How To Rebuild The WP Fork Inner Cartridge

hey what's up everybody Dustin here with Rocky Mountain atv/mc and today I'll be showing you how to rebuild the inner chambers cartridge from AWP open chamber style of fork that we pulled off of a 2015 KTM 300 X CW alright so inside of our cartridge we've got a couple pistons with some shims witches are evolving along with some oat rings in a wear Bend that sits on the rebounding valves piston now all of these parts are going to wear out over a period of time and use and will eventually need to be replaced now you will definitely want to freshen up the cartridge especially if you've been experiencing a loss in compression dampening force and that's especially if you're experiencing that through the mid stroke when the forks are under compression so today we're gonna be showing you how to rebuild this cartridge now the process that we're gonna show you here today can be applied to many KTM and Husqvarna dirt bikes that are running an open chamber style of fork however when it comes to working on your bike always be sure to reference your service menu for those specific procedural details alright to do this job you are going to need a heat gun along with a fork rebuild kit now the kid that we're gonna be using here today's from pivot works it comes with everything that you're gonna need to do a complete rebuild including your dust seals oil seals bushings and along with all the o-rings and other parts will need to rebuild the cartridge now keep in mind that this kit does fit a wide variety of different bikes so for this video that we're gonna be doing today it's going to come with more parts um we're actually going to need so just keep that in mind now we do offer other kits that are more specific on our website so be sure to check that out now you will want to have some fork oil some contact cleaner and then two special tools here from race tech we've got our special vise jaws along with the cartridge holding tool you will want to have some thread Locker some medium strength and high strength as well as some sealant over in grease then some basic hand tools with some compressed air a torque wrench some rags rubber gloves and safety glasses keep in mind that these steps are the exact same for of both of the forks now if you need help with getting to this point with the cartridge out of the fork you can check out our how-to video on the WP 48 millimeter open chamber fork with spring preload adjuster now if you're curious as to whether or not if you have these Forks you can look at the fork and you'll notice that the spring preload adjuster will rotate independently of the fork cap itself then we've got several pin holes right here that require a pin spanner type of fork cap wrench in order to disassemble them alright now when you start out you're definitely going to want to put out a few rags that are clean just so that way as we pull the cartridge apart we can set out the parts and the order that they are removed from the cartridge now to begin we're gonna take our cartridge extend it like so we're going to remove the fluid barrier slash lock nut just unthread it we're gonna set that aside once we get to this point we can slide the dampening rod through the bottom of the cartridge it's gonna come out the base of it here now once we've got this separated like so we can remove our spacer and our spring seat now something I want to point out real quick before we get this mounted inside of there you will need a twenty two millimeter box open-ended wrench that is fairly thin as you can see this is a thin wrench and we barely have enough room to get it on to the sleeve part of our cartridge now you will also want to have a tool of sorts for this we're going to be using a number three screwdriver but something that can fit through the slot holes and that doesn't leave a lot of slack inside of there because once we have this inside of our special vise we're going to be using this to hold it in a fixed position while we heat this area and then remove it because we will be applying a lot of torque all right and when you're clamping this into the vise with the special vise jaws you want to make sure that you're just holding the tube in place you don't want to put too much pressure on it because if you do you run the risk of actually collapsing the tube it's not very not a very thick wall to it now once you've got that secured inside of there we're gonna take our heat gun we're gonna heat this area of the sleeve because this is where our threads are 250 degrees Celsius or approximately 122 degrees Fahrenheit alright so once we've got that nice and hot we're gonna take our screwdriver it's about the same size diameter as the holes that are in the bottom of this cartridge we're gonna slide that in through so that we can hold it in a fixed position that way our vise isn't putting too much pressure on it and we'll take our thin 22 millimeter open-ended wrench and place it on to the sleeve here and then we are going to break it free all right so once you get this unthreaded you're gonna want to take it off with your open-ended wrench because it is still very very hot next we can begin working on the rebound valving on our compression shaft here now before we do that we're going to spray down