FJ-09 Shock vs FZ-09 Shock Valving Comparison

[norwest]

Just in case a member here would like to see what differences exist between the FZ-09 shock and the FJ-09 shock both OEM.
 
Here is some info on the comparison between the OEM FZ-09 shock and the OEM FJ-09 shock. Both use the same piston internally and neither have any type of bleed drilled into the piston itself. Both are IFP design and both have the same shaft travel. The spring remains unchanged from the FZ-09 to the FJ-09 as they were close enough in rate FZ-09 9.8 kg/mm FJ-09 9.9 kg/mm.
 
Here are the shims stacks in OEM configuration.
FZ-09 Compression
34 0.15
34 0.15
32 0.1
32 0.1
30 0.1
30 0.1
28 0.1
24 0.1
22 0.1
18 0.15
16 0.68
 
 
FJ-09 Compression
34 0.2
34 0.2
34 0.2
34 0.2
34 0.2
34 0.2
34 0.2
34 0.2
32 0.2
28 0.2
26 0.2
24 0.2
20 0.2
18 0.2
15 0.69
 
Graph showing the different compression damping curves:

 
FZ-09 Rebound
32 0.15
32 0.15
32 0.15
32 0.15
32 0.15
30 0.25
30 0.25
28 0.25
28 0.25
26 0.25
26 0.25
24 0.25
22 0.25
20 0.25
18 0.69
18 0.69
18 0.69
18 0.69
 
FJ-09 Rebound
32 0.3
32 0.3
32 0.3
32 0.3
32 0.3
32 0.3
30 0.3
30 0.3
28 0.25
26 0.25
24 0.25
20 0.68
 
Graph showing the different rebound damping curves:

 
IMO the OEM FJ-09 shock seems a bit overdamped especially since it has the same rate spring as the FZ-09.
 
Hope this sheds some light on the differences between the two shocks.
 
Terry
 

[ULEWZ]

Those graphs clearly show a difference, but to a Layman like me, just looks pretty. Could you possibly give a description of what the higher vs lower numbers mean, what is desired, and how to get it? At what point is it a lumpy ride, and at what point is it mushy. Thanks.

[norwest]

Those graphs clearly show a difference, but to a Layman like me, just looks pretty. Could you possibly give a description of what the higher vs lower numbers mean, what is desired, and how to get it? At what point is it a lumpy ride, and at what point is it mushy. Thanks.

Ok I am only going to show the compression side as once you understand what the colorful lines are showing then the rebound or any other shock or fork for that matter will follow suit. 
The question on what is a lumpy ride and what is a mushy ride is dependent on rider weight, leverage ratio, tire size, rider preference so in all honesty that is a tough question to answer as there are several variables. 
 
So in the graph on the left side it is showing Damping Coefficient [lbf-s/in] which in technical terms would be "The damping coefficient is simply defined as force produced by the shock divided by the shaft velocity" so basically how much damping the shock creates with a given shaft velocity.
 
Suspension velocity is basically how fast in [in/sec] the shaft is moving, to give you an idea if you hit a 2" bump at 70 MPH with a 18" tire you would see roughly a 360 [in/sec] shaft velocity. Once again there are some other variables that come into play so that may change depending on leverage ratio, actual tire diameter and shape of the bump.
 
Ok on to the graph, My example is going to be both FJ-09 shocks to keep an apples to apples comparison. What I did on the red line is I removed 3 face shims (Shims that seat against the face of the piston, Which in this case would be (3) 34 x .2 shims. I then took the rebound clicker out from 10 clicks out to 13 clicks out from the fully seated position. if you had a line that went from the bottom left to top right that would be very progressive damping, If the line went straight across then that would be linear damping. So what we see here is Digressive damping which gives an initially stiffer damping then as the shaft velocity goes up the damping becomes softer. This is a good combination as riding down the road you want a good feel to the road but when hitting a bump you want the suspension to respond to that bump without being harsh or mushy.
 
