SFF Tuning tips

NJKawi913
Profile picture for user NJKawi913
Posts
265
Joined
6/5/2017
Location
Somerset, NJ, USA
NJKawi913
Edited Date/Time 4/12/2019 12:27pm
Seeking help from the vital suspension gurus. I have a 2018 KX250F with the SFF forks. In the past I have relied on my local RG3 suspension shop to revalve and set up my bike. However i am making and effort this year to put 20-40 hours on my stock stuff and get it as close to "good" as i can with the clickers before sending it off for professional help. My biggest issue is i only get out to practice a few times a month and with my lack of suspension prowess i can spend a whole day messing with the suspesion going the wrong direction. Any suggestion on the first moves to make would be appreciated. Below are some key variables

190lbs B-rider, riding in the northeast (mostly hard packed, with occasional sand track). My biggest complaint in the 2 rides i has on the bikes is the forks bottoming out, and chatter through braking bumps. My initial thought was to add some preload till they dont bottom out on bigger jumps, then try to slow the rebound down till it's smooth into rough turns. If this sounds like an awful idea let me know


|
Kristen_Valentino 3/30/2019 8:03pm
3/30/2019 8:03pm
They have alot of preload on the spring in stock form, trying backing preload off, turn in compression and add 15cc to fork oil
dirtycummins67 4/1/2019 1:36am
4/1/2019 1:36am
NJKawi913 wrote:
Seeking help from the vital suspension gurus. I have a 2018 KX250F with the SFF forks. In the past I have relied on my local RG3...
Seeking help from the vital suspension gurus. I have a 2018 KX250F with the SFF forks. In the past I have relied on my local RG3 suspension shop to revalve and set up my bike. However i am making and effort this year to put 20-40 hours on my stock stuff and get it as close to "good" as i can with the clickers before sending it off for professional help. My biggest issue is i only get out to practice a few times a month and with my lack of suspension prowess i can spend a whole day messing with the suspesion going the wrong direction. Any suggestion on the first moves to make would be appreciated. Below are some key variables

190lbs B-rider, riding in the northeast (mostly hard packed, with occasional sand track). My biggest complaint in the 2 rides i has on the bikes is the forks bottoming out, and chatter through braking bumps. My initial thought was to add some preload till they dont bottom out on bigger jumps, then try to slow the rebound down till it's smooth into rough turns. If this sounds like an awful idea let me know


The 18-19 Kawi SFF fork is a pain in the ass and really hard to get the perfect setting on in stock form. I would highly recommend calling factory connection and see if they can help you out. I spent a month trying to play with the settings and couldnt find a happy medium.
NJKawi913
Profile picture for user NJKawi913
Posts
265
Joined
6/5/2017
Location
Somerset, NJ, USA
NJKawi913 4/1/2019 5:26am
4/1/2019 5:26am
Kristen_Valentino wrote:
They have alot of preload on the spring in stock form, trying backing preload off, turn in compression and add 15cc to fork oil
I'll give this a try. I went riding Friday prior to see this and ended up adding some preload. It definitely helped the forks from bottoming, However the braking and acceleratoin bumps are giving me issue.
Kristen_Valentino 4/1/2019 6:33pm
4/1/2019 6:33pm
Try backing preload off, and adding a little compression, you can always change it

The Shop

See All »
FFDan
Profile picture for user FFDan
Posts
35
Joined
4/16/2018
Location
Gilbertsville, PA, USA
FFDan 4/12/2019 6:31am
4/12/2019 6:31am
My thoughts and opinions, and I am only pointing out a couple obvious things as I didnt see it in your original post.

1. Set your sag first. At 190 and then adding your gear your rear spring is probably too light for you. I have a KX 450 and had to get a stiffer rear spring to get in the sag range. Race tech has a site that tells you the recommended rear spring for your weight and ability. Once your sag is right and the bike is balanced then you can move on to the air in front forks, clickers on the front, and clickers on the rear shock.

2. I realize I am in the minority, but I like the SFF air forks. It took bit to dial them in but I think they are great. I found most people get wrapped up in adjusting the air when what you should do is find the working spot then use the clickers on the left fork. One of my complaints is the checking air pressures every ride.

3. I found the air pressures are low from the factory. When I first started riding the bike at break in I thought the suspension was way to stiff. I dropped a little air to soften and it got worse. I did a little research and found the key issue was I wasnt running enough air. I was in mid stroke from not enough air. I added lots more air back in and it softened up nicely. Then as I started pushing harder after break in I added even more air. I am 210 pounds vet rider, out for fun so I do not push this bike by any means. I run Inner Chamber 168 Outer Chamber 10 Balance 190. That is the sweet spot for me, now I just turn clickers to dial it in.

