Are you talking about your DHX or 5th? What are all your clicker settings? Is that your only complaint, does it get worse or better under braking?
anyone familiar with 5th elements??
- Thread starter dhkid
- Start date
thats my dhx, 5th is dead for the time being.
propedal was about 5 clicks from full open, chamber size 2.5 lines, pressure 100psi. rebound all the way out.
cant really say how it really went under braking, maybe a bit worse if at all? i didn't jump on the brakes coz it was quite a steep section that you dont want to mess up on. but generally under braking over bumps my suspension does stiffen up, is there something going on there, coz i just accept that that will happen.
i really need to go back there and try different settings, thats the main problem i have with tuning my suspension right now. have time to go out and focus on tuning it, that and i dont have excess to a work shop to fix my suspension.
propedal was about 5 clicks from full open, chamber size 2.5 lines, pressure 100psi. rebound all the way out.
cant really say how it really went under braking, maybe a bit worse if at all? i didn't jump on the brakes coz it was quite a steep section that you dont want to mess up on. but generally under braking over bumps my suspension does stiffen up, is there something going on there, coz i just accept that that will happen.
i really need to go back there and try different settings, thats the main problem i have with tuning my suspension right now. have time to go out and focus on tuning it, that and i dont have excess to a work shop to fix my suspension.
Hmm..generally if it's worse under braking it's more LSC is needed. It could be squatting too much under braking, I'm not really up on the mechanical characteristics of many frames so I can't comment on the squat characteristics of your bike but if it's harsh under braking you probably could make it better with more LSC. I assume you have tried many external settings but 100psi seems a little high for a low levered bike(my DHX tuning is fairly limited) could you maybe lower the pressure a touch and increase ProPedal?
If it's harsh off the brakes and across the tops of bumps it's generally LSR. Seeing your adjuster all the way out might be a clue, and after the exhaustive post on rebound speed i think we can all agree at least that leverage ratio plays a factor in the needed damping force. Your low levered bike may need a slightly lighter reb. stack.
Funny thing is, harshness is rarely too much high speed (at least with a "properly-ish" set up bike).
My advice with internal tuning, try ONE small change at a time. Take a bunch of small steps in a positive direction as opposed to a large step in a direction and a large step back b/c it wasn't right.
If it's harsh off the brakes and across the tops of bumps it's generally LSR. Seeing your adjuster all the way out might be a clue, and after the exhaustive post on rebound speed i think we can all agree at least that leverage ratio plays a factor in the needed damping force. Your low levered bike may need a slightly lighter reb. stack.
Funny thing is, harshness is rarely too much high speed (at least with a "properly-ish" set up bike).
My advice with internal tuning, try ONE small change at a time. Take a bunch of small steps in a positive direction as opposed to a large step in a direction and a large step back b/c it wasn't right.
hmm, everything seems to go back to lsc.
this got me thinking, if i am only 125lbs, and i am already using loads of LSC, and having much faster rebound then alot of people out there. how would other people go through a section like that.
i was riding with a couple of other guys and they didn't have that sort of trouble, they were able to stay pinned the whole way down. and i know they dont run loads of lsc or fast rebound.
could it be that i am running too much lsc?
do you still think that my previous idea of reducing the HSC on the shim stack and using more of the boost valve for that would still be a good idea?
i know it should really come down to going out and finding out, but i would like to know as much as i can before i go nuts, so i would have a rough idea of what i want to achieve and how to achieve it. i only got a short window of 3 weeks of riding/tuning when i get back home.
this got me thinking, if i am only 125lbs, and i am already using loads of LSC, and having much faster rebound then alot of people out there. how would other people go through a section like that.
i was riding with a couple of other guys and they didn't have that sort of trouble, they were able to stay pinned the whole way down. and i know they dont run loads of lsc or fast rebound.
could it be that i am running too much lsc?
do you still think that my previous idea of reducing the HSC on the shim stack and using more of the boost valve for that would still be a good idea?
i know it should really come down to going out and finding out, but i would like to know as much as i can before i go nuts, so i would have a rough idea of what i want to achieve and how to achieve it. i only got a short window of 3 weeks of riding/tuning when i get back home.
