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Newer xr cartridge forks or usd conversion?

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I have an '88 xr600r and love it, but, the front forks SUCK!!! I do have progressive springs and fresh atf with an ounce over recommended on each side. I am a big dude at 285. What my question is, do I end up all that better off doing a full usd conversion that will probably end costing at least 500 bones or find some newer XRL forks and respring? I mostly ride single track and desert with some dual-sporting. Also had the rear rebuilt and resprung. The crappy part is I had a set of forks with triples from a 91 yz that I was gonna graft onto my old xr5, but sold them to help finance the purchase of my current ride. The yz stem looked like it would fit with a little machine work. Any help would be appreciated.:cheers:

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As far as I know, 1991 was the last big change for the XR forks and that design is still used on the 650Ls.  Different springs and valving, but still the same basic conventional fork.  You can make those years better by revalving and respringing, but really, nothing is going to be better that a newer set of USDs.  But if you are going to go through the trouble, don't use older USD forks, get a set off a newer CRF 450 or 250.  Ask an 89 CR250 owner and they will tell you those first generation USD forks weren't exactly the best.  So go for the gusto and get something that is newer.

 

Another thing to consider is your riding.  What is it that sucks about the forks you have?  To soft, too hard, no enough tuning ability, etc.  If you are riding hard off road with a lot of bottoming out and the need for better compression and rebound adjustment, then go with the USDs.  If you are just cruising around and enjoying the scenery, then the older forks may be okay for you.

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Thanks Big Red. I do a wide range of different riding, but when I ride hard off-road over whoops and rough terrain is where the stockers really SUCK. They don't bottom because I resprung and adjusted the dampening with more oil. They really just don't have any tunability at all. Either way too soft or way too hard. Maybe for the cost, I should try the newer xr cartridge forks with maybe a fork brace. I could always sell them later if I don't like them. :excuseme:

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If you do the math, you'll be spending the same amount of money. I have a XR6 and found a pristine 2005 CRF450R complete front end for $225(THAT'S CHEAP!). Conversion bearings were under $70, oversized rotor was $120. Front tire, $50(New, craig's list). And I still need levers. I hate the stock ones.

 

Also, the newer the better. Try to get 2000 and up.

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USD and conventional work equally well if sprung and tuned for your weight.  There is not "USD is better" if both are setup properly.

At 285lbs even if you spring them right, the valving won't work (as you've discovered) with those stiff springs.

USD typically increase the turning radius, sometimes substantially.
Later year 600 forks can be very good when setup. 

PS- at 285 both are going to need different springs and valving, thus making the USD much more expensive.  FWIW

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RaceTech's spring database says that your 1988 XR600 forks use the same springs as the later cartridge XR600 forks.  So you could reuse your stiff springs in the new forks.  Of course, you'd still need to change the valving.

 

1992+ XR600 forks (I think that's the year they changed to cartridge style) will bolt on, saving a lot of the cost and hassle of the conversion aspect of USD forks.  I think XR650L forks will also bolt on and are basically the same design, but slightly shorter.  XR400 forks are a slightly better design, and will also bolt on; I think they're slightly shorter also.

 

The later forks mostly have the larger 17mm front axle, so you'll need to swap wheels or convert the wheel bearings/wheel collars/wheel center spacer.

Edited by heart_of_darkness

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If you do the math, you'll be spending the same amount of money. I have a XR6 and found a pristine 2005 CRF450R complete front end for $225(THAT'S CHEAP!). Conversion bearings were under $70, oversized rotor was $120. Front tire, $50(New, craig's list). And I still need levers. I hate the stock ones.

 

Also, the newer the better. Try to get 2000 and up.

did you have to shim the bearings at all?

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did you have to shim the bearings at all?

 

Yes, the conversion bearings do require a shim (just a washer, basically).  The shims come with the bearings.

 

Edit: the conversion bearings come with two shims.  A thin shim to give the same total bearing height, and a second thicker shim to compensate for the difference in steering stem length.

Edited by heart_of_darkness
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YES! First shake down went well. Second outing I flipped the bike going up a steep hill climb and broke, bent all kinds of parts. Rode her bruised up the rest of the day.

 

While repairing her I lifted up on the front tire and heard a clunk. It needed another shim.

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YES! First shake down went well. Second outing I flipped the bike going up a steep hill climb and broke, bent all kinds of parts. Rode her bruised up the rest of the day.

 

While repairing her I lifted up on the front tire and heard a clunk. It needed another shim.

any specs on what shim height is needed

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Yes, the conversion bearings do require a shim (just a washer, basically).  The shims come with the bearings.

 

 They must have started doing that later, cuz mine didn''t and it was common discussion on what size were needed to source elsewhere. I got from McMaster-Carr, they were 1mm shims, but I dont' remember if you use more than one or what the diameter size was. 

Edited by MindBlower

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hey tre, you can do both...this is(just sold the bike) my 88 with usds:

xr600021-3.jpg

 

and this before usds with "cartridge" 96 forks and rsw brace:

honda013.jpg

 

both succesfull transformations...success depends on how and what you ride...also its the litlle details like year and fork model that can make a big difference on how expensive or not the swap turns out to be.

