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Re: What rear shock spring rate?
Posted: 11:36 am Aug 14 2014
by KDXGarage
5.8 on a 1992 model?? Surely not. Check your sag with whatever is on there now.
In the USA, 1989 - 1994 fork springs are .30. Look at Kawasaki's website.
Re: What rear shock spring rate?
Posted: 01:15 pm Aug 14 2014
by robkdx
Jason wrote:5.8 on a 1992 model?? Surely not. Check your sag with whatever is on there now.
In the USA, 1989 - 1994 fork springs are .30. Look at Kawasaki's website.
Not sure where you got im on a 92, in my first post I said I have an 06.
Re: What rear shock spring rate?
Posted: 04:15 pm Aug 14 2014
by KDXGarage
Sorry. I thought it was Biteennit 's reply.
Re: What rear shock spring rate?
Posted: 09:18 pm Aug 14 2014
by Bitteeinit
Jason wrote:Thanks for updating your location profile. I keep meaning to type up some thoughtful new thread to encourage everyone to post his country, as some models (like yours and the forks) are different and mot people on here are in the USA and just think about the USA bikes and what characteristics the USA bikes had. I had no clue the G?? model had USD forks back in 1992 until I looked up the frame number for you.
The Honda XR fork springs WILL NOT work in "what we in the USA call 1993 - 1994 USD forks". I used to have a paying hobby suspension service and test fit various springs in the 1993 - 1994 USA USD forks. Race Tech 3647 model is THE BEST choice of all the springs I tried / used. Race Tech and FRP Offroad are the ONLY aftermarket springs that I found to work.
The preload length was about right, as far as I remember. Current preload amounts are a little less than a few years back (4mm instead of 10mm on the Race Tech site), but they are still the best option.
USA Honda XR250 springs were too short, as best I remember. Check spring length before taking a chance.
In the USA, the 1989 - 1994 springs are .30Kg/mm rate. Basically, ball point pen springs.
On the rear spring, 1989+ sprigs are all interchangeable. Drive over to the house, and I will give you one.
I know.
What is the actual weight of your bike? I am only used to spring rates on the 233 pound E models. If your bike has the steel tank, blinkers, speedometer, etc., (can't remember if they were still on or not), then it may be a touch heavier.
In the USA, the stock 1989 - 1994 "E" model KDX200 shock spring is a 4.6 Kg/mm rate. Assuming your swingarm, linkage and such does not cause a different need, then a 4.8 rate may be what you need.
*******and Cannon Racecraft***************** (just saw 6riders post)
Once again, thank you for a very informative reply. Would you say getting new springs is as good as getting KX forks? Or the next best thing?
I got excited thinking I could use stock XR400 springs, but then I saw that you say these WILL NOT fit. The Race Tech springs come with with different preload spacers if I understand correctly so adjusting preload/sag shouldn't be a problem?
I'll have to check the weight of my bike to be honest. The blinkers and footpegs have been taken off. I have a plastic tank (so someone removed the metal one). Pretty sure it weighs virtually the same as an E-series, but for shits and giggles and when the time comes, I'll try to balance it on a scale to get an idea of the wet weight (minus gas). According to Race Tech, I would need .44 springs. It varies from 42.6 or so (180lbs) to 44.2 depending on the stats I put (185-190 TALL RIDER). So I might go for .44 since the bike probably weighs a tiny bit more and in case I gain a bit of weight, though I also don't want the ride to be too hard. If I ride a lot of bumpy terrain, is it better to get softer suspension?
As for the rear shocks, that makes it easy! Seems like KDX's also have interchangeable rear shocks? Race Tech shocks seem to be compatible with many different makes/models (SRSP 622850)... Do you recommend changing the rear shocks or are the OEM ok? You say the OEM are 4.6 Kg/mm and that 4.8 would be ok (so slighly stiffer). But here is what Race Tech recommends:
REAR SHOCK SPRINGS
Recommended Shock Spring Rate: 5.1 kg/mm (use closest available)
Stock Shock Spring Rate: 4.6 kg/mm (stock)
FRONT FORK SPRINGS
Recommended Fork Spring Rate: 0.442 kg/mm (use closest available)
Stock Fork Spring Rate: 0.296 kg/mm(stock)
Is 5.0 too stiff? Would 4.6 be better? I've never used aftermarket suspension before (I usually just get used to what stock offers me, lol). I ride through everything: fast straight/slightly bumpy lines, very rocky terrain (sometimes), some mud but usually hard bumpy surfaces (some big dips).
Re: What rear shock spring rate?
Posted: 11:05 pm Aug 14 2014
by 6 Riders
IMO for "Bumpy" soft is better. I noticed on Racetechs site, that MX uses a softer fork spring than trail, must be for landing the table tops?
THERE is nothing that you can do to a KDX fork that will make it even close to what a KX fork is. BUT, for trail riding at slower (not pinned in 3rd/4th gear) paces, the stock KDX fork with good springs and proper oil viscosity and level will do you just fine. I don't have a problem with my 93 forks until I hit speeds on the trail and braking bumps get a little tiring.
Re: What rear shock spring rate?
Posted: 04:11 am Aug 15 2014
by KDXGarage
biteeinit, I would think .42 and a 4.8.
The shock springs fit a lot of bikes. The shock itself does not.
Re: What rear shock spring rate?
Posted: 10:01 am Aug 22 2014
by Bitteeinit
A quick bump here. Looking at the Fredette site, it seems he recommends a 0.38KG spring for anyone 150-200lbs... Racetech recommends 0.42. Why is there such a big difference? Are .42s going to be ridiculously hard (geared towards jumps and the likes)? I can't even find .38 racetechs... Is Fredette talking about a different brand (though spring rates should be the same, no?).
http://www.frpoffroad.com/aboutus.htm
Re: What rear shock spring rate?
Posted: 11:54 am Aug 22 2014
by KDXGarage
His spring rates may include the stock amount of preload from 20 - 25 years ago thinking on preload. Modern preload is small. The springs carry the weight of the bike and rider at the correct height. Valving will control jumping vs. putting through an easy trail.
Re: What rear shock spring rate?
Posted: 05:39 pm Aug 22 2014
by robkdx
After running .42 and 5.8 last weekend I recommend them for a 220lb rider. Woot! What a change.
Different bike. So much more stable. Yes I did change to KX125 forks. May need to reduce shims on the mid stack as it deflects off roots a bit.
Re: What rear shock spring rate?
Posted: 09:33 pm Aug 22 2014
by 6 Riders
If you play with Racetech's spring estimator a bit, you will see that if you are riding motocross, the rate goes down (softer). Anyways, I had my forks built for me...I was 160# and had him set them up for a "B" rider in dessert terrain....He put .41 springs in and I would say that they are perfect. I think that Fredette is a just little on the light side for NON-racers.
Re: What rear shock spring rate?
Posted: 10:26 am Aug 23 2014
by Bitteeinit
Thanks all. Seems .42kg is good. If I don't like them I'll just sell them to someone with an XR400...
Jason wrote:His spring rates may include the stock amount of preload from 20 - 25 years ago thinking on preload. Modern preload is small. The springs carry the weight of the bike and rider at the correct height. Valving will control jumping vs. putting through an easy trail.
Cool. Did you ever get gold valves for your USDs? I don't think upgrading to KX forks or getting new valves would make a big difference in my case. I'm getting the bike parts next week (a guy is bringing them over... Been waiting almost a month). Next weekend I'm finally going to take it for a long ride and see how it feels. If I really hate the shocks, then I'll order those springs ASAP. Might wait out on the rear spring if I like it. Can't wait...