Jetting Help

Joined
Oct 22, 2003
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#1
I bought a brand new 2002 KDX 220. After a couple trips to the desert, I figured out this is a woods bike and not an open plains runner (no top end at all- I mean ZERO). Well now things are gonna change. Here is what I have done to my otherwise stock bike: Tossed the snorkle, tripled the size of the remaining airbox lid opening, installed a UNI high flow filter, had the 33mm carb/slide bored and reworked to 36mm by RB Designs, installed Carbon Tech carbon fiber low tension reeds, installed FMF Gnarly Rev pipe w/stock silencer. I figure all that stuff ought to do something but it remains to be seen. My final big question is what jets to run. Has anybody out there jetted there bike with the RB Designs Carb? Canadian Dave says given the mods I have to jet it identical to a late model KDX 200 (#160 Main, #48 Pilot). RB Designs sent the carb back with a #152 Main and #40 Pilot. Of coarse it has a divider plate with the slide and circuit reworked. So I could use some advice. I ride at sea level (Ocotillo Wells) in really warm weather and would rather run a scosh on the rich side.
 

Canadian Dave

Super Power AssClown
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Apr 28, 1999
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#2
Give Ron's jetting a try. He will have installed a different jet needle as well. There has been a great deal of work done on jetting these carbs for KDXs and Ron is well informed about what does and doesn't work. I have every reason to believe that your new carb will run well as delivered or only need minor adjustments with the jetting that's in it now.

If you're looking for more speed in the desert you may also consider a smaller rear sprocket. You should have the power to pull it now no problem.

David
 
Joined
Oct 22, 2003
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#3
Thanks Dave. I got the carb back today. Ron replaced the main, pilot and the the needle! The carb is starting to look like art-work, that divider plate looks so sweet with the polished bore. He also gave some jetting advice and you're right- he knows I ride sea level and has it dialed in very close- maybe perfect. I can't wait to try the bike out with all the changes. Hopefully next weekend!

John
 
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Apr 22, 2003
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#4
Lizard Lips....

You have alot of mods going on there. I think you might want to consider changing out the OEM piston. There are lots of threads regarding failure of the stock 220 piston with heavily modified bikes.

Would be a bummer to blow the sucker up now.
 
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Oct 22, 2003
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#5
Well at least I'll have a huge grin on my face until she does blow! Seriously though, I hear ya, but I just want to see what a difference all this makes before I consider going into the motor. Right now it still has a stock low compression head and untouched cylinder, so I'm hoping I can live with it like this for a while. I don't race, I just want to go out there and enjoy the snappiness of a good running 2-stroke in a lightweight comfortable frame. And run down a few lizards while I'm at it. (I chased a big one down a sand wash for about 75 feet before he darted under a bolder last June!). Does anyone know how I can change the dumb United Arab Emirates flag that I'm stuck with? I meant to pick USA.
 
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Apr 19, 2003
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#6
pick your cp, then pick edit profile. your cp option should be at the very top of a page like this one.