KDXRIDER.NET

For future reference, Cannon Racecraft can make just about any spring you want- length, rate, progressive, etc.

http://www.cannonracecraft.com/

Honda OEM 0.40 Kg / mm XR400R fork springs, $47.13 each at Partzilla ($94.26, plus shipping). "FREE Shipping on orders of $149 or more"

Project update:
I rebuilt the forks with the 0.40 kg/mm Honda springs and 10mm of preload. I adjusted for sag, and the stock rear shock is borderline too stiff based on the numbers.

First ride:
I took my dad riding for his first time on this trip (he rented a mild bike and had never ridden off-road), so I was taking it really easy. The engine felt awesome. The RB Designs carb and head mod really waked the bike up, and my first top-end rebuild was a success. The bike starts on the first few kicks, has crisp throttle response, and more power than I need. The suspension felt balanced but stiff. Other than that, it didn't really stand out as feeling particularly good or bad.

Second ride:
This time I just went with a buddy (a novice riding a new 2018 Yamaha WR250F), so could let it rip. We met another rider (on a 2016 Yamaha YZ250x) who was faster than us (I'm intermediate level), so it was definitely a good test of the KDX suspension. I was very disappointed. I had to work pretty hard to keep up, and later swapped bikes with both guys. The WR (which is set up of for my 160lb weight) felt like a magic carpet ride! It was so easy to ride and more forgiving. It took much less precision in picking lines and in body position. The YZ (set for a 190lb rider) felt too stiff but still much, much better than the KDX. The heavier, experienced YZ rider commented that my bike took a lot of input to initiate a turn. The WR rider wanted his bike back pretty quickly. He said he felt more connected to my bike but that it was a lot harder to ride.

We then went to the drag strip, where the problems continued. Now some of this could be rider skill, but I just could not hook up off the line. The YZ would get me by about 4 bike lengths while my rear end thrashed around, but once I finally hooked up I'd pretty much stay with him. This was consistent over about 6 races, despite me trying to launch easy and get the right front to rear weight balance. I destroyed the WR, which felt slow (it is 100% stock). We swapped bikes, where I once again beat him on his own bike (he was intimidated by the KDX power and no doubt being very cautious).

The verdict:
Anyway, all this is to say I am not happy with the KDX suspension, or at least my current setup. I just put the stock 0.35 kg/mm springs back in the front (I think I really need 0.38 kg/mm springs, but cannot find any). With nothing but a quick lap around the block in my neighborhood to judge by, I have to say it feels waaay better. Not sure when I'll be able to ride next on trails to see what it really feels like. I took some pre-load off the rear shock, but probably need to drop the spring rate to match the front.

What next?:
I did a ton of research before buying my KDX220, and everything pointed to it being a perfect trail bike for me. However, maybe I am a better rider than I thought, or just appreciate a good suspension set up. Anyway, I think I basically have 3 options:

1) Stick with the stock front fork springs and get a softer rear spring (I am 158 lbs w/ no gear)
2) KX fork swap, softer rear spring
3) Sell the KDX and get a YZ250 or KTM 250 XC (though my budget will be limited to about $3k)

On the one hand, I just rebuilt the KDX and the power delivery is great. I spent a LOT of time wrenching on it, and still have one foot in the dog house as a result. While I enjoy working on bikes, I really don't have much spare time for another large project. It's tempting to stick with what I have, but I feel I may be outgrowing the stock suspension.

On the other hand, as I got into the rebuild (all suspension bearings, front forks, top end, brakes, etc.) I realized the previous owner neglected the bike. Point being that while I've pretty much fixed everything, the bike is just worn. Pegs are loose, kickstarter lever is ovaled out, etc. Buying another bike would give me the opportunity to really find a nice bike with low hours for the year, and I have much more experience with what to look out for.

What would you do?

Did you do anything to your shock? I didn't see anything done. If your kickstarter and pegs are worn out, etc., then I assume the shock was never touched. If the oil was not changed, then it is not going to work like it is supposed to.

Riding a 2018 model with modern technology, then comparing it to a 1994 era bike with possibly WAY past overdue shock oil, it won't be much of a comparison.

His bike cost around $8,000. What have you spent on your used, worn out KDX? Hell, I hope his feels better. I would feel much worse for him than you.

Good point about the rear shock, the internals have not been touched. I probably have about $2.5k into the KDX, not including my labor. But I could buy a freshly rebuilt '09 KTM 200 EX for $2.5k that is already set up for my exact weight. Tempting.

NCKDX wrote:Good point about the rear shock, the internals have not been touched. I probably have about $2.5k into the KDX, not including my labor. But I could buy a freshly rebuilt '09 KTM 200 EX for $2.5k that is already set up for my exact weight. Tempting.

How did you get to $2,500 in a KDX without touching the shock?

Good luck if you get the KTM.

I could see $2500 easily with what he has done. From your ride reports I think you have two choices, sell the bike and look for something newer or slap on a KX 125/250 front forks. Before you ever mount the forks, take them AND your rear shock to SR1 suspension in Taylorsville (just N of Charlotte).
Truth is if you do buy a newer bike, I’d still highly recommend you let SR1 do your suspension. Oh, yes, when you buy that later model bike, be prepared to replace all those bearings you just replaced in your KDX!