It could be, of course there are a large number of possibilities of what it could be. Your friends could have a setting where they don't have a spike and can plow through rough straight sections off the brakes but they may have a tough time controlling their bike in corners or under braking? Or it could be perception, both bikes might be working the same and they are loving it b/c it's the best thing they've ridden and they aren't paying attention and your hating it b/c your reading all these threads about how good it can be and your focussed on it. I know I've been in love with my bike then made a setting change and gone..."Wow, I don't know how I rode that old POS setting for as long as I did!!"
It could also be that you think your running lots of LS but in reality your increase to LS also increased the mid to HSC too? Just a thought.
*Disclaimer, before I continue* My following statements are not to be taken as criticism toward any product that you may be currently in a loving relationship with, merely observations I've made that are intended to help someone who is asking questions about and interested in fine tuning.
It's hard to externally tune lots of LSC into the DHX without getting an increase in HSC too.
#1 you have the huge bleed threw the main piston bolt. That takes away a percentage of dampening more noticeable on LS.
-Also, the external adjustments meter ONLY the oil displaced by the shaft, again a smaller percentage of the total damping.
-Finally, the Pro Pedal and Boost Valve control the same orifice so it's difficult to separate a high and low speed
when you say it hard to tune LSC without getting an increase in HSC, are you referring to contribution from the boost valve?
hopefully i get the results i want when i close off the rebound bleed, sounds like i would have to remove alot of the hsc on the main piston to get where i want. maybe not even increase the lsc on the main piston that much since i am running the rebound bleed fully open now.
Right, ProPedal and the BoostValve both control oil flow through the same orifice. The Boost Valve Volume controls the "ramping." The Boost Valve air pressure increases or decreases the entire damping range and the ProPedal fine tunes the entire range, though it's affects are mostly felt initially (think about the results of adding a linear coil spring curve to an exponential air spring curve.)
I agree with your idea of trying to shut down the compression bleed but it will be VERY difficult to achieve the proper rebound with shim stack changes only, not saying it can't be done. I would try to find a small ball bearing and screw to make a ball check. The DHX piston bolt already has threads inside.
ahh, i get what you mean with the piston bolt. i didn't realize that everything was in place for it already, i was looking at the bolt in front of me and suddenly a dim light bulb turned on. lol.
i will still try to have a go at shutting down the rebound bleed. (sorry, i am stubborn like that, just for the sake of trying.) looking at the rebound shim stack on the dhx i dont have much tuning options tho. there are only 5 shims on the stack. this time i do have a second set of dhx shims thanks to davep, so that helps with the options. i might try running lighter oil weights again, but i got a feeling that i am going to mess things up so amazingly well.
getting back to the whole 5th element, i understand that the control valve will provide more damping as it gets deeper into its travel. through some back of the envelop type calculations i came to a conclusion that the control valve 'opens up' with out alot of resistance , ie on high shaft velocities. making the assumption that at that instant of time, oil is flowing through the cv, but the
what actually will provide the damping needed is the increase of damping deeper into its travel. is that roughly correct?
is that sorta a way to look at the different ways a pyramid shim stack work against the control valve? this brings me to how a shox like the roco can work when its purely speed sensitive and has no position sensitivity to it at all.
do you reckon the idea of letting the main shim stack handle the LSC and the boost valve handle the HSC and the ramping up still a good idea?
how i wish i had a dyno to have actual data i can look at then this armchair guessing game.
i will still try to have a go at shutting down the rebound bleed. (sorry, i am stubborn like that, just for the sake of trying.) looking at the rebound shim stack on the dhx i dont have much tuning options tho. there are only 5 shims on the stack. this time i do have a second set of dhx shims thanks to davep, so that helps with the options. i might try running lighter oil weights again, but i got a feeling that i am going to mess things up so amazingly well.
