP S3534100
and rear shock spring is SESP 702251100

You don't have to but I bought the $40.00 quart of their 15w oil so I didn't have to go find it online as the numbers were hard to figure out to get the right weight. Use 1/2 qt in each fork tube and you are done.
The front springs come with the aluminum spacers that you cut custom and instructions to estimate the sag so you cut them the right length for the sag you want.

Make sure you have a Yamaha or another bike shop do the rear shock spring swap...Unless you have an extra heavy duty spring compressor with the right size fittings, there is no way in Hell you are gonna do it yourself. Cost me $20.00 and took the guy almost an hour....enuf said....

I dropped my fork tubes so they stick up almost 1.5mm above the top tree to get it to turn into the corners easier and I can come into a corner way too fast and hit the brakes really hard without front end dive which forces you wide. So I can keep a tight line into the beginning of the turn and have fun while in the turn as the rear end is stable and smooth as a baby's butt. Now that I have the Metzler Sportec M5 Interact tires scratched in, they are sticky and I feel no fear of slipping in the turns with the bike so stable. I look where I am going to go and the bike goes there without complaint.

Now hitting bumps on the freeway, the rear shock likes to buck a bit so you gotta watch that..but then I have the preload at 5 on the rear for a 20mm sag too.....nutz..yeah

 

[JonKerr]

I'm really getting close to being able to do this. I'm checking with my mechanic who does my tires to see what he'll charge me to do the work since I don't have the equipment to do it the right way. Now I'm seriously looking into the emulators that they have. That's in addition to the custom springs and oil correct? Or am I missing something again?

Also, does the rear shock have any kind of bouncy feeling with that heavy spring and no additional dampening? No pogo stick effect?

 

[Marthy]

By changing preload, you're essentially using a stiffer section of the spring. All springs are progressive, i.e. the further you compress them the harder it gets to compress. So by adding preload you're in effect using the portion of the spring that's harder to compress, essentially changing the spring rate. The problem with just doing spring rate and not dampening (the oil and pistons inside the shock) is you can get kind of a bouncy springy feeling. Dampening slows down, not only the compression of the shock, but the rebound. Many bikes have these two as separate adjustments. If you're too heavy for the stock spring in the stock location, there isn't enough spring rate there to hold the ride height of the bike up. This causes you to ride lower as the spring is compressing to the portion of the spring that will hold you up by moving the suspension. This lowers your ride height and make you ride at the top of the stroke which can cause it to bottom out. By adding preload, you're loading the spring to the rate you need to hold your weight up before the suspension moves at all.

If you're 200# with gear, you should be at 5 or 6 at minimum. I'm in the 230 range in gear and I ride at 6 and sometimes 7.

You are right that some springs are progressive, but most of all springs are linear. It doesn't mater how much preload you put on a 500 lbs/in spring, it still going to be a 500 lbs/in spring. Meaning you need 500 lbs to make the spring move 1 inch. By adding some preload on a spring all you change is the amount of load required to INITIALLY move the spring.

By example: In position 1, let say that you need 50 lbs to make your bike starting to "sag"
Position 2 might get it up to 75 lbs...

I don't have any exact number of how much 1 click worth on our bike, but I'm sure you're getting the idea. The video on this thread is really good to set the sag. But since we don't have "real shocks" with real adjustment, preload is the only way to kind of tune the bike.

So just like on race cars.

 

[JonKerr]

You are right that some springs are progressive, but most of all springs are linear. It doesn't mater how much preload you put on a 500 lbs/in spring, it still going to be a 500 lbs/in spring. Meaning you need 500 lbs to make the spring move 1 inch. By adding some preload on a spring all you change is the amount of load required to INITIALLY move the spring.

By example: In position 1, let say that you need 50 lbs to make your bike starting to "sag"
Position 2 might get it up to 75 lbs...

I don't have any exact number of how much 1 click worth on our bike, but I'm sure you're getting the idea. The video on this thread is really good to set the sag. But since we don't have "real shocks" with real adjustment, preload is the only way to kind of tune the bike.

So just like on race cars.

Yes springs are rated as the load required to move it 1". But the more you compress it, the harder it is to compress. That's called progressive rate and that is true with ALL compression springs. Some springs that are sold as progressive springs are much more progressive. But even springs that are "linear" are still progressive by nature. I've watched race car springs get rated. They're linear springs but the further that spring dyno compressed, the pressure required goes up exponentially. How much of an exponential increase is what determines how progressive a spring is. By adding preload, you're getting the spring preloaded to a certain compression amount, increasing the force required to compress it another 1".

