Keep it in the family, DRZ250 Cartridge forks onto a DR650

[warewolf]

Originally Posted by Eddieb

Interestingly they don't show any sort of adjustable shim stacks and according to their book the diagram shows everything in the forks, nothing comes apart any further than is shown.

Tom Jones moment... "It's not unusual". It's just that they don't expect you to service - and don't sell separately - the shim stacks so there's no exploded diagram.

Anyway... typically on USD forks, part #15 is the compression (funnily enough, aka base) valve complete assembly including shims and adjustment needle. Is your adjuster needle stuck in the assembly? Might be worth taking the base valves to a suspension guru, they might be able to fix it.

The rebound valve (aka mid-valve) assembly is trickier to spot on that diagram for RWU forks, but I would guess it is part #30. On compression its pushed into the oil-filled cartridge, and then on rebound it acts like a screen door closer.

Or have you not got the cartridges out yet? The shim stacks should be pretty obvious once you have them in your hand. Again, a suspension guru most likely can fix it, unless they are really, really poked.

[bkoz]

Originally Posted by Gryphon12

Aren't shim stacks for Cartridge forks? DR650's are damper-rod forks. That's the whole point of this thread. You don't fit cartridges inside; you replace them with cartridge forks from the DRZ-250. Or am I missing something?

Yes that is the point of the thread. But I was throwing the idea around of removing the damper rods from the DR650 and installing the DRZ250 cartridges vs changing the whole fork assembly and having to play with brake fitment. Just thinking out loud in cyberspace.

[bkoz]

Originally Posted by Eddieb

So I popped into my local dealer tonight and they copied the exploded diagram for the DRZ250 forks out of their documentation.

Interestingly they don't show any sort of adjustable shim stacks and according to their book the diagram shows everything in the forks, nothing comes apart any further than is shown.

I also asked them to find out the price of part 16, as the adjuster screw is stuck in both my fork legs and I may not be able to get them unstuck. There was no price on file as that part has never been imported here individually by Suzuki NZ.

Sorry for the crap pic, I don't have a scanner.

See Warewolf's post.

He is absolutely correct about the manufacture not showing more info on the forks. They don't want you going inside them. The same goes for shocks.

As far as your seized adjusters it is best to strip the forks down. It will be much easier to make any repairs. The adjuster bolt itself is very soft, beware.

Take as good look on the interwebz for a video or disassembly pics. Maybe even snoop around some Honda XR forums, I believe the XR400/XR250 forks are very similar, if not identical.

[Eddieb]

I've been looking for disassembly pics or video for these for a while and either I'm not using the right search terms or there's nothing out there. I could find lots on other cartridge forks, mostly USD's but nothing for these.

After everyone's assistance I had a closer look at things today.

The lower bolt and adjuster


The adjuster is seized


That looks like the base of a shim stack in there


The shim stack looks like it's pressed in with an o-ring to seal things

[Eddieb]

At this stage I am not going to alter the valving as I don't know how it will behave as it is. I'm planning on getting the adjusters working then refilling the forks to factory spec and seeing how they perform over a month or 2 and what different adjustments do. After that I will decide if I want/need to update the valving.

[warewolf]

Originally Posted by Eddieb

refilling the forks to factory spec and seeing how they perform over a month or 2 and what different adjustments do.

Good plan.

I've never seen anything quite like that setup, but then I'm not that experienced. I never touched my DR-Z250 forks apart from the odd minor clicker adjustment, 'cos I paid a suspension guy to service them. All he did was add a little more oil to stiffen the latter part of the stroke, which he did a couple of times over successive services. He used to watch me ride at club events etc when he caught up to me, and tweaked from there.

[kiwipeet]

Very cool. Saw link on fb.. hope I can find my way back here for a nosey tommorrow :)

Sent from my HTC One V using Tapatalk 2

[Eddieb]

Originally Posted by eakins

hit the nut with an air gun and it will spin faster than the internals and come off.

Originally Posted by warewolf

Put the spring and fork cap back on to hold the cartridge for you.

I had to take my car in for it's WOF (Warrant Of Fitness, 6 monthly mechanical check) this morning so I put the spring and cap back in the fork leg I couldn't get the bottom screw out of and took it down to the garage with me. 1 quick blip on their rattle gun and it undid.

I'm away for the next 10 days so there won't be any further progress for a little while.

[Eddieb]

Originally Posted by Eddieb

The lower bolt and adjuster

I rang my dealer back today and they had received a price from Suzuki NZ for replacement lower bolts with the compression adjuster in them.

$214NZ each!

I'm really hoping I can salvage my ones, otherwise it's Ebay time.

[el capitan]

Drown them in a glass of WD40 and let them sit for some days - it is quite likely you will be able to work them loose afterwards. We had a similar problem on a mounted shock of a 91-Ducati 900 SS. It was solidly stuck in the beginning, but could be loosened and normally adjusted afterwards. No problem since.

[Eddieb]

I've managed to free up one bolt adjuster after soaking it for a week and some brute force by a friend with the right tools, but the 2nd adjuster is resisting all attempts to get it moving.

Some Googling also indicates that as usual we get shafted for parts in NZ. I've been quoted $214NZ for replacement adjusters, but WorldOfPowerSports.com lists the part as $86.33US each, thats about $106NZ at todays exchange rate.

http://fiche.worldofpowersports.com/...N---FRONT-FORK

[warewolf]

Originally Posted by Eddieb

the 2nd adjuster is resisting all attempts to get it moving.

Give it some heat, too.

[Eddieb]

Originally Posted by warewolf

Give it some heat, too.

I don't have anything to give it any real heat and time is running out before Christmas where I have a couple of multi-day trips to do and a 2500-3000km trip at the end of January so I'm going to reassemble the forks with only one compression adjuster working and fit them to the bike for the break, then review things next year.

I may be stuffed anyway as from what I can tell the part is no longer available from Suzuki, so unless I can find a wrecked set of DRZ250 or DR350 forks I may not be able to get another adjuster.

Does anyone know about reassembling cartridge forks, do you just pour the oil back in like a damper rod fork and do you have to do funky things with the cartridge? and does anyone know what grade and volume of oil is required. There's not much info out there that I can find on these forks.

[warewolf]

USD open cartridges, you put your hand on the top of the fork tube and compress it to create pressure. This forces the oil in and the air out of the cartridge. Dunno about those RWU forks though - see if you can do something similar on assembly?

Otherwise try ask here, if you haven't already: Drz250 Thread

[kawagumby]

Hi guys,

Can't you just swap the fork lower legs between the 650 and 400, thus keeping the 400 internals and the 650 brake mount? Or is the base compression stack ass'y a different diameter thread? The lower legs, after all, are just an open tube - and if the the diameters and bushings are the same -

Regarding the spring rates, I'm at 160 lbs and what works well for me on my WR250r street bike at 300 lbs wet is the stock springs at .47 kg/mm (both on and off-road). I run .42's on my 220 lb dirt bikes. So, with the 350+ DR, I would think you're looking at at least .48's for any fairly aggressive off-road work, more if you're heavier than I am.

I'm following this thread because I'm thinking about getting a DR.

edit: The DR650 manual calls for 10 wt oil. With regard to the cartridges, to get the air out you slowly cycle them through the range of motion until you get a firm feel (cycling out the air bubbles). You can change the amount of travel by adding more oil for less travel & more firm toward end of travel (if you bottom too much, for example), and less oil for more travel, less firm toward end of travel. Always stay within the recommended oil volume range tho'.