getting back to the whole 5th element, i understand that the control valve will provide more damping as it gets deeper into its travel. through some back of the envelop type calculations i came to a conclusion that the control valve 'opens up' with out alot of resistance , ie on high shaft velocities. making the assumption that at that instant of time, oil is flowing through the cv, but the
what actually will provide the damping needed is the increase of damping deeper into its travel. is that roughly correct?
is that sorta a way to look at the different ways a pyramid shim stack work against the control valve? this brings me to how a shox like the roco can work when its purely speed sensitive and has no position sensitivity to it at all.
do you reckon the idea of letting the main shim stack handle the LSC and the boost valve handle the HSC and the ramping up still a good idea?
how i wish i had a dyno to have actual data i can look at then this armchair guessing game.
Keep me posted with the rebound tune and how it goes, I'm curious. I'm not 100% sure the ball and bolt will work but I suspect you can make something.
As far as the 5th vs the DHX vs the Rocco...I'll try to give a snapshot opinion as it's a very complex scenario, and yes, a dyno or even a dyno graph would help immensely. A control valve generates curves on a position vs force graph. A pyramid stack generates curves on a velocity vs force graph. On a position vs force graph, shims, no matter their configuration, draw a straight line. So for a given velocity, no matter where the shaft is in the travel, the force will be the same. As you pointed out, one of the features of the CV is the ability to provide a bump blow off. A high speed hit will generate a quick internal rise in pressure on the piston face which will pop the CV open, as soon as that pressure starts to equal out on the other side of the piston, the CV starts to shut down. Basically the CV is always fighting bump force pressure that wants to open it and internal pressure, which wants to keep it closed. As I'm sure you aware that internal pressure that wants to keep it closed increases as the damper compresses. It looks like your question got cut off but I'm thinking it had to do with the CV popping open easy and what keeps it from bottoming. Yes, the rise in pressure due to displacement will increase damping but I feel that sometimes the CV "hangs" open a split second too long and the build of damping at the end isn't enough to stop it. With the help of a good compression adjuster though it balances out.
As far as the Roco being "only" speed sensitive, moto dampers are only speed sensitive too. In this scenario position sensitivity comes from the links, providing less and less leverage force as the damper compresses. The heat that moto dampers generate rule them out for candidates for pneumatic valves, for now. Heat=pressure=damping!!
Also, by manipulating the shim stacks you can come up with some very good settings. Generally a digressive type curve (velocity vs force) combined with a leverage modifying link provides the best set up.
Did that help?
As far as the 5th vs the DHX vs the Rocco...I'll try to give a snapshot opinion as it's a very complex scenario, and yes, a dyno or even a dyno graph would help immensely. A control valve generates curves on a position vs force graph. A pyramid stack generates curves on a velocity vs force graph. On a position vs force graph, shims, no matter their configuration, draw a straight line. So for a given velocity, no matter where the shaft is in the travel, the force will be the same. As you pointed out, one of the features of the CV is the ability to provide a bump blow off. A high speed hit will generate a quick internal rise in pressure on the piston face which will pop the CV open, as soon as that pressure starts to equal out on the other side of the piston, the CV starts to shut down. Basically the CV is always fighting bump force pressure that wants to open it and internal pressure, which wants to keep it closed. As I'm sure you aware that internal pressure that wants to keep it closed increases as the damper compresses. It looks like your question got cut off but I'm thinking it had to do with the CV popping open easy and what keeps it from bottoming. Yes, the rise in pressure due to displacement will increase damping but I feel that sometimes the CV "hangs" open a split second too long and the build of damping at the end isn't enough to stop it. With the help of a good compression adjuster though it balances out.
