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So I have a 1992 SR with USD forks. I assume they're the same as the 93-94 E model USD forks... I finally got a chance to take the bike out for a spin last weekend (first proper ride since I bought it). Rode fine, but I agree that stock suspension is too soft. In very bumpy stuff it was somewhat unstable and I was being thrown all over. I'm 180-185lbs without any riding gear (so maybe 195-200 in gear). Anyways, after that ride, I've narrowed my next purchases to two things: a set of taller bars (RC High) and some racetech springs (0.42). The rear suspension felt alright. Well, ok for now I guess, not as noticeable as the front. Front would be ok for most of my riding, but I can make the front suspension go down with one hand... I'd say that's pretty soft.

It seems like OEM cycle have the cheapest price (even beat Amazon!):
http://www.oemcycle.com/Item/product/900013004

As far as I understand, this is the only option for USD forks, correct? Is putting these springs in pretty hassle-free? I understand the preload spacer needs to be removed as the springs are longer than the stock ones. Is there anything else to it? Any recommendations on oil weight/quantity? I always thought most stock USD forks from various OEM makes had the same diameter, but that just shows how little I know about suspension. Just want to confirm it's a sure-fit and fairly hassle-free installation. I know a set of KX forks would be best (as they only cost a bit more than RT springs), but I think it would be too much of a hassle for me.

Oh, and a final question/comment: I found the front end to be a bit low compared to the rear. This despite having raised the front suspension up to max. The rear still has maybe 2cm to go up so I don't think the angle is off. Maybe it's the seat though... I'm not used to those curved seats. Seems like I'm always sliding forward when sitting down. Felt a bit strange at first but I got used to it. Thank god I had some risers though!

There are no preload spacers inside the 1993 - 1994 USA KDX200 USD forks. It is a little more complicated than the conventional forks, but not too difficult. If you are OK with dealing with the KIPS valves, then the forks are not that much more involved.

Go with 5 weight oil. Since the inner fork tubes are only 41mm, only one liter of oil is needed to do both tubes.

Thanks. So 500ml each? If there are no preload spacers, I guess it means the spring just slides in with no additional mods?

My builder said 7 wt oil, but riding styles will change your opinion on that. I also have a hard time believing that .42s are enough spring for a 185# rider.
I have 93 USD forks, had them built for fast whoops and dessert, 160# rider, .41 springs, 7 wt oil. I am now at 180# and the springs are, noticeably, too light for me. I think that Racetech's calculator is a little off for these forks, so consider going a tad higher than they recommend.
Here is what there calculator said about me (and I am no A dirt rider);
odifiers:
Riding Type: Desert
Age: 30-44 Years Old
Skill Level: Dirt Intermediate/Expert/A Class
Height: Standard Height
Gas Tank: Standard Gas Tank

FRONT FORK SPRINGS
Recommended Fork Spring Rate: 0.41 kg/mm (use closest available)


So at 185, I would use there calculator for a "dessert rider" or "motocross" in A class.

Thanks 6, that's just the response I was hoping for. I'm really unsure as I get between .423-.446 depending on what I input. I certainly don't want the forks to be too stiff, but I wasn't sure about getting .44 or .42. Now I think I'll go ahead with .44. Thanks for the input. Though I don't jump, I do a lot of tight trails but also quite a bit of fast straight slightly bumpy trails (3rd-4th gear). A few things to consider which probably add to your opinion:
1-My bike weighs probably a tad more than the E series (it's an SR)
2-I'm tall ("tall rider" category)
3-I figure I can "grow" into stiffer suspension as I get better with a smoker
4-If I pack on a few lbs it won't matter...

One thing I find really weird is why they want a person's weight without riding gear... Wouldn't it make more sense to get a rider's TOTAL weight? I mean, some people's riding gear weighs little more than 5-6lbs (light boots, knee and elbow pads), while other's add a good 15-20lbs in extra gear/tools. I often bring a daypack so that alone ads a good 5-10lbs on top of my boots and helmet (~7lbs?).

Bitteeinit wrote: One thing I find really weird is why they want a person's weight without riding gear... Wouldn't it make more sense to get a rider's TOTAL weight? I mean, some people's riding gear weighs little more than 5-6lbs (light boots, knee and elbow pads), while other's add a good 15-20lbs in extra gear/tools. I often bring a daypack so that alone ads a good 5-10lbs on top of my boots and helmet (~7lbs?).

