Front suspension suggestions...

Hi all,

I've read the many Racetech springs, 10/15wt oil threads, and am pretty much set to pull the trigger (my seals may be leaking so its a good time)... BUT I'd love to hear from people who ride in cities w/ not-so-awesome roads.

I'm a little paranoid that a .90 spring and 15wt oil will feel like stiff cr@p over potholes, cracks, bumps, etc. BTW I am ~180lbs.

Any input greatly appreciated!

Thanks! :rockon:

metallicat said:

Hi all,

I've read the many Racetech springs, 10/15wt oil threads, and am pretty much set to pull the trigger (my seals may be leaking so its a good time)... BUT I'd love to hear from people who ride in cities w/ not-so-awesome roads.

I'm a little paranoid that a .90 spring and 15wt oil will feel like stiff cr@p over potholes, cracks, bumps, etc. BTW I am ~180lbs.

Any input greatly appreciated!

Thanks! :rockon:

Click to expand...

Go for the R6s forks:thumbup:
I think the .90 and 10wt oil would be good. I had the .95 and 15wt oil, seemed smooth but limited in response.

I did .90 springs and put 5w oil in. I really like it. I don't drive on the smoothest roads either. I'm also the same weight as you.

Fwiw R6's have 0.88kg/mm springs which is what i run (the complete fork) so 0.90 should work good w/10wt for basic riding/commute as primary use. If you want more from the bike and/ride more aggressive, get the R6 fork or plan on installing emulators w/the new springs.

I drive on a lot of bad roads and use .90 with 5wt. I tried 15wt like many people use but for me it slowed the fork action to much, it couldn't react quick enough on bad roads.

hi , bit new to this.

I had a fz6 04 and loved it but when you start to push it on the front its not very stable and bounces badly. after selling it and a few years trying a few bikes wanted an other fz6 as they are all day comfy and a blast to ride.

New bike is a 2008 fz6 s2 and loved it from day one but the front is still the weak point. looked on line for a fix but changing springs and oil was the best advice out there, but on a site some one suggested MATRIS INTERNALS for the fork. about £300 but the difference is amazing you can now push the front and keep a constant line through the corners even on uneven surfaces.
the come with a spring and oil for your wait and driving type and you can adjust the preload with the new adjusters that replace the originals.
A very good upgrade and worth the extra cost.
Have a look
CarpiMoto - Matris Fork Cartridge Kit for Yamaha FZ6/FZ6 S2/Fazer 04- rider weight Kgs 70-85 (154-187 lbs)

brian0798 said:

hi , bit new to this.

I had a fz6 04 and loved it but when you start to push it on the front its not very stable and bounces badly. after selling it and a few years trying a few bikes wanted an other fz6 as they are all day comfy and a blast to ride.

New bike is a 2008 fz6 s2 and loved it from day one but the front is still the weak point. looked on line for a fix but changing springs and oil was the best advice out there, but on a site some one suggested MATRIS INTERNALS for the fork. about £300 but the difference is amazing you can now push the front and keep a constant line through the corners even on uneven surfaces.
the come with a spring and oil for your wait and driving type and you can adjust the preload with the new adjusters that replace the originals.
A very good upgrade and worth the extra cost.
Have a look
CarpiMoto - Matris Fork Cartridge Kit for Yamaha FZ6/FZ6 S2/Fazer 04- rider weight Kgs 70-85 (154-187 lbs)

Click to expand...

Thanks for the Follow Up! How long was the install and how difficult would you rate it? Please provide your Basic confidence & mechanical ability for others so they know if they can tackle this one.

Any other details on ride quality after install?

Thanks!

I use 20wt in one leg and 30wt in the other (= 25wt....yes you can do that with oil and springs) with 1.0kg/mm racetech srings. The front is WAY too soft still. I bottom out even with 23mm of static sag. I'd rather have the stock progressive weight springs or hyperpro's.

Fork oil is there to give you proper dampening, don't go too light with it. AT LEAST 15wt. Even that is super bouncy still.