some contact cleaner to decrease it and rid it of any of our work oil as you can see on the rebound valving piston you can see our wear band is coming off we've been having some problems with this just blowing through the mid stroke when the forks are under compression so this is our reason for getting into these Forks so if your wear band is coming off it's going to come off at some point right now as good as any time now next we're going to pull out to the adjusting rod and then we can place this into our vise now what's cool about to the shaft holding tool from race tech is it's got these little pins that are in going to gauge with it that are on the special vise so we're gonna set this on there like so holds them into position then we're going to place this into the shaft holding tool and for this fork we're gonna be clamping in this this into the position of the 12.5 now again the same thing here when you're clamping this in you don't want to apply too much force because then you've run the risk of collapsing the tube so now once we have that inside of there we can take our 10 millimeter open-ended wrench or socket if you prefer and we can begin to remove this nut now as you can see when you remove this nut you'll notice that at the bottom side of this not the way that it's oriented now it's gonna have a collar on it so just keep that in mind when it comes time for reassembly and as I'm taking these parts off I'm just gonna simply take them off and then set them right back down that way when I go to put them on there's no confusion as to if they're upside down or right side up alright so now we're gonna take our straight pick tool here we're gonna place this into the end of the dampening rod like so then we're going to lift up on just the shims here now may be a little bit difficult to work them up off of the threads there so just take your time work them slowly make sure that you've removed all the little shims and then just like I've taken them off I'm just gonna set them right down on the table just like that and once we get that off of there we're gonna be removing the piston as you can see some shims are sticking to the bottom of it that are on the other side so we're gonna make sure that those do not come off with it now once you pull this off of there again play close attention to the orientation on the outside of here on this triangular looking side we've got small holes and then on the bottom side of it we've got much larger holes so again when you take this off just leave it right side up the way that it is set it down on your rag and order that it came off then we're gonna pull off the remaining shim so again use your pick tool because this is the last set of shim so I'm just going to leave it like so all right then we've got a spring to remove this is not directional but still keep it in the same orientation order that it came off now for this next piece that we're going to be removing we do want to heat this up with our heat gun and again we're gonna bring it up to about 50 degrees Celsius or about 122 degrees Fahrenheit all right now to remove the tap rebounded we're gonna be using a 17 millimeter open-ended wrench or a socket whichever you prefer now again remember be careful when removing the tap rebound as this is extremely hot all right now once you've got the tap rebound removed we can remove the spring that sits just beneath it all right now here on the tap rebound we've got the part that controls our adjustments at the top of the fork now this doesn't usually come out and with the tap rebound it usually stays inside of the dampening rod inside of there so if you pull your tap rebound and this is not on there it's inside of your dampening rod and you will need to pull this out now again while we have all of our parts removed we're going to go through and clean everything with contact cleaner get them degreased on the tap rebound you can see we've got some thread Locker that is residual just left on there we're gonna want to take our stainless steel brush and scrub those threads make sure that everything is completely clean and then spray it off with air we don't want any oils or any dust on these parts when we go to assemble them alright so now that we've got all of our parts removed and disassembled there are two o-rings that we are going to be replacing one on the tap rebound as well as the adjusters valve point here this small oring now the kits gonna come with several different sizes of O rings so what I would recommend that you do is line them all out sizes largest to smallest and as you remove these o-rings from the components go take them and set them over next to the one that it most closely matches in diameter and then we'll be using those two place these old rings with all right so now that we've got our rings replaced we can begin the rebuilding process now to start we're going to take this spring that's got the plastic collar inside of there we're gonna place this facing down onto our dampening rod press it on there so it's nice and snug so we're gonna take a little bit of a ring seal grease we're gonna place it onto the o-ring here and then we are going to place it inside of the tap rebound now when we place it in there we're gonna press on the rebounding valve just enough to store