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I have a commencal meta v4 with a RS monarch piggyback shock. I'm 6'4" and weigh about 100kgs and i like to ride welsh mountains and south downs trails.
To get 30% sag i need 300psi in the shock and this damn near pocks a hole in my palm getting the last 50psi in.
I have put bottomless tokens in the front fork to good effect and thought i'd try the same on the shock. Ordered the requisite rubber bands and installed 3. Reassembled the shock in the frame, pumped it up hurting my palms and the result is that there is a discernible notch in the travel at about 20%. I spoke to TF tuned who said it's a blockage in the transfer port.
To cut it short, i have removed the shock and the air can about 5 times now and established that i may have inadvertently covered the top hole by putting the bands a tteh top of the shock not the bottom. But even after correcting this i still have the notch in the travel, albeit less so. I have carefully pocked the bands back down using a piece of plastic to ensure they aren't riding up on install and I've reduced it to two bands because there is a rib on shock body that the third band fouls on. the bands are surprisngly loose on the shock body, could they be being blown about when the shock cycles for the first time?
Does anyone know what might be causing the notchy feel? I will try reverting to zero bands to see if that cures it but as the 300 PSI gets seriously difficult to achieve each time i thought i'd ask before hurting my pal again. And yes I've been testing it at a more reasonable 150psi but the notch is still there.
thanks
john
Have you used the shock much? My first one developed a notch in the travel about the same position but a seal kit and air can service sorted it, dead simples to do at home. I don't think the seals last as long as Fox ones do, it wasn't even 50 hours before it started happening.
300psi sounds bonkers though. Are you cycling the shock as you inflate it to allow the air to move into the -ve chamber and equalise pressure? eg stop at 100 and cycle the shock a few times, and so on. And have you definitely put the bands in the +ve section of the can and not the -ve?
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I was surprised how much pressure my Monarch needed, 250ish IIRC - and I'm 75kg-ish.
It says its rated up to 320psi on the can.
Jim
thanks for your quick response.
i tried cycling the shock at 100, 150, 200 and still ended up at 300 to give me 25% sag and the notchy behaviour is still there. It does sound a ridiculous pressure, nearly twice what i used on my old trek fuel.
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I can't understand what has happened to cause the notchy motion. it must be something I've done or effected buy installing the bands. I'd be surprised if the seals have gone at the same time as my tinkering the coincidence seems too great. Any thoughts as to what could have been disturbed?
thx
I did damage the middle o-ring on the air can when I fitted the red bands, I think when I slipped the sleeve back on it got caught and put a little crease in it. This was enough to make the shock slowly collapse as the air moved freely between +ve and -ve chambers, but isn't the same as your symptoms.
The notch feel though was cured by fitting new seals. If you've not used it then it could be a warranty job though beware Fishers can take months to get a replacement to you.
Thanks, i will check the o ring to see if I've damaged it. i tried sitting on the bike slowly to be a bit more specific about what is happening and the best way i can describe it is as per this graph [img] 
[/img] the first part of the travel the shock compresses smoothly but there is a distinct sound in the shock, then the pressure suddenly reduces, as if something has moved or relaxed. The shock then sinks further into its stroke until the pressure builds up. it doesn't collapse, more relaxes a bit and in the second phase of the travel it sounds quieter too. If i tak the weight off at any point the shock extends back fully so it doesn't appear to be losing pressure, something feels like its giving.
it's 6 months old and been to the alps and wales so had more than 200 hours on it. Definitely out of warranty i think and it came direct from Commencal in Andorra.
The pressure balances at 20% so its normal to feel a notch at that point. However it should go away and certainly should not be an issue each stroke. It sounds to me like you are loosing air from the + into the -ive as you compress, which pumps up the negative only to balance again at 20%. This is probably down to damaging the seal that sits between the chambers. As mentioned, take of the band, check its ok, clean it up, clean beneath it and put it back on with plenty of grease. That may fix it for you.
Ben,
thanks for the advise, i will check the 'o' ring very carefully.
Cheers John
it's 6 months old and been to the alps and wales so had more than 200 hours on it
😯 you 'should' have replaced the seals twice by now if you haven't already, and probably had at least one full service too. I had the notch come in way before your number of hours and replacing the seals worked a treat. They're only about £15 too.
So I've replaced the seals, very straightforward but there is still a slight transition in the stroke. for now i'm gonna enjoy it and service these puppies more regularly. the amount of dirt inside the shock body was surprising, at least to me. So as Bigjim said it should have been looked at much more frequently. lesson learned. thanks