KDX220 mods and jetting sugestions

grahams

Member
Sep 26, 2001
20
0
Hi guys. I've owned my '01 KDX220 for a few years now, and the time has come for the next level of riding (and mods ;)).

I have ordered a set of Racetech .44kg springs, an FMF Gnarly Desert Pipe, Powercore II silancer, and a set of Boyesen Power Reeds (#607). I will also remove the airbox lid.

I live in Johannesburg, South Africa, at 5000feet, average temp is 26 deg. centigrade or so.

Could anyone give me base line jetting for the above mods?
 

Red_Chili

Member
Nov 30, 2005
79
0
May not be stiff for your weight, depends on whether you ride the tight stuff or the fast stuff. Also depends on whether you are doing any valve rework in the forks.

As far as jetting, I have a Gnarly Desert with stock silencer, and live at 5280 ft., riding to 8-9000 ft. I am starting with a 140 main (bought the bike totally stock with a 142, and it was SPLOOGY rich - had good success with a 138, ran cleanly prior to the pipe change) and stock needle on 2nd from top clip. I may need to move the clip to the middle, maybe not. Seems pretty good for now, but it's not hot here right now so that may change. But it is a start. The pipe might want a richer main than what you were running before, by an increment or two.
 

grahams

Member
Sep 26, 2001
20
0
Red_Chili said:
May not be stiff for your weight, depends on whether you ride the tight stuff or the fast stuff. Also depends on whether you are doing any valve rework in the forks.

As far as jetting, I have a Gnarly Desert with stock silencer, and live at 5280 ft., riding to 8-9000 ft. I am starting with a 140 main (bought the bike totally stock with a 142, and it was SPLOOGY rich - had good success with a 138, ran cleanly prior to the pipe change) and stock needle on 2nd from top clip. I may need to move the clip to the middle, maybe not. Seems pretty good for now, but it's not hot here right now so that may change. But it is a start. The pipe might want a richer main than what you were running before, by an increment or two.

Thanks for the reply. My bike is totally stock and it's running a 148! But I suspect it's very rich at the moment.

I'll start with a 145 and do a few plug chops to see what's up. Are you still running the 42 pilot?
 

Red_Chili

Member
Nov 30, 2005
79
0
To be honest, I do not know which pilot I am running. I suspect it is not stock. The bike was rejetted for our altitude *sort of*, though the main was still way rich and the needle in the middle didn't run optimally either. The pilot air screw is well within range and idles cleanly and blips clean off the bottom, so I took the approach of "if it ain't broke don't fix it".

I suppose I am glad it was rich, as the prior owner never changed the piston and it showed scarring. But I sure had a lot of carbon to clean out of the KIPS.

If you are at 5Kft., a 145 is gonna be way rich STILL, unless you are running an aftermarket pipe. Try a 140 for grins, and bracket it from there. Like I said, a 138 worked well before I put the FMF Gnarly on it.
 
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