Hi, I have searched but have found very little info.......so.....who has one and what's the verdict please?
Sent from my CLT-L09 using Tapatalk
Sent from my CLT-L09 using Tapatalk
Fast Yari up damper
lawson
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How linear is the rebound damping curve being able to (externally) adjust only lsr?
The grip2 is pretty linear, maybe that’s what I’m feeling mostly.
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Sorry, but I can't really tell you that. However, considering it's so easy to change the shim stack, just throw several more shims on there and see how it feels.
I was told by Fabien that the lack of orange foams in the v1 makes the system not be pressure balanced. This results in a gap in time with “no damping” and cavitation. And that that’s likely what I’m experiencing.
My local dealer has no interest in getting the foam kit (yay!). I guess my question is: is that a cheap way to secure 20€ a year or is that trully the root cause to the problem I’m experiencing..?
My local dealer has no interest in getting the foam kit (yay!). I guess my question is: is that a cheap way to secure 20€ a year or is that trully the root cause to the problem I’m experiencing..?
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Up front, I'm definitely NOT a suspension engineer.
If this is regarding rebound issue mentioned before, then no, I don't think it's the cause of the root problem. If cavitation were occurring on rebound, it would be on the low pressure side of the rebound piston, and would noticeable as a momentary lack of compression damping as the fork transitioned from rebound to compression. Having cavitation on compression could cause a momentary lack of rebound as it transitions from compression to rebound, but the amount of oil passing through the compression piston is relatively small since it's only the oil being displaced by the rebound rod.
Instead, what I think you're feeling is a HSR shim stack that's too stiff. With the LSR fairly open there isn't enough pressure generated to open the shims so rebound deep in the stroke is too slow. Once you close LSR it creates enough pressure on the shims to open them and allow the rebound to be fast enough deep in the stroke.
I would pull the rebound rod and piston out, remove a shim (or two), and see how it feels.
The rebound has two shims and they’re 0.1mm thick, so there isn’t much room to play with… I’ll see what I can do
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Try taking one out and see how the fork reacts. If it swings too far in the direction you want, then buy try something inbetween. If it's become even worse, then call me an idiot and slap an extra shim on there to stiffen it up more.
Ultimately though, I think you'll get to where you want by adjusting the HSR shim stack.
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1,368 Posts
Can you order the foam kit directly from
Fast? I ordered the whole kit, damper and foam, directly from them.
Out of stock though:
FAST Foam kit UP Performance
Boost your UP kit's performance with this closed cell foam Cartridge 100% closed, more stability, no emulsion and more endurance. Kit composed of 3 foams, V1 and V2 compatible
s4suspension.com
I wonder if foam pipe insulation the same ID and OD would work
My bad, upon reviewing the hsr stack it’s got a cross over shim (not just 2 shims):
piston
23x0.1
crossover (haven’t measured it)
19x0.1
piston nut
But I think you might be on to something here. In the past I’ve ridden this damper blown, had the 23 and 19 mm shims partially broken and the rebound felt better 😂
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I just looked it up, and the Yari uses Rapid Recovery Rebound, so that cross over is most likely a preloaded ring shim instead. Preloaded rebound feels like ass, so I'd remove that and see how it works for you.
It’s not a ring shim, I’m almost positive you can’t preload that piston side without a ring shim too.
Removing the cross over shim will stiffen the hsr stack instead.
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Received my Up kit today, along with some tchotchkes, which is always nice. The team at Fast have been great to deal with so far, especially since I was able to buy directly through them at nearly half of what it would’ve cost from their North American dealer. Just waiting on some 0W-30 oil and a bleed kit so I can do the install.
I‘ll make sure to update with some first impressions.
![Image]()
I‘ll make sure to update with some first impressions.
What are your first impressions after some rides?
Do the foam convert the emulsion style damper to a close cartridge one?
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Got distracted for the past few weeks. Planning to install it today or tomorrow. I will let you know.
Edit: Installed today. Took about ninety minutes, mostly because I’m barely competent with tools. Bled the system per instructions I found elsewhere - the Fast installation video on Youtube is in French and the autogenerated subtitles are useless bordering on comical. Plan to ride in the next couple of days with both compression dials set in the middle - each one has 30 clicks. Will report back with early impressions.
Does anyone know if replacing the foam compensators in the yariup annually is truly necessary-given that they’re kind of hard to get a hold of in the U.S.? I mean, they only way they’d stop working is if they either become stiff and harder to compress/rebound over time, or they degrade so the closed cells become open and release their air/absorb oil, right? Do those things happen?
They sure seem like sections of a pool noodle…
edit...s4 doesnt carry them anymore and it looks like Fast wont ship directly to US so I guess ill just hope the foam doesnt break down. Sigh
They sure seem like sections of a pool noodle…
edit...s4 doesnt carry them anymore and it looks like Fast wont ship directly to US so I guess ill just hope the foam doesnt break down. Sigh
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I’ve been running mine for two seasons without issue. I checked the foam when I did a lower leg service and it seems fine.
same here. Curiuos, what are your thoughts on it, and your settings?
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Or just get rid of it entirely.
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