Gold Valve in Rear Shock --Has Anyone...?

Robcolo

Member
Jan 28, 2002
342
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I'm still having a serious problem with my shock even after a revalve and lighter spring. The rear end will kick violently sideways -probably 30 -40 deg out - after encountering certain rocks. This happens 2-3 tiimes during a days ride and will eventually result in a get-off. I'm thinking it's the old "Yamahop" or hydraulic lock when the stock piston can't pass oil fast enough on a high speed hit. Has anyone else noticed this and did the Gold Valve with it's large oil ports cure it? They've certainly solved that problem in my front forks.
 

jmutiger

Member
Oct 10, 2001
169
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I have some other suggestions...

First make sure your front forks are as low in the clamps as they will go, this will stabilize the bike.

Second, try cranking up the compression on the forks, this will keep the front end higher more often, again resulting in a more stable ride.

Third.. What air pressure are you running? The tire is a spring in series with the damper.

Fourth.. Back off your compression adjuster all the way on the rear shock, this will open the orifice to allow what would most likely be described as low speed flow. Then from that point try playing with your rebound adjuster.. As you may or may not be aware, the rebound adjuster controls a "bleed" which affects both compression and rebound. The proportion of this effect is due to the shims.. So if you've played with your valving spec on the piston, chances are your rebound adjuster is affecting your compression just as much as rebound. Generally speaking, on a dyno the compression is very soft in comparison to the rebound (peak forces).

Personally, I can't see you or any of reaching the point of all of the piston orificed being used to the fullest capacity. UNLESS you've toyed with your shim stack, and have reduced the amount of space the shims have to bend to their stop, known as a stop plate.

On a side note.. You are riding a KDX, and it has limitations, especially in the suspension dept. I've experienced Yamahop first hand, on a factory WR426.. it wasn't pretty.. I can say with full belief that the KDX doesn't have the same kind of throwing the rider into the woods power.

Anyway.. that's my 2 cents worth.

Jon!
 

acutemp

LIFETIME SPONSOR
Sep 4, 1999
197
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Rob,
I have installed the RT gold valve along with a 4.8 spring on my KDX. I'm very pleased with the results as it is much more plush than the stock setup.

Do you know what the shimstack is that you are running with your stock piston? You might be able to do some adjusting to this that might help with your deflection problem.

I had problems with the forks packing down on consecutive hits while working with 2 stage stacks in the front GV's. I finally settled on a single stage setup that tends to help keep the front end up in it's stroke while not being harsh.

Good luck--Dan
 

Robcolo

Member
Jan 28, 2002
342
0
Jon & Dan -- Thanks much for the thought and suggestions. Part of the problem IS tire pressure. Even with Moose super heavy tubes, due to the abundance of really sharp rocks & ledges where I ride I get rim cuts with any pressure below 16 front & rear. [But I run the same 16# in my KX tires and it doesn't kick like that ] I.ve also noticed the front end packing down a bit but attributed it to weak spring and/or not enough preload. I have a new set of .38s from Fredette waitig to be installed. Never thought that it might be the 2 stage valving. [ High speed 5 low speed 4 - Race Tech recommended shimstack] I'm guessing that the shock's shimstack is pretty close to stock as my guy doesn't change things by very much.
 
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