As far as the Roco being "only" speed sensitive, moto dampers are only speed sensitive too. In this scenario position sensitivity comes from the links, providing less and less leverage force as the damper compresses. The heat that moto dampers generate rule them out for candidates for pneumatic valves, for now. Heat=pressure=damping!!
Also, by manipulating the shim stacks you can come up with some very good settings. Generally a digressive type curve (velocity vs force) combined with a leverage modifying link provides the best set up.
Did that help?
yea, that helped alot. especially the part on how moto bikes get around the problem of progression. that would mean that a damper like the roco wouldn't be ideal for a bike with a linear or falling rate would it?
i'll post back in a couple of weeks once i have worked on my shox.
i'll post back in a couple of weeks once i have worked on my shox.
Can someone give me the IFP depth for 8.5x2.5 size 5th? I"m shortening my shock from 8.75x2.75.
this looks really sick
.....
http://avalanchedownhillracing.com/5th%20element%20speed%20sensitive%20conversion.htm
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http://avalanchedownhillracing.com/5th%20element%20speed%20sensitive%20conversion.htm
Excellent info guys, especially Mtty Tee! I wish I had seen this thread before I rebuilt my 5th. I always thought the 5th was a really nice shock when set up properly. Because of that I stocked up when they went out of production. I own five of them.
The one I rebuilt I pulled mostly apart except for what appeared to be a valve down at the bottom of the IFP chamber. I've got another one apart right now off an older Bullit that's probably 2002 vintage and it doesn't appear to have that part in it. I wish I still had the other one apart to make sure I wasn't just hallucinating.
On the one I rebuilt, the bushing in the end cap was disintegrating. It fed bits into the main seal causing it to leak. I pounded it out and found it was marked 08IB08 and looked to be the same type as the steel backed bronze alloy DUs I use in the eyelets so I pressed one of those in.
I cleaned everything up, but used the existing seals. I filled it with 5 weight oil and tried it out. Super smooth! I am going to order some of the lower durometer seals and swap it out when I get a chance though. That sounds like a nice performance mod.
Mtty Tee, do you know the part# for the CV seals, IFP seal, and that seal on the rebound needle? I figure if I'm ordering seals I might want to get some spares for those as well. I'm also wondering if there's any place to buy spare dust wipers? I don't remember seeing those anywhere.
Also, do you know the stock oil? Maybe the cSt numbers? Oil weight is kind of meaningless because of the variation brand to brand.
BTW, I don't have access to an air compressor so I had to improvise to get the IFP out. I pulled the LSR shims off and I used the rebound needle to control oil flow to push it out. I'd push the needle all the way down during compression to block off the oil flow and push the IFP. Then I'd pull the needle before rebounding the main piston. Without the shims there was free flow. After about 3 cycles the IFP was at the top and I could pull it out with a pick.
The one I rebuilt I pulled mostly apart except for what appeared to be a valve down at the bottom of the IFP chamber. I've got another one apart right now off an older Bullit that's probably 2002 vintage and it doesn't appear to have that part in it. I wish I still had the other one apart to make sure I wasn't just hallucinating.
On the one I rebuilt, the bushing in the end cap was disintegrating. It fed bits into the main seal causing it to leak. I pounded it out and found it was marked 08IB08 and looked to be the same type as the steel backed bronze alloy DUs I use in the eyelets so I pressed one of those in.
I cleaned everything up, but used the existing seals. I filled it with 5 weight oil and tried it out. Super smooth! I am going to order some of the lower durometer seals and swap it out when I get a chance though. That sounds like a nice performance mod.
Mtty Tee, do you know the part# for the CV seals, IFP seal, and that seal on the rebound needle? I figure if I'm ordering seals I might want to get some spares for those as well. I'm also wondering if there's any place to buy spare dust wipers? I don't remember seeing those anywhere.
Also, do you know the stock oil? Maybe the cSt numbers? Oil weight is kind of meaningless because of the variation brand to brand.