Hi I am by no mean a mechanic , can do basic
Stuff . Whole job took about 5 to 6 hours.
Really makes a massive difference
So much better feel from the front .

The Gold Valve Cartridge Emulator by RaceTech... Has anyone kept the stock fork springs and simply added the Gold Valve with maybe 10wt oil? I know that just replacing the stock oil will make some change in the front end, but probably not enough for what the OP is looking for.

dpaul007 said:

I did .90 springs and put 5w oil in. I really like it. I don't drive on the smoothest roads either. I'm also the same weight as you.

Click to expand...

Did the same ^ as you want the fork to be able to follow the irregularities in the road not bounce off them.

motojoe122 said:

Go for the R6s forks:thumbup:
I think the .90 and 10wt oil would be good. I had the .95 and 15wt oil, seemed smooth but limited in response.

Click to expand...

Exactly. Having done both the R6 forks are well worth the effort.

Or install the RT emulators and springs.

Sent from my SAMSUNG-SGH-I747 using Tapatalk 2

JeffD said:

The Gold Valve Cartridge Emulator by RaceTech... Has anyone kept the stock fork springs and simply added the Gold Valve with maybe 10wt oil? I know that just replacing the stock oil will make some change in the front end, but probably not enough for what the OP is looking for.

Click to expand...

I've done that on a Yam XV920R and a Yam RZ350 but springs ans emulators. The outcome is very good and it is an easy mod vs. the R6S fork. Both of those forks are skinny; 37mm & 35mm. It the stock spring is the correct you should be fine.

Sent from my SAMSUNG-SGH-I747 using Tapatalk 2

JeffD said:

The Gold Valve Cartridge Emulator by RaceTech... Has anyone kept the stock fork springs and simply added the Gold Valve with maybe 10wt oil? I know that just replacing the stock oil will make some change in the front end, but probably not enough for what the OP is looking for.

Click to expand...

All those do is blow apart the compression valve if the velocity gets too high. When you drill out the damper rod bottom the new compression holes are in the upper portion of the emulator stack. They're too big for 10wt oil and so are the factory rebound holes. Doing what you're asking is a giant and complete waste of money.

The suspension will still bounce way too much and those emulators will never need to blow apart (cause the velocity will never be high enough with the thin oil) even if you use the lightest springs and do a half turn of the emulator preload.

The proper weight oil for the FZ6 is 25wt...NOT 15wt btw. Where that myth came from IDK but it's simply not true if you know even the slightest basics of suspension setup. When you set the system up the right way the emulators really shine....otherwise they're totally pointless.

ped said:

All those do is blow apart the compression valve if the velocity gets too high. When you drill out the damper rod bottom the new compression holes are in the upper portion of the emulator stack. They're too big for 10wt oil and so are the factory rebound holes. Doing what you're asking is a giant and complete waste of money.

The suspension will still bounce way too much and those emulators will never need to blow apart (cause the velocity will never be high enough with the thin oil) even if you use the lightest springs and do a half turn of the emulator preload.

The proper weight oil for the FZ6 is 25wt...NOT 15wt btw. Where that myth came from IDK but it's simply not true if you know even the slightest basics of suspension setup. When you set the system up the right way the emulators really shine....otherwise they're totally pointless.

Click to expand...

First of all, Thanks for letting me know BroHam! 2nd, I have very little understanding of true suspension operations & characteristics so I greatly appreciate an shared knowledge.

Referring to the Fork Oil weight, I've read rumors about stock oil being very thin. If I simply replace the existing FO with a slightly thicker oil, will I suffer in the Rebound department? I have also read that different Mfg's oil weights differ slightly.

Ped, or anyone of course, do you have a suggestion for super cheap slight changes for the forks before saving up for the bigger changes like new springs, possibly R6 forks, etc.? Much appreciated

Unless the kit is specifically designed for 25wt oil, i.e. having very large orifices to pass oil through I'm having a hard time believing this is going to work.