4. After installing the heavier rear spring and getting my sag right my rear suspension was a little stiff. I had chatter over breaking bumps especially on downhills with the front end loaded. I softened compression by a couple clicks and didnt even have to touch the rebound.

Hope this helps you out.
NJKawi913
Profile picture for user NJKawi913
Posts
265
Joined
6/5/2017
Location
Somerset, NJ, USA
NJKawi913 4/12/2019 7:16am
4/12/2019 7:16am
FFDan wrote:
My thoughts and opinions, and I am only pointing out a couple obvious things as I didnt see it in your original post. 1. Set your...
My thoughts and opinions, and I am only pointing out a couple obvious things as I didnt see it in your original post.

1. Set your sag first. At 190 and then adding your gear your rear spring is probably too light for you. I have a KX 450 and had to get a stiffer rear spring to get in the sag range. Race tech has a site that tells you the recommended rear spring for your weight and ability. Once your sag is right and the bike is balanced then you can move on to the air in front forks, clickers on the front, and clickers on the rear shock.

2. I realize I am in the minority, but I like the SFF air forks. It took bit to dial them in but I think they are great. I found most people get wrapped up in adjusting the air when what you should do is find the working spot then use the clickers on the left fork. One of my complaints is the checking air pressures every ride.

3. I found the air pressures are low from the factory. When I first started riding the bike at break in I thought the suspension was way to stiff. I dropped a little air to soften and it got worse. I did a little research and found the key issue was I wasnt running enough air. I was in mid stroke from not enough air. I added lots more air back in and it softened up nicely. Then as I started pushing harder after break in I added even more air. I am 210 pounds vet rider, out for fun so I do not push this bike by any means. I run Inner Chamber 168 Outer Chamber 10 Balance 190. That is the sweet spot for me, now I just turn clickers to dial it in.

4. After installing the heavier rear spring and getting my sag right my rear suspension was a little stiff. I had chatter over breaking bumps especially on downhills with the front end loaded. I softened compression by a couple clicks and didnt even have to touch the rebound.

Hope this helps you out.
This is a 250F, they use SFF spring forks, No Air. I also own a 15" KX450F and have spent countless hours tweaking those forks.

To follow up on the other points, I have the sag set at 103mm, and i do realize spring rates are off for my size, which i am going to address. I am just trying to tune a little bit on my own for my own knowlegde.
m21racing
Profile picture for user m21racing
Posts
649
Joined
7/19/2016
Location
Reno, NV, USA
m21racing 4/12/2019 7:27am
4/12/2019 7:27am
The shock spring is soft for you, but the fork spring may be close. I thought it was increased to 1.0kg. Set preload in normal range, and start at 10c 10r. If you use too much preload, you will get chatter under braking. You can slightly up your fluid levels, but not too much, as previously stated.
Titan777
Profile picture for user Titan777
Posts
329
Joined
12/1/2018
Location
USA
Titan777 4/12/2019 11:37am
4/12/2019 11:37am Edited Date/Time 4/12/2019 11:38am
m21racing wrote:
The shock spring is soft for you, but the fork spring may be close. I thought it was increased to 1.0kg. Set preload in normal range...
The shock spring is soft for you, but the fork spring may be close. I thought it was increased to 1.0kg. Set preload in normal range, and start at 10c 10r. If you use too much preload, you will get chatter under braking. You can slightly up your fluid levels, but not too much, as previously stated.
I'm 160 and my settings are:

Comp: 19 out.
Reb: 16 out.
Pre: 6 in.

Is this too much preload? I get really harsh vibrations in very small bumps similar to this photo:



My sag is 105
on a stand 63.5
static sag 59
m21racing
Profile picture for user m21racing
Posts
649
Joined
7/19/2016
Location
Reno, NV, USA
m21racing 4/12/2019 11:50am
4/12/2019 11:50am
m21racing wrote:
The shock spring is soft for you, but the fork spring may be close. I thought it was increased to 1.0kg. Set preload in normal range...
The shock spring is soft for you, but the fork spring may be close. I thought it was increased to 1.0kg. Set preload in normal range, and start at 10c 10r. If you use too much preload, you will get chatter under braking. You can slightly up your fluid levels, but not too much, as previously stated.
Titan777 wrote:
I'm 160 and my settings are: Comp: 19 out. Reb: 16 out. Pre: 6 in. Is this too much preload? I get really harsh vibrations in...
I'm 160 and my settings are:

Comp: 19 out.
Reb: 16 out.
Pre: 6 in.

Is this too much preload? I get really harsh vibrations in very small bumps similar to this photo:



My sag is 105
on a stand 63.5
static sag 59
Have you changed front fork spring for your weight? At 160 you could be .90kg if they available.