BTW, I don't have access to an air compressor so I had to improvise to get the IFP out. I pulled the LSR shims off and I used the rebound needle to control oil flow to push it out. I'd push the needle all the way down during compression to block off the oil flow and push the IFP. Then I'd pull the needle before rebounding the main piston. Without the shims there was free flow. After about 3 cycles the IFP was at the top and I could pull it out with a pick.
Thanks dhkid!
Here's a partial list of oils from PVD's website and notes of which have been tried in the 5th. I may give the Silkolene Pro RSF 2.5w a try myself when I swap the main seal. That oil would have a cSt of 16 at 21C (70F).
I wonder if the the stuck CV problem is aggrevated more by thinner oil, or high pressures? I tend to run around 60 psi with a pretty open volume adjust. I know the CV problem is 'fairly' common, but I've never had it happen to me.
where'd you find that chart with the oils broken down like that?!
Danno, for the late reply. Here is a link to the stock oil used.
http://www.shelldubai.com/industrial/tds/tellust.pdf
The numbers are pretty close to Castro Fork oil (10wt) on the chart you posted.
The CV O'Ring numbers are -018 & -013. Those numbers are for the round O'Rings that go in the "new" CV. The way you can tell the difference between old and "new" is the old CV is a cylinder with vertical sides and the "new" one is more cone shaped with angled sides. O'Rings are not interchangeable. The old style used a quad-ring or X-ring and that is why they got stuck. The quad ring didn't have as much mechanical squeeze as a round ring and little bits of oil would get past it, eventually filling up the inside of the CV so it couldn't fully close. Common problem with old style CV's.
IFP O'Ring is a -117
Can't help on the dust wiper. I'd be surprised if you could find it as a common part
You're not hallucinating, old Bullits did not have a compression adjuster piston in them.
http://www.shelldubai.com/industrial/tds/tellust.pdf
The numbers are pretty close to Castro Fork oil (10wt) on the chart you posted.
The CV O'Ring numbers are -018 & -013. Those numbers are for the round O'Rings that go in the "new" CV. The way you can tell the difference between old and "new" is the old CV is a cylinder with vertical sides and the "new" one is more cone shaped with angled sides. O'Rings are not interchangeable. The old style used a quad-ring or X-ring and that is why they got stuck. The quad ring didn't have as much mechanical squeeze as a round ring and little bits of oil would get past it, eventually filling up the inside of the CV so it couldn't fully close. Common problem with old style CV's.
IFP O'Ring is a -117
Can't help on the dust wiper. I'd be surprised if you could find it as a common part
You're not hallucinating, old Bullits did not have a compression adjuster piston in them.
Thanks MttyTee.
The 5th's I've got include a 2002 off the Bullit, 2003 off an IH SGS, and 3 newer VPFree versions. I just checked the CV from the Bullit shock and it is straight walled and uses quad seals. The last one I rebuilt was the 2003 and the CV in that one was slanted with o-rings. I'm assuming the VPFree shocks also have the o-ring type.
I guess I'm going to retire that Bullit shock for parts and not use its older style CV. I guess I'm lucky it never stuck on me because it saw a lot of action.
I'm going to try a slightly lighter oil for the next go round with the lower durometer main seal. I'm going to have to figure out the cSt numbers at ~20C to decide which. This shock will be used for slower techy stuff and jumping so I'm not so concerned with heating and high VI.
BTW, how much does that compression adjuster pistion contribute to compression damping? Does it make any sense to remove it when running the 5th on low leverage bikes?
The 5th's I've got include a 2002 off the Bullit, 2003 off an IH SGS, and 3 newer VPFree versions. I just checked the CV from the Bullit shock and it is straight walled and uses quad seals. The last one I rebuilt was the 2003 and the CV in that one was slanted with o-rings. I'm assuming the VPFree shocks also have the o-ring type.
I guess I'm going to retire that Bullit shock for parts and not use its older style CV. I guess I'm lucky it never stuck on me because it saw a lot of action.