the spring compresses slightly to make sure that it's seated inside of there and once we've got that we're going to apply some medium strength threadlocker to the threads then we can install this into the dampening rod in torque to 13.3 foot pounds or 150 9.6 inch pounds all right so once we've got that torqued on there we're going to mount this small spring and we'll take our pic with our shim stack place the pic inside like so and we'll let our shim stack come down we'll gently work it on there now before we install the piston we need to make sure that all the shims are lined up this needs to be able to compress the spring without it getting tangled up inside of there once it's set like so we can take our pick tool we're gonna use this to hold the shims down then we're going to install the valve all right so once we get the piston situated on there we can take the upper shim stack we're gonna place it on to our pick set the pick inside of there like so then we're gonna let this come down and slowly and gently work it on to the tap rebound here all right now something I want to point out real quick to you is the lower part of the upper shim stack you can see these triangular shims they actually move right so we need to make sure that these are aligned over the holes inside of the piston just like this all right so once we've got our shims aligned with the pistons opening we can now install the nut with the collar so we'll take out our pick tool we're gonna take some medium strength threadlocker we're gonna apply just a little bit to the nut here and we can thread the nut on to the tap rebound now you want to take your time get with getting this started it may feel like it's stripped out or it's not going on the correct way so take your time make sure that you keep the nut nice and square it is going to thread on there it just feels that way because the end of the shaft has been pained so those threads have been expanded just a little bit so take your time with this don't rush it really look at it nice and closely make sure you're nice and square now as you're threading this nut on it's not a bad idea to go ahead and push down on your piston to make sure that it's still actuate against that spring and that the bottom shims are able to make it over that shoulder now it's not a bad idea to hold it down thread this on there a little more alright so we're gonna take our torque wrench and we're gonna torque the 10 millimeter nut to 3.7 foot pounds over 44.4 inch pounds now when you're torquing this on keep an eye on the triangular shim and make sure that it's it stays covering the opening on the piston all right so now that we've got this rebuilt the last step of the service menu calls that we do is to lock the nut and what they mean by that is to take a punch and a hammer you're gonna place it on to the shank that protrudes from the nut and then strike the punch what this will do is it will flange the shank that protrudes from the nut over on to the nut so that way it is not able to come off during operation however by installing a thread Locker we can achieve the same effect all right so now that we've got that reassembled we can now take this out of the vise we can remove our shaft holding tool then we're going to clamp the cartridge into the vise now again remember to not clamp this in there too tightly or you will damage it now for the next part we're gonna take the wear band that comes in the kit we're going to lubricate it a little bit with some fork oil I just poured some into the cap here just gonna coat the wear band alright so once we've got this lubed up we're going to take our rod here we're gonna place this on to the piston as you can see it's a little stiff to work with so you'll have to hold it together with your fingers once you've got to about there you're gonna want to hold the part that connects together with your fingertips so that it stays around the piston then we're gonna bring this over to the cartridge and we're gonna gently and slowly set this inside of the cartridge now you'll want to take your time with this step as we don't want any part of the wear band to get hung up on the outer edge so just slowly take your time and work it inside all right now once we get this placed inside of there we don't want the piston to make it more than about half down the distance of the cartridge we don't want this to make it down all the way out through the bottom or else that wear band will come off of the piston so just make sure that it's sitting about in the middle next we're going to install the sleeve onto the cartridge now before we do that we're gonna apply some high-strength threadlocker to the threads here all right now before we install the sleeve I'm just gonna take a little bit of fork oil and I'm gonna place it into the inner diameter here just to lubricate it before we install it then when you place this on to the rod alright now the torque on this is 33.9 foot-pounds and remember that you don't want to clamp this too hard into the vise so when you're putting pressure on this sleeve to get it threaded on a thirty-minute 3.9 foot-pounds you're gonna want to take a screwdriver and place it into the bottom of the cartridge that way you can kind of hold it and apply the appropriate amount of torque next