YAST- Setting up Hyperpro progressive springs

Yet Another Suspension Thread

Background:
I'm trying to tune my suspension. Front feels a bit firm. Rear unbalanced with front and on the softer side.

I had compared people's feedback on Racetech springs and Hyperpro setups. I went with Hyperpro because of positive reviews like this one and wanting a smoother ride vs. riding it hard.

I've already installed the springs front and rear along with the 15w oil. It rides much better than before (had been way too harsh.)

Today I took some initial measurements after the epic fail of FinalImpact trying to help me the other day. (Bolt replaced, thanks bud.)

Front
Static sag: .25" = 6.35mm (Hyperpro recommends 24mm)
Rider sag: .75" = 19.05mm
Total sag: 1" = 25.4mm (30-35mm recommended for street)

Rear
Static sag: 1" = 25.4mm (Hyperpro recommends 10mm)
Rider sag: 1" = 25.4mm
Total sag: 2" = 50.8mm (30-35mm recommended for street)

• Measurements made without gear (160lb) for now and a low tank of gas.
• Looks like the rear is way too soft and the front is a little on the harder side.
• I'm looking to get it into the 30-35mm range recommended for street.

Attached are Hyperpro's instructions specific to the FZ6. The static sag adjustments are way off from my bike and I do have preload set to #2 per the instructions.

Tomorrow I'll set the preload to #3 or #4 and get some gas then measure again.

If anyone has any suggestions on fork preload spacer adjustments I'd appreciate it. Are different length sets available? Just cut them down?

Hi Darius,

First of all I'll try to explain very difficult arguments with my limited English... So assume I'll make some languaje mistakes...

I allways use a secuence to fine tune the suspensions:

1.- Choose your geometry
2.- Choose the correct springs for your weight and riding style
3.- Choose the correct suspension oil and adjust hydrahulics systems

Each of this points is going to affect the others, so this order will make the best sense if you have limited resources to apply.

1.- There is only one point to adjust in our Fz6: The position of the bars in the triple clamp. Try different values and choose your preference. Going more than 12mm up will make the bike unstable and nervous at high speeds.

2.- You want to use the maximum length available in both axis, this is the way the suspensions perform better. There is a method to check if you are using all the lenght available: Put something (¿a bridle?) on the fork bar and the same in the shock, go and ride it hard, if the "indicators" are near the end of the bar (or the shock) you need stronger spring, if not choose a softer ones. Trying to avoid "reasonable" diving in your front is not the way, the fork must dive under heavy braking but maintainning some suspension.

3.- Once you have the correct springs you can go to choose the correct oil, don't look only at the weight (Sae), please choose the correct viscosity (Cst grade), I'm using now 25 to 30 Cst in Fz6 S2 with good results, the bike came with Kayaba01 oil wich may be something like 16 Cst...

Preloading a Spring doesn't make it stiffer, you only make it begin working at a higher load, set the sag after having choose the previous parameters.

Level fluid is another variable than can affect the spring rate and the rebound parameters, higher means some air spring effect and some added rebound.

Having said this, as a starting point, I would change your front oil level to a bit less and check the performing.

V'sss

seneca said:

Hi Darius,

First of all I'll try to explain very difficult arguments with my limited English... So assume I'll make some languaje mistakes...

I allways use a secuence to fine tune the suspensions:

1.- Choose your geometry
2.- Choose the correct springs for your weight and riding style
3.- Choose the correct suspension oil and adjust hydrahulics systems

Click to expand...

Thanks, Seneca. I appreciate your help.

1. Geometry-wise I raised the forks 5mm as directed by Hyperpro. Perhaps the springs make the front end sit higher and this change is to cancel it out.
2. The springs are progressive, but pretty sure they're heavier than stock. No choice in weights.
3. I'm using 15W oil supplied by Hyperpro in the kit. Some research said that oil levels only impact the fork in the final 30% of travel.

I set the preload to 3 on the back. Static sag stayed the same and no 2nd pair of hands to measure rider sag.

I remeasured the front with full gear, full tank, after a ride and front measurements remained the same. I'm using a zip tie.