I'm going to try a slightly lighter oil for the next go round with the lower durometer main seal. I'm going to have to figure out the cSt numbers at ~20C to decide which. This shock will be used for slower techy stuff and jumping so I'm not so concerned with heating and high VI.
BTW, how much does that compression adjuster pistion contribute to compression damping? Does it make any sense to remove it when running the 5th on low leverage bikes?
dhkid has done more playing around with oil than I have. I tend to stick with oil that is similar to stock numbers and adjust valving. Changing oil is a huge adjustment that changes the whole damping range.
As far as the compression adjuster piston, I'm on a Sunday and have been beefing that valve stack up with nice results. I would leave it.
As far as the compression adjuster piston, I'm on a Sunday and have been beefing that valve stack up with nice results. I would leave it.
165 lbs, 2.6 leverage ratio falling rate (an old Bullit with a 8.75 X 2.75 shock). On my higher ratio, rising rate DH bike the stock compression setup feels fine.
I included the specs from the oil that MttyTee provided and compared it to some others. Surprisingly the stock oil is much lighter than Silkolene RSF 5w, and only slightly heavier than Silkolene RSF 2.5w. I may try the RSF 2.5w for the Bullit.
danno, i think you got the leverage ratio for the bullit wrong, its 7 inches with a 2.5x8.5 shox. you get a bit more travel with the 2.75x8.75 shox. but you aren't light anyways so stock will be fine. i am not sure about the numbers, but a bone stock 5th ride much closer to the 5th with 5wt rsf then 2.5wt rsf. with 2.5wt there is hardly any compression damping on it. the only other thing i can think about is that the service center in australia doesn't use the same oil that the 5ths come stock with, because all the shoxs i have worked on have been to australia for a service before.
anyways, give it a try and post your findings back here.
mttytee, i forgot to tell you the mods that you talked about for the dhx and the 5th both work very nicely indeed. i am at a point where i wish i had more ride time to be able to ride both shoxs more and fine tune them further.
anyways, give it a try and post your findings back here.
mttytee, i forgot to tell you the mods that you talked about for the dhx and the 5th both work very nicely indeed. i am at a point where i wish i had more ride time to be able to ride both shoxs more and fine tune them further.
I bet we're all wishing we had more time to ride!
This is an 01 Bullit which stayed basically the same until the 07 revamp. With the 2.5 stroke shock it was advertised as having 7" of travel, but it doesn't. TNC and I think keen over on mtbr made careful measurements to prove it. I did the same thing myself and sure enough it's true. With the original 2.25" stroke shock it had about 5.9. With the 2.5" stroke it has 6.5" of travel, and the 2.75 gives about 7.15". I haven't checked the travel for the 2.75", but that's what's been reported by others.
I believe that the new one really does have 178mm (7") of travel.
I'll think about the oil issue for a bit until I get the new seals, and I'll let you know the result. I'm also contemplating replacing the seal, dropping the spring weight a bit because I'm not getting 30% sag, and maybe going with stock weight oil. I'm kind of torn on setup because I like the plush ride for trails, but I also use the bike for biggish dirt jumps where having more spring pop makes it more fun.
The new seals came in so I did a little swap.
I changed the main seal to a Viton 75 duro as suggested and I swapped the rebound needle o-ring. Since I just pulled off the main seal head (I think that's what it's called) so I didn't really have to do any bleeding. I just hose clamped a section of inner tube over the end of the main chamber so the seal head was submerged when I screwed it in. I also poured oil down the shaft center before dropping the rebound needle into place. I noticed that in screwing the seal head back on I lost about 1.5mm of IFP depth. I had it sitting at 45mm before the swap, so it's still OK.
What felt like CV 'stiction' before must have been mostly the high durometer stock seal because that feeling is gone now. It feels really smooth. Unfortunately due to a little New Years day crashipoo I can't really put the bike through its paces... yet.
