What would be the difference(or benefit) between softening up the ICS spring or using less oil?

I've read of a couple of guys who have tried lowering the oil level with good result re: the slower stuff.

Jeff

What's the stock oil volume? Anyone know?

The whole point of the ICS is to keep the oil in the inner chamber pressurised to prevent cavitiation (bubbles forming that reduce damping efficiency). The KYBs don't run a preloaded ICS so they generally allow a little cavitation at the initial stroke anyway, but the further into the stroke you go the further the pressure increases.. however the increase is linear!

The oil volume acts as lubrication for the bushings and seals. The remaining volume of the fork (filled with air) then acts as a spring.. however the curve is not linear.

Usually oil volume has much less effect on initial stroke, and more to do with ramping up and bottoming resistance.

BUT! The whole system works together.. valving, springs, air gaps, etc.

Thanks, makes sense!

Jeff

Heres a visual..

https://www.youtube.com/watch?v=GBcRBOikb8c

I found a set of mx tech element 7 bladders and I now have the best set of KYB's I have ever ridden. If you can find them make sure to buy them.

I believe that I measured 350cc of oil in the outer chamber when I did my first oil change on my '18. I am running 320cc now and still have excellent bottoming resistance. I feel like the lower oil height made the forks a little plusher on the trail trash and smaller hits. The great thing about starting low with the oil height is that you can add oil through the bleeders in 5cc increments to dial it in.

I am 190 lbs, 200-205 geared up to race. I went to a 5.8 newton shock spring and went up either 1 or 2 increments stiffer in the front. They are Q springs that I got from JDP in Ohio and talked to him and these are what he suggested. Race and static sag are set perfectly with the shock spring rate he gave me. Don?t get me wrong the suspension on this bike is great I just find myself getting tossed around on whoops sometimes, maybe it is a fatigue and form issue on my part. Sometimes instead of the bike working to carry me through the whoops it will start going too far down in the stroke and get me out of rhythm, but I?m afraid if I go too far in adjustments it will be too harsh in the slow technical sections. Was just wondering if a revalve would actually show any improvement in both of these areas without too many adjustments. Maybe it?s just my issue and I should work on my skills some more.
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While we?re on the subject I have the motion pro air bleeders on my forks and they seem to get filled with oil and not bleed the air properly until I let the bike sit for a few days. I wonder if this is having a big effect on the feel of the forks?

I have never used the quick bleeders, but I have noticed that the forks can build up pressure and it does decrease performance.

315ml is what I used to run on my previous setup. I wasn't banging woops though either... nor am I what you'd call fast.

What I would suggest.. is that you contact a tuner and see if they are willing to work with you. I don't personally see any value in them just slamming their favourite stacks into your forks and hoping you love it.

It could be as simple as your rebound being too slow.. it could be the high speed compression needs to be firmed up. Given your weight and your spring rates I don't think it's a lack of spring.. BUT a decent tuner should be able to put you through a set of whoops and see what is happening, make some changes, etc. They really need to know the specifics of what is happening to be able to make informed decisions on how to resolve it.

I used to run 320ml in the TM?s Kybs with slightly stiffer springs, 350 works well for me now with springs that are a rate too soft.

Hate to start a new thread for this question -

If you remove the KYB fork Base/Compression Valve (say, to play with shims & valving) do you need to bleed the cartridge when you put it back?

Or can you just remove handlebars, unscrew Compression Valve, and just screw it back in when done making adjustments?

Jeff

Similarly, when I remove the cartridge to replace fork springs, does it need to be bled before replacing?