we can mount the spring seat and washer then we can install the fluid barrier or lock nut you're gonna want to thread this all the way onto the shaft and then we can install the adjusting rod now once you get this place in here you want to press down on it with your fingertips to make sure that it's working that it's pushing against the spring inside of the valving and again you don't want this to protrude more than seven millimeters so now that we've got this taken care of we can pull this out of the vise and then we can start on the compression damping fitting all right so we're gonna clamp the compression dampening fitting into our vise with our special vise jaws clamp it in there so the shim stacks facing up and we're going to remove this nut with our seventeen millimeter open-ended wrench so once we get the nut removed we can remove this spring notice the smaller end of the coil is going to be facing down and we can remove our washer then we can remove our piston be sure that the blower shim stack does not come with it now when you pull this off you'll notice you've got the larger holes on the top and then you've got the smaller holes on the bottom just make note of that for orientation then we can pull off our lower shim stack next we can remove the o-ring and once we get the rubber o-ring removed we can remove this copper sealing washer and then on the piston itself we have an additional earring that we will need to remove now once we've got those o-rings removed we're gonna place them next to the new ones that we have lined up here and we're just going to match it up with the one that fits the best now before we install this on to the piston we're just gonna take a little bit of oring and seal grease just kind of lube it up alright so now we can install our ring onto the piston and we can lubricate the o-ring that's gonna be placed back on to the dampening fitting but before we place this on to the dampening fitting we are going to install the new copper washer then we can install the new o-ring next we can install the shim stack with the smaller shims facing down now when you're placing these on to the compression dampening fitting just take your time be careful with them don't force them on as we don't want to bend them alright so once we've got those on there we can place our piston onto the compression dampening fitting again with the larger holes facing upwards then we can install the washer followed by the spring with the smaller coil facing down and then before we install our nut we're going to apply just a little bit of medium strength threadlocker to the nuts threads we're gonna torque this to 2.2 foot-pounds or twenty six point four inch pounds now again when you're threading this on you want to make sure that it's nice and squared that you're not gonna cross thread it so take your time with this now the initial installation of this nut is going to give you a little bit of resistance that's totally normal then once you get to a certain point it will begin to rotate much easier more freely and when you get to that point is when you want to put your torque wrench on and torque it to spec all right now when you're threading this on and into place you want to make sure that the washer is centered over the piston now the reason for that is the center diameter of the washer is actually going to sit around the lower part of the nuts collar if that makes sense so basically you need to make sure that it doesn't get hung up on its edge make sure that it's completely centered so that way we can get this seated fully into the position that it needs to be so as you're installing this just make sure that your washer when it's sitting on top of the piston is nice and centered all right now the last step for the service manual would be to lock the nut on to the assembly by painting the end of the part of the threads here that protrude from it with a punch and a hammer however using thread Locker you achieve the same effect now if you need help with reassembling the rest of your Forks be sure to check out our how to video the WP 48 millimetre open chamber style of cartridge fork with spring preload adjuster and that's it that's all there is to it when it comes to rebuilding the cartridge now by doing this you're definitely going to be able to get the most out of your suspension now if you have any questions as to what we've done here today feel free to leave us a comment below and we can get an answer back to you and keep in mind that all parts we've used here today can be found on our website so be sure to check that out that's it for me i'm dustin with rocky mountain thanks for watching and keep the wrenches turning [Music]

Channel: Rocky Mountain ATV MC

Views: 26,028

Rating: 4.9269404 out of 5

Keywords: Rocky Mountain ATV/MC, rmatv, rmatvmc, atv/mc, atvmc, motocross, rockymountain, dirt bike, motorcycle, parts, accessories, rocky, mountain, how to, how-to, rebuild, replace, rebuild inner cartridge, cartridge, chamber, 48mm, forks, fork, fork rebuild, ktm, ktm 300 xc-w, 2015, fork cartridge, wp forks, wp inner cartridge rebuild, fork seals, o-rings, ktm forks, wp 48mm forks, how to rebuild inner fork cartridge, wp inner fork rebuild

Id: jMDwgZqK7oM

Length: 18min 59sec (1139 seconds)

Published: Tue Jan 23 2018