I'm still running approximately stock weight oil (16 cSt @ 40C), and I'd still like to try something a little lighter. I tried to find some at the local moto shops, but no luck. That'll be the next change after I test out the current config.
I changed the main seal to a Viton 75 duro as suggested and I swapped the rebound needle o-ring. Since I just pulled off the main seal head (I think that's what it's called) so I didn't really have to do any bleeding. I just hose clamped a section of inner tube over the end of the main chamber so the seal head was submerged when I screwed it in. I also poured oil down the shaft center before dropping the rebound needle into place. I noticed that in screwing the seal head back on I lost about 1.5mm of IFP depth. I had it sitting at 45mm before the swap, so it's still OK.
What felt like CV 'stiction' before must have been mostly the high durometer stock seal because that feeling is gone now. It feels really smooth. Unfortunately due to a little New Years day crashipoo I can't really put the bike through its paces... yet.
I'm still running approximately stock weight oil (16 cSt @ 40C), and I'd still like to try something a little lighter. I tried to find some at the local moto shops, but no luck. That'll be the next change after I test out the current config.
Danno, just make sure the IFP won't hit the volume adjuster at full bottom. I don't have the numbers in front of me but you can always check by threading the shaft eyelet on before putting the bumper on and compress the shock with the volume adjuster off to see.
Also, with your Bullit you could wind the volume adjuster in a bit to help with the falling rate and if you could go in on the Beginning Stroke Adjuster too to help while jumping.
Also, with your Bullit you could wind the volume adjuster in a bit to help with the falling rate and if you could go in on the Beginning Stroke Adjuster too to help while jumping.
MttyTee, thanks for all the help. You were certainly right about that seal. Now when I push on the seat what I feel matches how I'd expect the CV to work based on your explaination. Before changing the seal I'd push on the seat and I could feel it give after which the force needed to keep it moving would drop. That was stiction. I'm going to continue to experiment with setup. The 5th is fun to play around with.
I'm running the volume completely open at the moment and I was going to check the numbers before turning it in. I figure from your 25.75mm depth (posted earlier in this thread) when the shock is bottomed I should be at:
25.75mm + 70mm (stroke) / 4 (volume ratio) or 43.25mm.
I was right at 43.5mm so I think it's OK even if I wound the volume all the way in. I'm going to leave it open until I find it bottoming out though. I do have a 350 spring on the shock which is a bit high for my 165 lbs, but I don't want this bike to be a couch like my DH. :biggrin:
Do you guys have the actual tool to push the ifp back in, or what kind of method are you using? I found it really hard to get it back in there.
I push it in with my thumb, and yeah it's a bit tough. Make sure you have the seal head/main pistion pulled out when you do it though.
FWIW, I found I had to have the oil level about 1/2" above the top of the tube as to be able to get the air out from under the ifp. It had to be tipped quite a ways while submerged because it's concave.
I also set the ifp level a little shallow and then once it's all together I loosen that little bleed screw about half way and using my thumb once again I force oil out until I get the ifp depth spot on. Just don't take that screw all the way out or you'll probably get air into the shock.
Next time I will do it that way, I´ve got 4 5th elements, so far I´ve done only one. Thanks!
danno- i dont quite understand what you mean by having the oil 1/2" above the tubes. are you referring to having a plastic bag around the tubes so that you can have the ifp and main piston go in to the tubes totally submerged in oil?
i have found that its not really necessary. the steps i take is this:
1) make sure there is no air in the passage between the main chamber and reservoir. i do that by sticking the main piston in and cycling it until no air bubbles come out, you have to do it with the beginning stroke compression at full open and full closed so that oil flows through both circuits.
2) fill up the oil till it just overflows the piggyback side. then carefully put in the ifp sideways, and once its all under the oil, orientate it correctly. it does take a bit of force to get in as the o ring on the ifp is very hard.
