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Showa SFF TAC Oil Heights

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Hey,

 

  are the showa sff tac air fork ( the air fork leg) oil heights adjustable?

 I drained 25-30ml from my 16' kxf450 balance chamber but the manual calls for just 5ml of oil?

 Also, I have gone up 50ml oil in the damper leg to control bottoming, is it better to add oil to the damper leg or air leg or split it 50/50 ?

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God damn. 50ml? How did that work out for you? I found that 5cc was good enough for. Me

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5 hours ago, Dexter-41 said:

Hey,

 

  are the showa sff tac air fork ( the air fork leg) oil heights adjustable?

 I drained 25-30ml from my 16' kxf450 balance chamber but the manual calls for just 5ml of oil?

 Also, I have gone up 50ml oil in the damper leg to control bottoming, is it better to add oil to the damper leg or air leg or split it 50/50 ?

I was curious since I have a 2015 crf250r with Showa SFF TAC forks. From what I can tell they are basically the same. Top cap on the damper is a little different and my balance chamber is internal to the fork and takes no oil (in fact I have to bleed that dry). Other than that they seem to have the same internals and operate the same.

That being said, I looked at your owners manual. The outer tube on damper side can vary the oil to control bottoming. It ranges from 300 ∼ 398 mL (10.1 ∼ 13.5 US oz.) with STD being 340 mL (11.5 US oz.). The tuning section says: "Changing the fork oil amount works effectively at the end of fork travel. If fork bottoming is experienced, raise the fork oil amount by 5 mL (0.2 US oz.) each". Mine is the same, only the one oil level is adjustable. 

When I was trying to fix my 250 from bottoming I tried a small increase from STD and it did not do much. I then tried MAX but it ended up not using the last inch of travel and felt a little harsh. I ended up at 10mL less than max because that was where I used all the travel and didn't bottom harshly. I tie a rubber band (actually two looped together to get a longer length) tied around the fork tube so that I can see how much travel I'm using.

I liked lower than std on the air settings to get the forks to move more at the top to mid stroke giving me a more plush feeling; otherwise the air forks were just beating me to death and cornering was absolutely crap. In addition, the tracks I ride are ripped deep and watered heavily hence get whooped out quickly. So I was looking to get the forks to follow better in such conditions. The lower air pressure combined with my weight and track conditions are the reasons I think I needed oil to be more towards max.

It was a long process for me to figure out the right settings for me on the SFF TAC forks. 

 

According to the manual for your bike,

Inner: Std = 1 000 kPa (10.20 kgf/cm², 145psi), range = 600 ∼ 1 300 kPa (6.11 ∼ 13.26 kgf/cm², 87.0 ∼ 188.5 psi)

Balance = 900 kPa (9.18 kgf/cm², 131 psi); range = 530 ∼ 1 400 kPa (5.40 ∼ 14.28 kgf/cm², 76.9 ∼ 203 psi)

Outer: Std = 50 kPa (0.51 kgf/cm², 7.3 psi); range = 0 ∼ 130 kPa (0 ∼ 1.33 kgf/cm², 0 ∼ 18.9 psi)

Edited by GoneDirtBikeN
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I re-read your post and see that you said you drained 25-30ml from the outer. That is because some will bleed from either the inner or outer chambers (I think it is the inner) into the balance. Although 30mL is a bunch. Either you haven't serviced your forks in quite a while or you need to check/replace the o-rings that separate the chambers. I found that changing the o-rings help reduce that bleeding into the balance chamber quite a bit.

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Hey,

 

 Im heavy at 260 lbs , had my suspension revalved but forks were running to low in the stroke, and bottomed so i decided to add oil instead of going with higher inner pressure as i'm at 200 inner & 180 balance.

 

 I have increaed the damper leg oil height gradualy and it has gotten better and better with more oil.

 

I had a weaping fork seal on the air leg so cleaned  out the seal and changed the oil in all 3 chambers, but i noticed 25ml ish come out of the balance chamber that was black, my bike has now done 13 hours from new, i was a bit confused when 25ml drained from the balance chamber when the manual says to add just 5ml.

 

 I wondered if the oil heights were set in stone or are tunable for the air side fork leg

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I edited my prior post and listed the std and ranges of the air pressure. The pressure you are using on the inner is above max. I would reset that to no more than what the manufacturer lists.

It helps to understand what the different air pressure settings do. The inner acts as your spring rate. Pretty easy to understand that. Higher air = heavier spring rate. The balance controls the initial movement so if you have balance higher than inner, the initial movement will be softer. If you have balance lower than inner, the initial movement will be harder. My bike is different but I set balance 2 lbs higher than inner because with the TACs they are rather stiff on initial movement. In Sand when I want the forks to resist diving a bit more, I set balance = inner. That is pretty much the only time I vary the air settings.

The outer chamber is used to adjust the bottom of the stroke. You can use it to help with the bottoming. I suggest you experiment by adding 1-2 lbs at a time starting from std but not more than the recommended max.

Yes, the oil that comes out of the balance chamber is really black. The first time is the worst because of the break-in but even after any oil coming out of the balance is black. As I mention prior, mine calls for no oil but to bleed. What I bleed out is sinfully black and would certainly contaminate any small amount of oil that your's calls for. IMO the oils in the TAC forks need serviced fairly often. I've been doing mine at 20 hours or less and that may even be pushing it.

Showa has an app. I suggest you download it to your phone and play with the settings. You will see how air in the outer chamber can be use to control bottoming. If you increase the outer to control bottoming, you may want to increase the balance to soften up the initial part of the stroke. Then again at your weight maybe having the whole stroke stiffer would be good. Playing with the app you can see what affect it would have before you test on the bike to see if you like it.

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