By moving shims around in the stack or using thicker or thinner shims or different diameters you can tailor the damping to the riders preference. You could create a two stage stack where you have x amount of face shims and then a smaller thinner shim which would be the cross-over and then the hi speed stack and this would give you a softer mid speed with a stiffer hi speed. There are so many variables when it comes to valving that it is crazy, We have shims in .10 , .15 , .20 , .25, .30 thicknesses and diameters of 1mm increments so the configurations are endless on how and what you want from valving your suspension. We can also preload the stack so you place a hoop shim or ring shim in the stack at a position you select and that will even give you more lo speed damping and once it opens then it keeps the softness for compliance over the bumps. A couple riders one in Ireland and one in Australia love the preload stack setup for the rough roads.
 
Also you can see that adjusting the rebound affects the compression as well as the orifice in the middle of the shaft flows both directions. You could install a rebound separator valve or device which would make the flow asymmetric. So in the graph the initial peak on the red line is coming from the extra 3 clicks that I opened the rebound adjuster to as well as the reduction in face shims. The reduction in 3 face shims created the lower damping curve from mid speed to hi speed. So the shim, adjuster circuits overlap and create a transition sort of speak so you get a smooth damping curve.
 
Anyway I hope I explained it so you have a basic understanding of what is going on and what suspension tuners try to achieve both by listening to the riders needs as well as drawing from their experience on how to implement what the rider is asking for. 
 
 
 

[bubba]

This seems to be a popular and inexpensive rear shock mod for the FZ-09. Should also work for FJ-09, no?
http://www.fz09.org/forum/32-yamaha-fz-09-guides-how-s/1216-fz-09-rear-shock-conversions.html
google fz-09 zx6r rear shock replacement lots of hits
 

[pattonme]

it's only a useful upgrade if you get it rebuilt and sprung correctly. If you're in the target weight demographic you save the $70. If not, buy the spring. Norwest can fix you right up.

[Buggy Nate]

I thought the FJ/FZ shocks weren't rebuildable? And that they were a throw away? I agree with the overdamped feeling too on the shock, the forks don't have enough in my opinion.

[norwest]

I thought the FJ/FZ shocks weren't rebuildable?

Seems you read incorrect information or maybe they meant it is not rebuildable in OEM form. 

[Buggy Nate]

I thought the FJ/FZ shocks weren't rebuildable?

Seems you read incorrect information or maybe they meant it is not rebuildable in OEM form.

It was on here somewhere that they were a throw away item. I'd prefer to have a tinker myself with the valving. Looking at the racetech option for the forks but haven't found much on the aussie site for them. Good to know I can do something with the shock. I just bought all the re gassing tools to do my dirtbikes shock.

[adjuster]

Interesting. I've owned both bikes, and the FZ was much softer than the FJ feels. But in a bad way. the FZ was so "soft" it just pogo'd around, a good hit of throttle would set the rear end down like a low rider, while the front forks were so soft they would just dive for cover if you even thought about using the front brakes....
 
The FJ? Not in any way like the FZ. (I bought a used GSXR shock with the high/low compression and rebound adjustments.. just because the FZ was so bad suspension wise.)
 
But I have not installed it on the FJ, it's not bad stock. And I have preload on max for both bikes rear, had preload max on the front for the FZ, but it's "stock" on the FJ. And does not dive like a submarine's just seen a ASW plane either....
 
Problem is, the GSXR shock I found is slightly shorter than the stock one. About 1/2" to be exact. It would lower the bike slightly, and I don't want that.
 
What I've done on past bikes is just make up new links to get the rear suspension where I want it, and the "aftermarket" shock to fit in place. On the FZ1 it was new 3 point links, and an upside down R1 shock, worked excellent with the stock FZ1 spring on there, but dang, it was not easy to get that longer spring onto the R1 shock. You need spring compressors, and the right string of swear words in the correct sequence to get it to work..
 
ON the FJ, I've just been riding the bike. But I'd like eventually to make up some longer links, should be simple, they are much less work than on the FZ1, and swap out a higher rate spring for the rear, while I'm pretty happy with the front? Perhaps slightly more rate there would be fine, but I have not needed to even crank down the preload up front, so it's closer than it should be by the charts.
 
Perhaps next winter, pull them off and see if Matt can do his magic on them. Then again, while the Pound Sterling is in the dumps to the dollar, buy the Nitron shock while the price should be lower?