3) make sure there is no air in the main piston, cycles it until there is no more air bubbles. then i set the ifp depth plus about 5mm for when you close it up. i normally do this with the shox at bottom out, so there is no chance of getting air into you bled main piston. then close it all up. i dont have excess to imperial allen keys so i have to do it this way.(the bleed screw allen key is imperial.) it takes a couple of goes sometimes but i always get a perfect bleed.
i have found that its not really necessary. the steps i take is this:
1) make sure there is no air in the passage between the main chamber and reservoir. i do that by sticking the main piston in and cycling it until no air bubbles come out, you have to do it with the beginning stroke compression at full open and full closed so that oil flows through both circuits.
2) fill up the oil till it just overflows the piggyback side. then carefully put in the ifp sideways, and once its all under the oil, orientate it correctly. it does take a bit of force to get in as the o ring on the ifp is very hard.
3) make sure there is no air in the main piston, cycles it until there is no more air bubbles. then i set the ifp depth plus about 5mm for when you close it up. i normally do this with the shox at bottom out, so there is no chance of getting air into you bled main piston. then close it all up. i dont have excess to imperial allen keys so i have to do it this way.(the bleed screw allen key is imperial.) it takes a couple of goes sometimes but i always get a perfect bleed.
I hose clamp on a couple 2" long pieces of inner tube instead of the plastic bag. I partially do it not to get oil everywhere, but I also had a hard time getting the air out from under the ifp without having the oil level somewhat above the top of the tube edge. In order to tip the ifp flat it had to be almost right at the top of the tube and because of that I kept getting a bit of air trapped underneath of it.
I do the bleed pretty much the same way you described and I've never had any signs of air trapped in the shocks.
And yeah, that allen for the bleed screw is 3/32". I partially stripped one of them trying to use a metric wrench.
I've changed the main seal to the Viton 75 in the shock on my Bullit and just today my DH bike. Got to have something to do to the bikes while I'm recovering from injury! I even rebuilt a couple Romics, which are way trickier than the 5ths.
Just to try something completely different I'm going to pick up some Golden Spectro Ultra Light (10.4 cSt@40C). I'll build up another shock I've got with it and try it out on the Bullit.
dhkid, I tried to make a little drawing that hopefully shows why I think the oil level has to be ~1/2" above the top edge. I found this out when I tried inserting it without an extension. After I inserted it I checked the bleed by adding the extension, raising the level, and then tipping the IFP back up while submerged. When I did air bubbles came out.
Anyway, I hope this makes some sense...
Danno, did you put a bleed screw in the IFP? B/C that is not stock on 5th's?
MttyTee, we were talking about the bleed screw (I'm sure we're using the wrong name for it) that taps into the BSC adjuster hole. It seems like a convenient way to let a little oil out.
danno- i never have problems with air getting trapped there, just do it carefully. you will notice that air wont get trapped because the surface tension effects of the fluid will sorta go up into the little pocket before any air can get trapped.
your way is of course more fool proof and will give a perfect bleed all the time, just saying its possible to do it with less, thats all. the only thing i dont like is opening the bleed screw, its easy to get air in there but makes getting the ifp depth much easier. on a dhx i close the bleed screw (which is on the ifp) after i have closed the main piston side. so much easier.
your way is of course more fool proof and will give a perfect bleed all the time, just saying its possible to do it with less, thats all. the only thing i dont like is opening the bleed screw, its easy to get air in there but makes getting the ifp depth much easier. on a dhx i close the bleed screw (which is on the ifp) after i have closed the main piston side. so much easier.
I try hard not to get air in through that bleed screw. I put pressure on the IFP and then loosen the screw just enough so oil starts slowly dripping. While maintaining the pressure I close the screw, and check the IFP depth. I repeat until I get the depth right.
I've got a 2005 DHXc that probably needs an oil change. Any idea on the type of oil in that shock or what the IFP depth is supposed to be. It's a 7.5" X 2" off my RFX.