 

[Marthy]

Yes springs are rated as the load required to move it 1". But the more you compress it, the harder it is to compress. That's called progressive rate and that is true with ALL compression springs. Some springs that are sold as progressive springs are much more progressive. But even springs that are "linear" are still progressive by nature. I've watched race car springs get rated. They're linear springs but the further that spring dyno compressed, the pressure required goes up exponentially. How much of an exponential increase is what determines how progressive a spring is. By adding preload, you're getting the spring preloaded to a certain compression amount, increasing the force required to compress it another 1".

Maybe your right, I'm not here to try to convince you. All I have to say is, in Formula Atlantic by example, we were caring springs from 350 lbs/in to 1400 lbs/in by 25 lbs increments, 4 springs of each... do the math! I won't get into our inventory of bump stop and packers. All i'm saying here is cranking some preload is not increasing spring rate, it's just changing the characteristic of the initial movement of the spring. I agree with you that if you compress the spring 1/2" and compress it another 1" it will go up more than what the spring is rated for, but it's not the same.

Thrust me, if everybody in motorsports could get away with only 1 set of spring and just play with preload, everybody will do it. $$$$ talk!

Cheers!

 

[Spunky99]

I'm really getting close to being able to do this. I'm checking with my mechanic who does my tires to see what he'll charge me to do the work since I don't have the equipment to do it the right way. Now I'm seriously looking into the emulators that they have. That's in addition to the custom springs and oil correct? Or am I missing something again?

Also, does the rear shock have any kind of bouncy feeling with that heavy spring and no additional dampening? No pogo stick effect?

By changing the rear spring to one that is rated for my weight, I actually removed the pogo effect that the stock spring was giving me. The dampening did not change but it seems adequate for the heavier spring in this application.
I only adjusted the preload to set the sag to 20mm.

 

[JonKerr]

Maybe your right, I'm not here to try to convince you. All I have to say is, in Formula Atlantic by example, we were caring springs from 350 lbs/in to 1400 lbs/in by 25 lbs increments, 4 springs of each... do the math! I won't get into our inventory of bump stop and packers. All i'm saying here is cranking some preload is not increasing spring rate, it's just changing the characteristic of the initial movement of the spring. I agree with you that if you compress the spring 1/2" and compress it another 1" it will go up more than what the spring is rated for, but it's not the same.

Thrust me, if everybody in motorsports could get away with only 1 set of spring and just play with preload, everybody will do it. $$$$ talk!

Cheers!

I think what's confusing is that I said it "essentially" changes the spring rate. I used that term so those who don't really have experience with this stuff get the idea. No, your spring rate will not change with preload. But you're using an area of the spring that requires more pressure to compress. I worked on a pit crew for my cousin racing IMCA Modifieds, Super Late Models, and Southwest Tour. So I know about needing an expensive inventory of springs. Also I was a sponsored RC Car racer and kept a spring inventory of about 40 sets of springs of various rates, different progressions, etc...

 

[Superfly]

After playing around for a month with my 999's suspension and watching dave moss and a couple other internet gurus I think the issue with the FZ6R is front rebound damping. When I hold the front brake and push the forks down hard they spring up too fast and then come back over the top and start down again...then back up to a rest. This shouldnt happen. Your rebound should come up to about the starting point but not go over the top to start another stroke.

This is probably the biggest issue with the FZ6R. And the cause of the wallowing feeling during cornering. I think the compression in the front is OK for me being around 170lbs or so and not pushing it too hard. And I think the back isnt even too bad for my weight.

I'm wondering that if I was to change the fork oil it might assist in the rebound damping and stop this bouncing

 

[Marthy]

By changing the rear spring to one that is rated for my weight, I actually removed the pogo effect that the stock spring was giving me. The dampening did not change but it seems adequate for the heavier spring in this application.
I only adjusted the preload to set the sag to 20mm.

Here we go... this is the right way to do it. If the spring rate doesn't suite your driving style or weight with the recommended sag, change the spring, not the preload! Good work. I will look into it too. I tried my bike at P2 and it feel better. (I'm 160 lbs without gears) I need to double check the sag with somebody now... just learn that one with the video. The front springs are a bit on the soft side for hard braking. Do you know what oil weight is in the STD shocks? What's available? Thanks!