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Edited Date/Time
8/16/2018 9:48am
These caught my eye. Curious if anyone has experience yet using these as a drop in replacement? Only $60. I know the plastic pistons are prone to breaking. They offer a standard replacement, as well as a LT version...
FREE PISTON for KYB AOS (Twin chamber) front forks.
ZE56-40012 LT Light weight and less friction design, provides soften and smooth front fork moving.
http://www.zeta-racing.com/sus/freepiston/index.html
https://youtu.be/-MnrOym34us?rel=0
FREE PISTON for KYB AOS (Twin chamber) front forks.
ZE56-40012 LT Light weight and less friction design, provides soften and smooth front fork moving.
http://www.zeta-racing.com/sus/freepiston/index.html
https://youtu.be/-MnrOym34us?rel=0
I suggest the "plush" version or whatever they call it not because of that... rather because kyb screwed up and didn't allow the upper chamber of ics to be equalized to atmosphere stock. Showas clone of the sss found on the Crf250r 2010 had this bleed screw (FYI)
The Shop
I've seen plenty stil break. It's an enigma but they still do it.
I'll be going for the solid ones with both O-rings.
It's hard to believe that KYB would leave the pistons solid without the relief holes for 12 years, if having the piston solid wasn't for a reason. I'd really like to know that reason.
They have to be aware of the pistons exploding. Is the free piston the cheap part that prevents more expensive damage?
Is it solid for performance reasons?
What do they recommend? Holes or no holes, solid or open? 0-rings or no o-rings?
If anyone has a contact from KYB engineering that can answer these questions it would make it a lot easier to choose a free piston replacement.
And of lesser importance:
Why are the pistons open on some bikes, but solid on SSS? Is the solid piston a part of what makes SSS great?
There was a thread on this a while back with some suspension guys including ML chiming in.
I appreciate the feedback, and that drilling the holes mostly prevents the pistons from exploding, but it would be great to know from KYB what they recommend on the question above and why.
Have a great day!
Radical
Most people can NOT tell a difference from a drilled set to an std set.
The SSS was sold on a host of bikes - Thank MXA for mis marketing it as exclusive to yamaha. Honda 450 in 09-last year before air fork had them
kawasaki 450 had them through 2012 i think starting in 06 but certainly in 09 was identical design as yamaha had.
I see a lot of enzo forks with the ICS pistons drilled....take it for what you want - they work closely with kyb
KYB really screwed up by NOT allowing a bleed hole for the ICS air space that is sealed in the piston. If pressure does somehow build up whether its temperature rise - or leakage of pressure from outer chamber etc...it can not be bled. Also - if you take a non drilled SSS fork from sea level to altitude - the pressure in the ICS chamber will be much higher than intended.
Showa's first clone of the SSS that came on the 10 crf250 (and I do mean clone - through and through) had two bleed screws. One for the outer chamber - one for the ICS chamber. As they adopted a "drilled" style design this went away. The bleed screw is a smart and IMHO necessary addition to a sealed ics chamber.
Ultimately many people (including a host of shops) do not understand what the ICS springs influence actually is on a fork - or what varied pressure/spring rate will have on it. The difference in pressure on the top side of the ICS chamber when it's drilled and not drilled is not drastically different except when close to bottomed. The first 2/3 of the stroke drilled vs non drilled is nearly identical.
Get them from Langston's Motorsports.
So, it makes sense that bottoming may be slightly harsher with the open piston and missing top o-ring, but not really (or so slight that it doesn't matter) with the bleed holes drilled in the plastic piston.
With the open piston or with holes drilled, does fork oil make it's way where it normally wouldn't?
It could be many things, but I did notice a difference with my forks after the broken plastic piston was replaced with an open one, and the other plastic piston drilled. I can't really say what's different, just that it's not better.
I think suspension will be the next thing for me to really learn about.
It's difficult to ride and know what to change.
It's going to take some time.
Thanks again
I also have small spacers installed between the spring and base that removes the slop from the piston allowing for easier bleeding of the IC and it seems to work well for the past few years. Has anyone else done this modification and what have your results been?
My theory is oil trapped above the piston lessens the air volume for the piston displacement and when the fork takes a big bottom, there is a greater air pressure rise above the piston than the plastic piston can handle and the air bleed can release. It could be cyclic failure or it could be a sudden failure I don't know.
Just my 2 cents.
Pit Row
They do indeed give a plusher small bump ride. The a-kit kyb's have more bottoming control than the stock kyb's so I can't comment on how they would work on a stock kyb fork, but I don't see how they can be more plush and have more bottoming resistance at the same time... They are great for off road but I don't use them for MX. I switch back to the solid free piston.
ZETA recommends adding 70cc of oil to compensate for the added volume, but the initial plushness goes away and you gain a lot in bottoming resistance. Better for MOTO.
I actually wanted to replace them with aftermarket ones on the 10 model after reading about oem broken ones & FC suggested I didn't need them. They drilled the holes on the plastic oem's & saved me a few $'s in the process.
I’m not sure if it’s the o-ring on the piston or the shaft seal but either way they both failed.
Post a reply to: Has Anyone Tried These ZETA KYB AOS Pistons Yet?