 

If you would like the little details Id be gld to help by pm...I used to have a usd swap thread somewhere around here for those on a budget. but I cant find it anymore...

 

cheers

Edited by elsalvadorXR6

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Shimming is needed to achieve the correct install height(DUH). Usually the same height of the original bearings. Of course I read every single thread on the conversion and went EL CHEAPO route. So far so good, just worried about longevity cause now I'm riding faster for longer periods of time. Someday I'll switch over the EMIG stem for peace of mind.

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I'm currently mocking up USDs using the conversion bearings.  The bearings now come with two shims per bearing, and using all of the supplied shims (four total) seems to work out. 

 

All of the conversion methods have compromises.  I've read of four ways:

 

1)  The conversion bearings are nonstandard and require shims (although the shims are in compression and are not a weak spot).  It costs $60 for two bearing kits. 

 

2) Using bushings with the stock steering stem makes a potential weak point at the lower pressed on bushing if not machined correctly, and positions the upper triple lower down than stock (although, it's still within the acceptable range on the forks).  The cost would be probably half an hour of shop labor. 

 

3)  I haven't used the Emig conversion stem, but if it's the same length as the XR stem it would position the top triple too low (but again that's probably not a concern).  I think it costs $180 total with the top bushing.  The Emig stem seems to be probably the strongest and cleanest method, but also the most expensive. 

 

4)  Or paying a machinist to turn the CRF stem to the same specs as the Emig stem.  The cost at normal shop rates is probably more than the Emig.

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I did #2 basically...machine shops are cheap and good here...steel sleeve...no strength issues since you dont TURN down anything...a lot of guys go this route only ti suffer catastrophic failures, albeit on other bikes havent seen it happen on our bikes

 

lastly if you look at my thread that horri so nicely put by searching specific model usds like showa 2002 and up twin chambers you dont even have to buy a caliper relocating bracket...can use your stock odometer just use the crfx wheel and speedo attachment,etc...

 

 

you can save a lot of money...dont need to deal with custom bearings and shims...and dont "need2 fancy steering stems...again needed being the key word here

 

lots of ways to do this

 

anywhoo good luck to all trying them out!

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I'm going your way when I install mine Christian,,easy,,no fuss..KISS principal rules..Can't see using the XR stem and a bush is going to weaken anything,,I'm not going to be doing loop the loops on the thing,,Hope you find another bike or garner enough cash to get another..We need you back fulltime..A man needs more than poohey nappies and good cooking.. :jawdrop:..Brians probably got enough spares leftover from his rebuilds and further rebuild rebuilds to provide you with all the bits required for an entire bike.. :lol:

Edited by Horri

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specific model usds like showa 2002 and up twin chambers you dont even have to buy a caliper relocating bracket...

 

The showa USDs up until, I think, 2003, use the same caliper bracket.  Later years used a different bracket (but the same caliper).

 

Yup, the CRF/x front wheel and odometer hub can be used.  Be aware that the X model uses a different front axle than the R models, so it's easiest to source the wheel/odo/axle together although most ebay sellers seem to separate all the pieces.  It's unfortunate that Honda designed a different hub for the X models; previously, the XR and CR wheels were similar and the washer thing with the two odo drive nubs could be added to any wheel to function with an odometer hub.

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I cant remeber exactly but 98-2003 showas are similiar then they change again till the present...all I know is that 2002 forks or so you dont need to do anything about a relocating bracket...you just use 2 long bolts intsead of the xr bracket which uses one long and one short bolt to attach the caliper. You also need not change the brake hose line, or even detach anything from the mc.

 

I wish Id new when the cutoff is for the no mod brake caliper bracket swap is(I did when doing the swap)...if its 2003 then for those shopping Id search for 2000-02 forks just to be safe. Twin chamber showas off the crf/x bikes. 250x are a little more plush than the 450x. Also my forks where off the cr250r motocrosser.

 

Like heart of darkness says, the crfx hub and axle are different...I lucked out and found an excel black wheel for a 450crfx for less than $100 then steve just bought the axle(hollow btw you save wieght), spacers, odo drive and presto all I did was install new bearings

 

HORRI thanks for the well wishes....

Ill get back on an xr6 or any xr for that matter someday...for now Im workiing on my sailboat...new chainplates, bulkheads, paint and gelocat...yeah fun!

 

peace

 

ps. btw I used a cr250r axle and used the crfx spacers and odo drive...so I GUESS they are interchangeable...Im not 100% positive though. so buyer beware. jejeje

Edited by elsalvadorXR6

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I think 2004 was the first year of the new caliper bracket.  I know that my 2005 forks have the new style.  But using the later years forks isn't a problem other than sourcing the newer bracket, which slides right on without even disassembling the caliper.

 

2003+ forks have the larger diameter base vavle, so are more tuneable than the earlier forks.  But any would be much better than stock forks.

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