Front suspension too hard...that's make a change!

[COMBEN]

I'm a tad confused at the moment and please forgive my ignorance if this has been mentioned before but I couldn't find a post similar to mine...the other way 'round but not this way!
With my newly aquired 220R 03 I'm now getting up to speed and have noticed something I can't quite get my head around but then I'm no suspension guru!
I went to a tame MX track last weekend and confirmed what I notice on the trails when gassing her in the top gears... it seems that the compression of the front forks seems way too hard/harsh/slow to react but everyone else seems to whinge about the front springs being too soft...I like the softness but hate the harshness...are KDX's 'under-sprung and over-damped' from new? Although the bike has soft springing it just seems that the front can't cope with the faster, even fast 3rd gear small stutters without me getting beaten up, I even notice this when at speed on the front with the front jiggling even on small road ripples! Front end grip was never a problem and could steer on the end on the faster corners, just sat on the tank and all was fine. I could never say the ride was plush at either end though
I had the comp' clickers set to the middle and set them 4 clicks harder for the MX jumps after a couple of hours to 'firm up' the front end for jumps and boy it seems far far worse with only a few clicks...they sure are sensitive...setting them softer just made the front a too 'wooly' if you get my drift so something is happening in there!
She has the factory fork oil the bike came with, it may be old but has travelled only 600 miles...yes I know I should change this and will today.

Is this normal, do I have a problem, I'm wondering if my oil has turned into grease or something......my rear end (excuse the pun) is just fine and sweet, I can brake slide the rear around on thight corners, brake hard into deep bumpy corners (all I can hear is the stand flapping around though!) nail her over fast stutters and my rear never got bent out of of shape, really planted...I seem to have the oppsite probems to everyone else! I'm 5' 10" and 12 stone dripping wet!

cheers for any help, appogies if this has been mentioned before and I just need to upgrade to 'Gold Valves' or something?

Richard

 

[yo its matt!]

do a search i remember someone saying something about removing a couple shims on the compression stack on a kdx, if thats all thats needed i wouldnt waste my money on gold valves.

 

[kmccune]

Unless tou weigh nothing or are not getting out of first gear ;) my guess is that the previous ower changed the springs already.

 

[dirt bike dave]

Every KDX I've owned was too stiff on high speed compression damping and too soft on the springs. It's practically a KDX trademark.

This is bad because the springs are so soft, the bike can't handle big jumps and whoops. But with too much high speed compression damping, the bike is harsh on rocks and roots and sharp stutter bumps. It's only plush when you need it to be stiff, and it's stiff when you want it to be plush. Not good.

No matter how soft the springs are, a fork will not react well to rapid hits if it has too much high speed compression damping.

IMO, the best cure is to reduce high speed damping and stiffen the springs.

 

[kdennan]

I have only started tweaking my forks, but I already have noticed a huge improvement just by switching to Fredette Racing, .38kg springs, stock spacer length (90mm) and Race Tech 2.5-5wt oil set a 100mm from the top. Since your riding tracks you may opt to change your preload and your oil level. I ride technical New England woods and love the changes I've done thus far.
Cheers!

 

[COMBEN]

thanks thus far guys

cheers :cool:

thanks for the input you guys have confirmed what I guessed maybe the problem.... this soft sprung front end also makes my bike feel wooden and a lil' heavy it spoils what is a fairly light enduro bike, even by modern standards. Don't get me wrong maybe I'm picky, I'm still pleased and quite honestly amazed at how capable and 'multi-tasking' she is...down to gym on the road in style and fun with the front wheel popping off the black stuff, both grunty, useable and quick on the trails and a hoot on the MX track..... not sure what else would that, my mates CRF250 enduro does a good job too but boy has he had some major engine problems with that bike :(

To answer the query regarding the question of aftermarket front springs, I know 100% that this bike is 'as factory built'. The only caveat is that when I started my first ride 'tweaking' the sag was set way too high and all (front and back) clickers were set to the hardest setting as if set for a heavyer rider. The previous owner whom is known to me and 10.5 stone bought the bike new and unbuilt (but shop built after purchase) as a pit bike, his 8 year old son rode MX.
I do know that the bike is a US market model and was not a euro 220R as it has twin filament light rear end, front brake light switch, different wiring loom but is 110% not a grey Jap' SR import. I feel sure that spring settings would be the same world-wide as KDX's were sold into nearly every market I can think of, unless anyone knows different!

...just a thought as you fall asleep and dream of your ride tomorrow (or that night!) and this may sound crazy but please bear with me on this one..........
would a thinner oil ( :yikes: ) but more of it increase lower speed (mph) compression rate (soften it) with not make too much difference to the rebound and firm up the front end when getting in the big hit lower fork (full deflection) strokes...like I said, I do like the soft front end as I like a bit of comfort as my age befits, and faster jumps would be handled by the rear end which to my ass feels real planted, solid and sweet and so controllable, it's only those slow 3ft+ drop offs where the bike doesn't so much glide down to terra firm but 'plonk' down (couldn't think of better word?) that make this idea fall down....like I said I'm only thinking out loud on this one but would like a another view, and don't hang back!

thanks for your help guys

Richard

 

[dirt bike dave]

Oil weight mainly influences rebound damping so I don't think you will see too much change in your compression damping..

Oil height controls bottoming resistance and by raising it you can stiffen the last bit of travel.

IMO, the only effective way to reduce high speed compression damping is to revalve the forks.

 

[Rhodester]

I put in Gold valves and stiffer springs. Even with the Gold valves set at a middle of the road high speed compression setting it was still too harsh. I ended up with a 2 stage stack with the low speed compression in a middle of the road configuration and the high speed compression on the lowest recommended stack configuration. Now it's pretty good. Be careful about thinning your oil too much or you'll reduce your rebound damping too much. I run 7 1/2 weight in mine.

 

[QLD_KDX]

I revalved my forks by removing two of the shims from the shim stack in the bottom of the fork. It made a world of difference to the handling, mainly it improved that harshness you feel when you hit rocks, roots or stutters.
I posted details of how to do this...do a search for 'shims' and you should find it. A lot of people have tried it for themselves and have good reports. And best of all, it's relatively easy, and it's FREE!.

Youll also appreciate it if you put stiffer springs in as well - I am 80 kg and I used .41 Eibach springs to suit an XR400 (they are longer so you can use a shorter spacer when you set your preload)

Hope this helps,

Andrew

 

[matt-itude]

Im 235 removed the 2 shims and installed 44 springs. huge difference. very confidence inspiring.

 

[tptp]

I am 75 kg, changed from stock to .42 springs, they were longer so I took 10mm of from the spacers to get 15mm preload, removed two shims and 100mm airspace with 5W oil. It works much better.
Before the front tipped forward and it bottomed out very easy, main movement was very low. I got it on video and it looks just strange.
After the change I have no problem and just need to adjust the compression klicker due to if it is hard or soft/muddy.
Try it!
Search for shims and good luck!