• According to the owner manual front and rear have 130mm of travel.
• The target sag is 30% of travel which would be 39mm front and rear.

~26mm in the front = 20% of travel
~50mm in the rear = 39% of travel
Very uneven!

During my ride I had to brake on a steep downhill for a red light and that put the forks through 3.5" of travel (69%).

Now to figure out how to adjust the front. Not looking fwd to removing the handlebars, fork caps for each adjustment.

Chris,
You said you put progressive springs in both front and rear, can you list what rates they are?

As I know it, there are no know lengths of spring spacers for the front. RaceTech sells tubing you can cut to length other than that, you could use PVC to establish ride height and do a test drive. Some leave it in but I wouldn't. Besides, it sounds like the back is the issue not the front.

Can you tell are you ever bottoming out the suspension? I'd like to know the new spring rates - and you might have to bump the rear to max setting to get the sag needed (#7).

FinalImpact said:

Chris,
You said you put progressive springs in both front and rear, can you list what rates they are?

As I know it, there are no know lengths of spring spacers for the front. RaceTech sells tubing you can cut to length other than that, you could use PVC to establish ride height and do a test drive. Some leave it in but I wouldn't. Besides, it sounds like the back is the issue not the front.

Can you tell are you ever bottoming out the suspension? I'd like to know the new spring rates - and you might have to bump the rear to max setting to get the sag needed (#7).

Click to expand...

Regarding the front:
The rate is progressive so there is no rate right? One spring fits all rolleyes so I got what was in the kit. I'd have gone Racetech if I'd known a bit more about suspension at the time.

I'm pretty sure spacers are in there stock as they're referenced by the Hyperpro instructions as a 130mm spacer. They're also in the Yamaha fische (18,38).
The spacers are just $5 each from Yamaha if I could cut them straight into diff lengths.
I don't see spacers in the list of parts offered by Racetech here

Rear:
I'm sub 160lbs and don't ride hard- not bottoming out the rear. I'll keep going through the preload settings to get the sag down a bit.

darius said:

Regarding the front:
The rate is progressive so there is no rate right? One spring fits all rolleyes so I got what was in the kit.

The spacers are just $5 each from Yamaha if I could cut them straight into diff lengths.

Click to expand...

Progressive springs come in different rates. They will have a starting rate and finishing rate. But being true progressive ever changing through the travel. I believe our stock spring is duel rate.

And for $5 you can go to the hardware store and get like 6ft of pvc.

iSteve said:

Progressive springs come in different rates. They will have a starting rate and finishing rate. But being true progressive ever changing through the travel. I believe our stock spring is duel rate.

And for $5 you can go to the hardware store and get like 6ft of pvc.

Click to expand...

Couldn't find any info on their website on rates.


Just thinking- I'm looking to raise the forks further in the triple. This will add weight to front end and should add to the sag.

I've got the rear preload set to 5 now and that's feeling pretty good.

I see where you're going with changing the bias "for and aft" but its going to make the bike noticeably twitchy way before the sag value declines. In short, Moving the triple won't change the sag appreciably. Although its a product of load, the static preload imposed within the fork itself, is what you need changed.

Do you have the part numbers for the springs? Can you list them Here?
oh - yes the oem front springs are progressive. The rear is not.

FinalImpact said:

I see where you're going with changing the bias "for and aft" but its going to make the bike noticeably twitchy way before the sag value declines. In short, Moving the triple won't change the sag appreciably. Although its a product of load, the static preload imposed within the fork itself, is what you need changed.

Do you have the part numbers for the springs? Can you list them Here?
oh - yes the oem front springs are progressive. The rear is not.

Click to expand...

I understand the steering will be quicker and that's the main reason for raising the forks. The added weight would be a side benefit if it works out.

I have the stock forks. With R6 forks, aren't they 1/2" shorter? And often they get raised even further.

Would raising stock forks 12.5mm produce the same geometry as the R6 fork swap?



Hyperpro progressive part numbers:
Front: SP-YA06-SSA017
Rear: SP-YA06-SSB017
Full set: SP-YA06-SSC017

http://www.epmperf.com/price-lists/Springs 01-13.pdf

I emailed them asking for the spring rates.

