w/o RAD valve, mid-range hit is much stronger

[CMcCarthy]

In an attempt to calm my psychopathic KDX down and give it some more low-end, I removed my RAD valve and replaced it with the stock cage and reeds of unknown manufacture. Now, it hits like a freight train in the middle revs. It will snatch the front end up very violently in 3rd gear at will. :scream: It did this with the RAD, but not nearly as bad. Frankly, I thought the RAD was causing it, but it appears as though it was actually DECREASING the hit. It has a torque pipe, not a rev pipe, yet it hits like a tweaked KX250. If I pin it going up a decent hill, i'm going over backwards for sure. What do I do now? I need low end torque.

 

[BucKat]

Do a search on needle jets.
I had the same problem and ended up replacing the needle with a BGK from Sudco. Made a huge difference. Tamed the mid hit alot making the bike a lot more fun and controllable. This set up may not be for everyone but it worked for me.

I eventually went and bought a 01 KDX220 and love it. Ya sure it lacks top end but hey,,,,I'm still alive. The 90 was too much for me.
I ride woods mainly.
'90 KDX
FMF pipe and silencer
Boyseen reeds
lid removed
torque ring in exhaust
reed spacer
162 main
42 pilot with a/s 1 1/2 out
BGK needle at #2 clip position

Good luck
Joe

 

[BucKat]

Oh ya! The torque ring was actually 2 cooper exhaust gaskets and I trippled up on the reed gaskets instead of dishing out a wack of cash for both.
It 'did' indeed increase the bottem end a very noticable amount.
Joe

 

[70 marlin]

the BEL needle will tame it for ya. I went for bigger hit with the CEL. read this thread. it will help big time with needle selection and jetting! http://www.dirtrider.net/forums3/showthread.php?s=&threadid=43334