***Leathernecks rail ***

[Leatherneck]

Tore the shocks apart, time to stiffen up rebound and get rid of the twerking. With the numbers on the cap, what should I be going to? Have more learning to do.

IMG_0184.JPG

IMG_0185.JPG

IMG_0186.JPG

[no1clyde]

Not sure what the numbers mean but if it were mine I would measure the thickness of the rebound stack (the side by the nut) and get the next thicker set and test again noting the difference and then think about if that did what you hoped it would. BTW what do they measure? In your pic is that the rebound or compression, it looks like a flutter stack and if it is rebound I would try a straight stack that is one size thicker for rebound and test but that is just what I would try, doesn't mean it will work LOL.

Edit what I mean by a straight stack is no flutter and all one size thicker but they are still pyramid shape, hope that helps.

Ed

[Leatherneck]

Ed I do appreciate the help. I will measure the shims I have so I will know where to start.

[Piledriver]

Put it all in a spreadsheet embed the pictures..
Looked like you have the Fox low flow pistons...
Are the piston bleeds drilled/plugged or open?

[Leatherneck]

Put it all in a spreadsheet embed the pictures..
Looked like you have the Fox low flow pistons...
Are the piston bleeds drilled/plugged or open?

Have a example of said shim spreadsheet? I'll post shim stack dimensions in a bit. What say you on the piston, looks drilled to me

IMG_0188.JPG

Had a good ride but going through deep whoops the tail would spring up, at 12:40 you can see some of it. https://www.youtube.com/watch?v=A7W_0Af10tc
Nut
Dia-Thickness
00.79-.0160
00.79-.0065
00.79-.0165
01.09-.0065
01.35-.0080
01.42-.0070
Piston
00.94-.0020
01.60-.0040
01.42-.0055
00.80-.0055
01.42-.0125
01.35-.0140
01.95-.0120
00.95-.0125
00.80-.0165

BTW, Turbo is going back on.

[Piledriver]

Re: No magic spreadsheet, all i did was paste like what you posted and the pics into a spreadsheet for future reference.
Makes it easier to go back/see where you have been.
I'm only doing it for on-road, so may be of limited help.

May have bottomed out there?
The gopro is much more useful if you can see the tire and how it follows the ground.

It doesn't look like you have many effective shims, no specs or anything came with the shocks?

The tiny little holes that go through are the bleeds.
Sometimes they will be tapped and blocked with tiny setscrews.
Do note the piston has a very definite top and bottom... The smaller passage to the shims should be rebound (towards nut)
That first small shim against the piston compression side also effectively creates a ~huge bleed, it spaces the first large shim off the piston...(negative preload)
Bleed sort of sets a minimum flow, helps smooth small choppy stuff, but that neg preload may make it too cushy.

I think those are the std high flow pistons now after some research, there sadly isn't a really good photo reference for anything but Ohlins pistons.
Ohlins also has a book with hundreds of dyno runs worth of info for each piston and shim stack combo, good reading if you are looking at DIY tuning in any case, Penske has some tuning info too.
Google for "Ohlins_X_Stacks_Book.pdf"
All these shocks work about the same way, so its a fine example of something.

Here are the "low flow" pistons used in some Fox 2.0 track shocks and probably some street/"factory" shocks:
Larger % open area but much smaller shaft, and probably sharper angles, changes the high flow response.

[no1clyde]

OK Leather the way I hear you is the compression is fine just the rebound kick is bad so rebound is all you are working on I think. The 4 little holes in the two sides are what would be bleed holes if they were drilled and I don't think yours are but Pile has a point but not a problem to you. The rebound stack seems to have only 3 shims doing anything and the other 3 by the nut seem to be just taking up room. I think if it were mine I would go to a fox #35 or #40 for rebound and put them in and test. I am computer challenged and a this link is the best I can do.

http://www.ridefox.com/dl/offroad/FOX_OR_20_VALVING.pdf

I would just say put in a #40 stack in each on rebound and give it a go and leave the compression the way they are as you are happy with compression and test. You do have alot of bleed in the compression side but if it is working well that way go with it.

What are your spring rates, the rebound is what controls the unloading of the springs and when you go heavier on springing you need to up the rebound too. Don't get discouraged if the first try is not right, just try to feel what changed and see if you went too far or not far enough and adjust from there

Ed

[Leatherneck]

Re: No magic spreadsheet, all i did was paste like what you posted and the pics into a spreadsheet for future reference.
I will do that, thought at first it was for STF's use.

I'm only doing it for on-road, so may be of limited help.
Any education is a big help and I do appreciate it.

May have bottomed out there?
I remember going into the dip and it did compress but I don't remember it hitting, just the feeling of the butt coming up in the air was a bit unsettling. It happened on several occasions but this was the biggest hop

The gopro is much more useful if you can see the tire and how it follows the ground.
When I test them I will move the camera to focus on the suspension movement for sure.