With proper spring/sag I'd try 10 in from all out on preload. 10c 14r 235cc spring side and 310cc main. The front rate jumped up in 2017 from tree offset change to a 1.0kg
Titan777
Profile picture for user Titan777
Posts
329
Joined
12/1/2018
Location
USA
Titan777 4/12/2019 12:26pm
4/12/2019 12:26pm
m21racing wrote:
Have you changed front fork spring for your weight? At 160 you could be .90kg if they available. With proper spring/sag I'd try 10 in from...
Have you changed front fork spring for your weight? At 160 you could be .90kg if they available.

With proper spring/sag I'd try 10 in from all out on preload. 10c 14r 235cc spring side and 310cc main. The front rate jumped up in 2017 from tree offset change to a 1.0kg
Thanks for your quick response.
I didn't change the spring. All suspensions are stock.

160 is without gear but I assume I'm around 175 with full gear and small hydration pack (1L).
My sag was with gear on.

So I should change preload to 10 instead of 6?
Would it help if I give you the measurements of the fork tube while on stand and on ground?
m21racing
Profile picture for user m21racing
Posts
649
Joined
7/19/2016
Location
Reno, NV, USA
m21racing 4/12/2019 12:47pm
4/12/2019 12:47pm
m21racing wrote:
Have you changed front fork spring for your weight? At 160 you could be .90kg if they available. With proper spring/sag I'd try 10 in from...
Have you changed front fork spring for your weight? At 160 you could be .90kg if they available.

With proper spring/sag I'd try 10 in from all out on preload. 10c 14r 235cc spring side and 310cc main. The front rate jumped up in 2017 from tree offset change to a 1.0kg
Titan777 wrote:
Thanks for your quick response. I didn't change the spring. All suspensions are stock. 160 is without gear but I assume I'm around 175 with full...
Thanks for your quick response.
I didn't change the spring. All suspensions are stock.

160 is without gear but I assume I'm around 175 with full gear and small hydration pack (1L).
My sag was with gear on.

So I should change preload to 10 instead of 6?
Would it help if I give you the measurements of the fork tube while on stand and on ground?
Leave the bike the way you have it, and put a zip tie or oring on non brake fork tube. Go ride the section which is giving you the harshness. Look at the position of the tie/ring on tube. Knowing the spring rate being too stiff, thats the main reason for the harshness. But, you can mess with preload in each direction to see what feels better or worse, and look at indicator change with the adjustments.
1
NJKawi913
Profile picture for user NJKawi913
Posts
265
Joined
6/5/2017
Location
Somerset, NJ, USA
NJKawi913 4/18/2019 8:54am
4/18/2019 8:54am
m21racing wrote:
The shock spring is soft for you, but the fork spring may be close. I thought it was increased to 1.0kg. Set preload in normal range...
The shock spring is soft for you, but the fork spring may be close. I thought it was increased to 1.0kg. Set preload in normal range, and start at 10c 10r. If you use too much preload, you will get chatter under braking. You can slightly up your fluid levels, but not too much, as previously stated.
so i went out yesteday and spun a ton of laps. I put the suspension back to the stock setting, went 10C 10R and it helped, but acceleration bumps are still brutal. I think some of it is being casued by poor body position when i fatigue, and compounded by the suspension
m21racing
Profile picture for user m21racing
Posts
649
Joined
7/19/2016
Location
Reno, NV, USA
m21racing 4/18/2019 9:01am
4/18/2019 9:01am
m21racing wrote:
The shock spring is soft for you, but the fork spring may be close. I thought it was increased to 1.0kg. Set preload in normal range...
The shock spring is soft for you, but the fork spring may be close. I thought it was increased to 1.0kg. Set preload in normal range, and start at 10c 10r. If you use too much preload, you will get chatter under braking. You can slightly up your fluid levels, but not too much, as previously stated.
NJKawi913 wrote:
so i went out yesteday and spun a ton of laps. I put the suspension back to the stock setting, went 10C 10R and it helped...
so i went out yesteday and spun a ton of laps. I put the suspension back to the stock setting, went 10C 10R and it helped, but acceleration bumps are still brutal. I think some of it is being casued by poor body position when i fatigue, and compounded by the suspension
You can now try and clear that up by going to 14r. See if that cleans up the issue a bit.
Titan777
Profile picture for user Titan777
Posts
329
Joined
12/1/2018
Location
USA
Titan777 4/18/2019 4:29pm
4/18/2019 4:29pm Edited Date/Time 4/18/2019 4:36pm
NJKawi913 wrote:
so i went out yesteday and spun a ton of laps. I put the suspension back to the stock setting, went 10C 10R and it helped...
so i went out yesteday and spun a ton of laps. I put the suspension back to the stock setting, went 10C 10R and it helped, but acceleration bumps are still brutal. I think some of it is being casued by poor body position when i fatigue, and compounded by the suspension
How much preload you run?

Post a reply to: SFF Tuning tips