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I am very happy with the stock forks on my '04 KDX, but I would like to get a bit more rebound damping - without going to heavier oil (subsequently affecting the compression damping). There is a small hole at the top of the damper rod, which appeared to be the only orifice that regulates the rebound damping. Can anybody educate me on any other sytem components or ports that might affect the rebound damping characteristics of these forks?

gregp wrote: I would like to get a bit more rebound damping - without going to heavier oil (subsequently affecting the compression damping).

I believe that is why a lot of people install forks off of other motorcycles....

I am very happy with the stock forks on my '04 KDX

Now there's something you don't hear very often!

Not much you can do. The only way to adjust rebound on those forks is with oil weight. As you notice, there's no rebound adjustment present.

My neighbor just picked up a 95 that had the forks done by someone. He was told that one fork now controls rebound, and one controls compression. I asked him to show me the paperwork, and he said he has it. I'll see if I can get my hands on that and see what was done, might help you out.... I wouldn't hold my breath though. It sounded to me like a crock.

juliend wrote:

I am very happy with the stock forks on my '04 KDX

Now there's something you don't hear very often!

Well, I actually miss my stock forks! They were much better in the sand and the tight twisty stuff than my current stock KX forks. Once I get them re-valved though I'll probably think differently.

gregp, probably the best thing you can do is installing some Gold Valves. You could adjust your rebound with your fork oil and then tailor the Gold Valve for proper compression using that oil.

I wont' argue with that. When the trails get really rough and rocky, and the going is slow, I kind of miss my old forks too sometimes. They soaked all that stuff up instead of bouncing around like the mx forks do. The benefits much outweigh that though. I like being able to ride faster without fearing for my life, lol.

I would try a hevier weight oil, say 7 wght. It may not effect the compression damping in a bad way. If you are already in that weight range a revalve would be needed....

I found the KX forks (as well as CR suspension) needed to be revalved for the KDX. I fought it for a while but that is what I ended up doing in the end.

Thanks for all of the comments so far. I am not looking for the non-existant "adjustment". I am looking to make a modification to my fork damper rods, such as weld up the rebound port, and re-drill another one, in a smaller dimension.
I ride tight gnarly trails with high speed, sharp hits, and the stock forks really work fairly well. I have tried many different oil weights, and just want to custom tune them to my preferences.
To tell the truth, I have ridden many more recent bikes with USD forks, and most stock items do not work as well for me. I have ridden some bikes with modified forks (for Eastern conditions) from Factory Connection, C-Cycle, and more, and some work very well - but all that work well seem to have very minimal compression damping characteristics, with a significant increase in rebound.
At sme point, I may consider Gold Valves, or machining my own "large port" pistons, but for now, I just want to look into the increase in rebound damping. I have found that revalves help, but there is no overcoming restrictive ports when it comes to sharp hits.

juliend wrote:

I am very happy with the stock forks on my '04 KDX

My neighbor just picked up a 95 that had the forks done by someone. He was told that one fork now controls rebound, and one controls compression. I asked him to show me the paperwork, and he said he has it. I'll see if I can get my hands on that and see what was done, might help you out.... I wouldn't hold my breath though. It sounded to me like a crock.

That sounds very interesting. I am certain that it not as simple as flipping one base valve over, as the oil in that leg would need to bypass it during the compression stroke....

H series rebound adjuster "kits" can be found here:
http://www.racingsuspensionproducts.com ... vekit.html
It looks like the are installed inside the damper rod itself, and use YZ85 caps and rods... I am looking to accomplish the same thing, in a simpler, non-adjustable way.

I'm not a suspension expert my any means. I too enjoy the ride of my 05. It has gold valves in it. They were there when I bought the bike. I've ridden newer bikes with USD suspension. They do seem harsher to me although, I didn't get to ride them long enough to get comfortable with the bike and ride it at anny great speed on singletrack.

It sounds like you do a lot of riding like I do.

By "more rebound dampening" you mean you would like to slow down the rate at which the front forks "bouce back"...right? Can you explain why you would want that? Maybe it would be good for me too....

Do my gold valves offer rebound dampening?

Can you "dumb down" what the "kit" does? Would it work with my gold valves?

The extent of my suspension mods/knowledge are....the bike came with gold valves in it. I switched from 5 weight oil to 7.5 weight oil and liked the difference. I've wondered if I would like a heavier 10 weight oil.

Thanks....

This is all a matter of personal preference. Yes, I want to slow down the rate at which the forks extend. I want this because I run very light oil to reduce compression damping. In turn, this allows my forks to spring back up too fast, which can cause loss of control, or unintended wheelies.
I owned a KLX250 with Gold valves installed, but I never had them out to look at them (shame, really, laziness on my part), so I do not know if you could adjust the rebound damping with them by shuffleing the shim stack on the rebound side. By looking at them, I would guess "not very much". The biggest advantages of Gold Valves are the extra large compression ports, which means that they can blow off sharp, high speed hits more effectively. I believe that you will find the rebound ports slightly smaller, or very similar in area to the ports in the original valve, and it would not be externally adjustable at any rate.
Gold valves will allow you to run heavier oil than I do, increasing rebound damping, while still allowing a somewhat plush ride.
Gold valves are definately the way to go, but I am trying to find a "free" solution. I suspect that there is none, but that will not stop me from experimenting.

As far as the USD fork conversions go, the thing you gain is rigidity, and steering accuracy. You will still be restricted by compression port size in almost all stock MX forks. MX bikes are just not designed to hit the same types of things that trail riders hit. So, even with KX forks, I would most likely end up looking at doing the same thing (been there, done that - CR's and KTM's).

Best thing I ever did for my bike's handling was got up to 10w in the forks. Really slowed em down. I can now ride steep rocky or rooty sections that I used to get off and bulldog the bike through

Ah, this is exactly what I am after, Mr. Wibbens, except I want to use very thin oil and still obtain that result. I have worked on many cartridge design forks, but the KDX items are a bit primitive by comparison. Upon cursory examination, it did not appear that the cartridges themselves were easily disassembled for access to the cartridge piston. On the conventional cartridge forks on my old 1987 CR250, the cartridges were very similar, and the hole at the top of the inner cartridge rod was the orifice that regulated rebound flow. When I pumped the CR cartridge up and down, oil would come squirting out. I have not had the pleasure of having the oil squirt out of the upper hole in my KDX cartridges (all over my shirt), but I will take them apart and see what I can find out. It seems that it would be an easy process to weld up these little holes, and re-drill much smaller ones, to get the effect I am after, if they do indeed regulate rebound oil flow. I would also suspect that the piston inside the damper cartridge is a "rebound only" valve, much like the base valve is a "compression only" valve.

Good luck with it and please post up your results. You might just be on to the next "cheap" mod for the stock forks that others may benefit from.

The old school of thought on the stock KDX forks was to remove a few of the larger shims... now I have no idea why this is but people swore by it. Just throwing it out there for those why remember why or have done it.

Inda - I have already performed that mod - but all of the shims on our base valves are the same size and thickness. I did remove two of them, though (two from each side), with no discernable improvement to speak of.
I will let you all know what I find out by experimenting.

Mr. Wibbens wrote:Best thing I ever did for my bike's handling was got up to 10w in the forks. Really slowed em down. I can now ride steep rocky or rooty sections that I used to get off and bulldog the bike through

Alright Wibby....just drained the atf out of the forks and put in 10 weight. Riding singletrack Saturday. Hoping I'm like you and really like the 10

very interesting thread seems like the forks are everyones complaint.I am curious what is the weight of the factory fork oil? thanks

Pond Scum.... whatever that is.....