It doesn't look like you have many effective shims, no specs or anything came with the shocks?
I will see if I can find the paperwork

The tiny little holes that go through are the bleeds.
Sometimes they will be tapped and blocked with tiny setscrews.
Do note the piston has a very definite top and bottom... The smaller passage to the shims should be rebound (towards nut)
That first small shim against the piston compression side also effectively creates a ~huge bleed, it spaces the first large shim off the piston...(negative preload)
Nothing I see shows a reason for the offset shim by the piston.
Bleed sort of sets a minimum flow, helps smooth small choppy stuff, but that neg preload may make it too cushy.

I think those are the std high flow pistons now after some research, there sadly isn't a really good photo reference for anything but Ohlins pistons.
Ohlins also has a book with hundreds of dyno runs worth of info for each piston and shim stack combo, good reading if you are looking at DIY tuning in any case, Penske has some tuning info too.
Google for "Ohlins_X_Stacks_Book.pdf"
All these shocks work about the same way, so its a fine example of something.
I like a fine example of something, sometimes useful

Here are the "low flow" pistons used in some Fox 2.0 track shocks and probably some street/"factory" shocks:
Larger % open area but much smaller shaft, and probably sharper angles, changes the high flow response.

OK Leather the way I hear you is the compression is fine just the rebound kick is bad so rebound is all you are working on I think. Yes sir that is what I need to fix. The 4 little holes in the two sides are what would be bleed holes if they were drilled and I don't think yours are but Pile has a point but not a problem to you. The rebound stack seems to have only 3 shims doing anything and the other 3 by the nut seem to be just taking up room. I think if it were mine I would go to a fox #35 or #40 for rebound and put them in and test. I am computer challenged and a this link is the best I can do. I will do the #40 stack.
http://www.ridefox.com/dl/offroad/FOX_OR_20_VALVING.pdf

I would just say put in a #40 stack in each on rebound and give it a go and leave the compression the way they are as you are happy with compression and test. You do have alot of bleed in the compression side but if it is working well that way go with it. What do you mean by bleed, the amount that gets by the shim stack?
What are your spring rates, the rebound is what controls the unloading of the springs and when you go heavier on springing you need to up the rebound too. Don't get discouraged if the first try is not right, just try to feel what changed and see if you went too far or not far enough and adjust from there
Ed, thank you for all your help and suggestions.
Ed

You should have a flutter stack built off a standard shim pack, in other words, on the compression side you should have a little shim with a spacer, then a standard stack. On the rebound you should be standard. I don't think a rate plate would help you on the rebound side, but Ed can chim in on that. Maybe with two stage springs you need a little rate control when comming off a hard bump. I don't know.

[Leatherneck]

With the help of you guys and some Googling I am trying to learn.

shock_piston_labeled_sm.jpg

shock_piston_flutter_2.jpg

shock_piston_rate_plate_2.jpg

[no1clyde]

OK Leather in the top pic here you have a normal set of stacks, in the middle pic the compression is a flutter stack WITHOUT the bleed shim you have and by bleed shim I mean the little one that is between the face shim and the face of the piston, that space is the bleed we are talking about If you left out that little shim your compression would be stiffer at low speed damping.And in the bottom pic the rate plate is there to stop the shims from bending any more and that would make it stiffer than if it were not there on high speed damping by forcing the oil through the same size holes and not opening more to flow more.

When I started doing my bike shocks on my bike I would make big changes and carefully ride it to see the differences and change from there, my first go at this I took my shock apart many times looking for what I liked LOL.

Ed

[Leatherneck]

Thank you once again. No good deed goes unpunished, lol. Another question. Shock oil, the stuff I took out looks like Hyd fluid. What weight of shock oil do you suggest, for me I am mostly in high heat temperature.

[Piledriver]

Strictly speaking, the heat doesn't really matter, its the stability of the oils viscosity that is the main issue.

I'm running Redline "Like Water" (~1.7 WT), it allegedly has the lowest viscosity change over temp of any shock oil, very high viscosity index.
Commonly used in NASCAR etc due to its stability.

It will make a given valving/piston setup a little softer, but not as much as you'd probably think.
I drive mine daily from 10F to 110F so I figured I might as well try it. Seems to work so far...

[no1clyde]

I also use very light shock oil. I have been putting Maxma ultra light shock oil in all my shocks, bug and bikes. In your case when you order your valve stacks also order Fox's light shock oil and don't worry about it LOL. One thing I am wanting you to think is this first try is now going to be your starting point or base line as now YOU know what is in there and you now can tune from here so from now on you should use the same oil and gas pressure all the time now and use the stack to change the feel, at least that is how I would feel about it. Hopefully you will be happy with this setup but chances are you will test and think it could be better and be back into them and this is where you want some consistency.

Ed

[bajaherbie]

I have a gallon of FOA( I know, I know) shock oil, looks like cooking oil!


Maybe try some peanut oil? Haha

Sent from my SM-G920R4 using Tapatalk

[Leatherneck]

Thanks guys, appreciate the FOA oil but I'll go ahead and get it from Down South Motorsports, they are getting the #40 shims for me $30 for the two shocks. Yes once I have those I can start finding out what feels right. Let you know what happens.