I was just reading the new post about 1st mods to install. I am interested about the xr400 springs can someone give me more info or tell me where to go on the website to get more info. I looked around but did not find anything. Sorry I'm new to the site.
I bought some a few months ago from servicehonda.com (I think that's the site). $88 shipped. They not only have a firmer bottoming resistance, but the first little bit of travel is actually more plush, due to the fact that the longer spring replaces the useless Kawi spacer. I bought the .42 springs but wish i had bought the .45 springs. After the fact, I'm sure the .45's wouldn't be too firm. I'm 200lbs. and ride some very rocky stuff. I also used 7wt. fork oil. I forget the oil level now.... around 5mm of preload. I didn't know anything about it when I tore it apart. It realy is an easy job. Go for it.
Honda only makes .38kg springs (earlier XR400 models) or .40kg springs (later models). I bought .43kg Eibach springs (for XR400) and run 3mm of preload. They are perfect for my riding style and 225lbs. I would not go any stiffer (for me) unless I was doing sky shots (ie. big jumps) all of the time. I run Gold Valves and 7wt oil. I run the GVs with a 2-stage valve stack. Until recently I ran a cL8 (fairly heavy) low speed compression stack and a cH3 (fairly light) high speed compression stack. I just made the change to a cL6 and a cH1 looking for a little more plushness (haven't ridden it yet with the new settings). To be honest I've never ridden a KDX with the stock valving so I really don't know if heavier springs for my weight would work well or not. How much do you weigh and how aggressive is your riding style? What kind of terrain will you be riding in?
XRIowa, the stock KDX front springs are too soft for all but the lightest riders. The springs from certain model XR400s are a perfect upgrade. Search this forum - there is a ton of info on this upgrade.
Alright the springs I have in my XR are Eibachs set to my weight right around 220.. I like the softness of my KDX suspension but I feel it may get old quick... Just kinda new on the KDX and loving the lightness nimbleness of it compared to my XR!! I will try the swap I am not sure what is in the KDX right now but if this works it would be great... BTAW would'nt it unbalance the suspension to set up the front so much stiffer and not do anything with the back??? Does the XR rear shock spring work on the KDX as well???
The KDX comes pre-unbalanced from the factory for you at no extra charge. The rear seems good for a 180 lb. rider and the front is more for a 130 lb. person.
I had the .4kg springs in but swapped it with the .38kg's.
My weight is 80kg & find the .38kg much better in the rocky sections. Preload 4mm with 7.5w oil @ 100mm & clickers 10out.
Again, all depends on your riding style & terrain.
FRP = Fredette Racing Products (Jeff Fredette, world famous KDX racer).
The 5.0kg stock rear spring is just right for my 225lbs. I tried a 5.2 Eibach and it was way too stiff for my riding style (with FRP shock valving, 7wt. oil).
I got .43 Eibachs for mine, but in retrospect I should have got the .41's. I am 80kg and found I had to slacken off the clickers and increase preload on the rear to balance it properly. Also, I guess I'm not as fast or aggressive as I used to be, so it's a little stiff for me now.
Just the same, it's not bad, and i'd recommend it to anyone. Just do your research on the correct spring for your weight and riding style, and you can't go wrong.