If you like how it falls in now I'd open the fork and chop your spacers (5 - 6mm) to get you at least 31 mm sag. Fwiw: My stock forks were 44 mm sag which as you pointed out consumed allot of the forks travel.
Yes, R6 are shorter and I find 31mm sag with 8mm up the clamp to turn in nice.

FinalImpact said:

If you like how it falls in now I'd open the fork and chop your spacers (5 - 6mm) to get you at least 31 mm sag. Fwiw: My stock forks were 44 mm sag which as you pointed out consumed allot of the forks travel.
Yes, R6 are shorter and I find 31mm sag with 8mm up the clamp to turn in nice.

Click to expand...

So if the stock forks are 12.5mm longer than R6 forks and you've raised yours 8mm, would a 20.5mm rise with stock forks yield the same geometry as your setup?

This is theory- I'd make adjustments incrementally.

Hyperpro wrote back with the unlisted spring rates:

Front: 8.5 – 15.00 N/mm
Rear: 147 – 227 N/mm

Since I'm nearly ready to try a different preload adjustment, I've been checking on the fork oil..

Yamaha service manual states to use "Suspension oil 01". Apparently this is a 0W oil. This is in contrast to the 15W I'm running now provided by Hyperpro in their package.



Yamalube's site stating that this is the oil to use in the FZ6 for optimal flow rate: Yamalube

Also found this hyperpro thread suggesting that 15W is much too heavy for the fork to work correctly:
http://www.600riders.com/forum/fz6-mods/43796-hyperpro-springs-hard.html

The Yamalube 01 is about $40 shipped if you can find it. That's for 1 liter!

I've ordered up Silkolene Pro RSF 2.5w which is supposed to be the closest thing out there in viscosity to the 01 as recommended by other forums.

So what do you like and want vs what you have and need? Sounds like you need the emulators to get control of the situation.

I'm guessing my bike would jar your teethies clean out, but I weigh more and ride for a different reason. I'm not after the "town car" ride, for me its all about controlling the motion which mine does well at both ends huggin the road. Its predictable which is was not before I broke the Tamper seals and changed things up a bit...

FinalImpact said:

So what do you like and want vs what you have and need? Sounds like you need the emulators to get control of the situation.

I'm guessing my bike would jar your teethies clean out, but I weigh more and ride for a different reason. I'm not after the "town car" ride, for me its all about controlling the motion which mine does well at both ends huggin the road. Its predictable which is was not before I broke the Tamper seals and changed things up a bit...

Click to expand...

I'm not expecting miracles from the stock forks and shock. I just want to set it up properly and get some confidence in the corners.

The bike had been feeling like it just did not want to turn. Way too much steering effort.

Lowering the front another 5mm helped, but that adjustment may have been simply compensating for the poor suspension setup.

We'll have to swap bikes when I'm done tuning. Maybe we'll both learn something. :thumbup:

Good info on damping, suspension oils:
Peter Verdone Designs - Low Speed Damping

In his table it shows a dramatic difference in the viscosity between what Yamaha design their forks for and the range of 15W oils.

As I understand it, the case for 15W oil is that it acts as a poor man's damper, but I'm thinking it's slowing down the fork so much that it cannot react fast enough to bumps leading to harshness.

If we're experiencing excessive front end dive, the springs are likely too light vs. needing to up the oil weight/viscosity.

darius said:

Good info on damping, suspension oils:
Peter Verdone Designs - Low Speed Damping

In his table it shows a dramatic difference in the viscosity between what Yamaha design their forks for and the range of 15W oils.

As I understand it, the case for 15W oil is that it acts as a poor man's damper, but I'm thinking it's slowing down the fork so much that it cannot react fast enough to bumps leading to harshness.

If we're experiencing excessive front end dive, the springs are likely too light vs. needing to up the oil weight/viscosity.

Click to expand...

This is the exact reason I upgraded my springs and stuck with 5w fork oil. :thumbup:

dpaul007 said:

This is the exact reason I upgraded my springs and stuck with 5w fork oil. :thumbup:

Click to expand...

Thanks for the feedback! Which springs did you go with? Did you set the sag?