Nope...and the reason why is...people seriously over judge how much there gear actually weighs. The guy that "built" my forks asked me very specifically what type of gear that I wear, such as a tool bag......That's why an MX/supercross riders springs would be lighter...they don't wear that gear/tool bag.

Fair enough. But either way, you have .41 and weigh 180 and you think they're too soft right? I assume .41 were fine when you weighed 160? Either way I'll go for .44. Seems to make sense. Both are probably ok for my weight, but I'm pretty think now so I doubt I'll lose any weight.

No, I had .41 @ 160...NOW I weigh in at 180 (I know my wife tells me all the time).....and that 20# difference is HUGE....go with the .44 or (if you are a fast rider...again I am not) the .46....

Go for .44.

It is NOT 500mL per tube. My main joy was having to only use one bottle of fork oil instead of having to open a second one. One bottle can do both tubes, as the quantity is not over 500mL.

Hey Jason, how much oil did you put in each tube? You say it's "not" 500ml/tube, but above that you mentioned using 1L for both... Or do you mean one only needs a 500ml bottle (and put 250ml in each)? I just had the new springs installed by my mechanic and they told me they put 500ml in each... New springs felt soft at first, till I puched down hard and then sat on it and realized it was mostly sag. After test riding a bit going up and down sidewalk curbs, they feel hard, but I'll have to test them out on a proper offroad ride (which will be tomorrow!). Not sure what weight they used. I'll go ask tomorrow before leaving. It would suck if they put in too much oil as it's a pain to take it out...


As per this picture, the springs came with a metal tube and "washers".
[img[http://s27.postimg.org/820ubjj83/Screen ... _22_24.png[/img]

How much (or what length) if any preload did you use? I noticed my preload "bar" was not returned (along with my old handlebars and old springs. Also missing is the instructions manual)... Maybe they just left the preload bar there, or maybe they put in a bit and left the rest... Either way, I'm curious (and a bit worried). Sag seems almost identical to what it was before the new springs were put in. The racetech springs are obviously slightly longer than the stock springs, so I assume preload would be much shorter. I think I remember you saying that no preload was needed, but I can't seem to find the post now. Anyways, I'm kind of worried they might ave gone full retard on it so I'll go ask them tomorrow to see if it matches what you say...

[EDIT]Just noticed this post where you say preload was about right (maybe a bit less).
http://www.kdxrider.net/forums/viewtopi ... 47#p151234

I think I'll do a sag test this Sunday to get an idea of how my rear is doing (always feels a bit low/soft). Either way, I'll try out the new springs in "real world" conditions tomorrow.

The fork oil I used came in 1 L bottles. I could do 2 fork legs with one bottle. It did not take the entire bottle. I can't remember how much went in each leg, but it was a little less than 50mL.

No preload spacers are needed on the USA 1993 - 1994 forks when using the Race Tech 3647 springs. I want to say they gave about 10mm of preload, which is what they preached years ago, but now they recommend 4mm.

Thanks Jason... Those guys put in a little bit of preload (hard to judge from the remaining piece, but maybe 3-4cm). Kind of worried me after reading your advice but I took the bike for its first real ride (6 hours). Preload or not, man oh man those springs are great! I can always take that preload out later, but those springs (as installed) make a world of difference indeed. I was worried the .44 might be too stiff but if anything, they allow me to go faster pretty much everywhere! I'm also pretty used to the 2-stroke feel now. I'll update with some pictures in the profile section when I get back home. But just wanted to say I'm glad I invested in some nice springs. Thanks for your help.

Hey. I am glad it worked out for you. Good job.

Out of curiosity, what would that unnecessary preload cause? Does it make the bike bounce back up faster? Does it make the shocks harder? What exactly would be the result of having it? It took time and money to put those shocks in, so I won't have them take them out just now, but down the line, I figure I'll have them take them out just to see if there's a big difference without them. Handling is still way better than it used to be, but if things could be even better...

harsher on very small bumps

geometry of the bike, as it is supposed to sag a certain amount

for now, enjoy the benefits it offers, then fine tune later