Adding emulator gives you control over the compression rate as its no longer a fixed orifice controlling oil flow. Its an actual valve which you can vary the flow rate through by changing the pressure applied. Again, the manufacture has established a ball park figure for viscosity. One which I doubt is 25wt but that can vary depending on who's product you buy. Once the emulators are installed per manuf instructions the rebound rate is now being controlled by fixed orifices. Thus the viscosity is critical to operation. To thick/heavy and it cavitates aerating the fluid making bubbles and increasing the fluid temperature.

This is one of the more thorough reads on damping rod forks. Sport Rider Technicalities-Damping rod forks and the Race Tech Gold Valve Emulator Take a look. Also Amazon of all places has some emulators for $120 or so - might be worth trying out. (FEGV S4101 Gold Valve Emulators 41mm Forks w/Adapters).

Here is a PDF about this emulator in another application. http://racetech.com/download/IP FEGV S4101V4 Honda V4.pdf It shows the basic install. Ours would vary slight but give it a read and see if its within your means to do this.

A little excerpt from the sport rider link above...
((PASTE))
There are four tuning variables for damping: oil viscosity, which is selected to properly control rebound damping; the preload on the Emulator spring, which controls low-and mid-speed damping; the Emulator's spring stiffness itself, which controls high-speed damping; and the bleed-hole size, which affects low-speed damping. This gives the tuner tremendous control of the damping curve and the Emulator is simple to install and adjust. The net effect is a damping curve that emulates or copies the damping curve of a cartridge fork, hence the name Gold Valve Cartridge Emulator.

Read more: Sport Rider Technicalities-Damping rod forks and the Race Tech Gold Valve Emulator

If I were in need, this might be a viable option - be warned that the tapered coil spring may not fit over these emulators...

JeffD said:

First of all, Thanks for letting me know BroHam! 2nd, I have very little understanding of true suspension operations & characteristics so I greatly appreciate an shared knowledge.

Referring to the Fork Oil weight, I've read rumors about stock oil being very thin. If I simply replace the existing FO with a slightly thicker oil, will I suffer in the Rebound department? I have also read that different Mfg's oil weights differ slightly.

Ped, or anyone of course, do you have a suggestion for super cheap slight changes for the forks before saving up for the bigger changes like new springs, possibly R6 forks, etc.? Much appreciated

Click to expand...

No problem!

rebound is what you set the oil weight for. its compression you'll consider secondary.

cheap reworki is ti put heavier oil in and some washers under the fork cap to raise the sag if you're over 170lbs or so.

FinalImpact said:

A little excerpt from the sport rider link above...
((PASTE))
There are four tuning variables for damping: oil viscosity, which is selected to properly control rebound damping; the preload on the Emulator spring, which controls low-and mid-speed damping; the Emulator's spring stiffness itself, which controls high-speed damping; and the bleed-hole size, which affects low-speed damping. This gives the tuner tremendous control of the damping curve and the Emulator is simple to install and adjust. The net effect is a damping curve that emulates or copies the damping curve of a cartridge fork, hence the name Gold Valve Cartridge Emulator.

Read more: Sport Rider Technicalities-Damping rod forks and the Race Tech Gold Valve Emulator

If I were in need, this might be a viable option - be warned that the tapered coil spring may not fit over these emulators...

Click to expand...

Yes sir FinalImpact, I spent the better part of my day reading the SportRider Suspension articles, more than one mind you! Thaks for the links. Paul Thede & Dave Moss are Suspension Machines! Heck no, I still don't fully understand the details and may never, but I certainly have a much better grip on the basics.

The viable option you mention... it's based on keeping the stock springs as I thought I might try but will not now. From what I'm gathering, the Emulators will only function properly in new springs?

Alright, here's where I'm starting: I'll change the stock fork oil first since it's never been done. May not "need" it, but that's where I'm starting. If I'm not at all pleased with that or if I screw myself on Rebound, which I DO NOT want to do, I'll most likely look into the RaceTech springs for my weight, or possibly HyperPro Progressive springs. Thanks again for the excellent info!

Someone said the proper weight oil is 25wt for the Fz6. That is not true yamaha uses Yamaha Suspension oil 01 They say it's 0wt but many other fork oil manufactures recommend using there 2.5 to 5wt.