Jetting for FMF Gnarley/Turbine Core II

[Ga_KDX_Rider]

Sorry to beat a dead horse :bang: but I just installed an FMF Gnarly Pipe and Power Core II Silencer and I want to get the carb dialed in.

I have a 2003 KDX 200 and live in Northern Georgia.

I also purchased some Boyesen Power Reeds.


Can someone help me with this combination?

It looks like FMF's recommendation is to remove the airbox snorkel and keep the stock carb settings?

Certainly as long as the KDX has been around, someone has a proven configuration for this combination for maximum power delivery.

Thanks very much.

 

[Rhodester]

I'd start with a 155 main, 45 pilot, get rid of the snorkel, air screw at 1 1/2 out, needle clip in #3 and go from there.

 

[Ga_KDX_Rider]

Thanks...I was thinking along the same lines - just wanted a sanity check. I'll try that, then check the plug. I'd rather weigh on the rich side than too lean.

 

[Sandy Whoops]

I'm jetting a friend's '03 200 after installing a gnarly woods / TC II. Previously, he was using JustKDX' standard recipe for jetting (w/ airbox cover removed). After installing the pipe & silencer, we found the 45 pilot to be too rich and the R1174K needle too lean @ 1/4 to 1/2 throttle. We dropped to a 42 pilot and installed a BGN needle. The 42 pilot worked out well, but the BGN needle has a fairly hard hit. The BGN is a big improvement over the R1174K, though. The owner likes this setup, but I'm going to try some different needles to smooth out the hit.

Since you're in N. GA., your elevation may even require a 40 pilot. Suggest your order both a 40 & 42. Also suggest that you do some research on needles and order a spread of them from Sudco. Order any needed main jets at the same time. 4 needles and 4 jets will set you back about $40 at Sudco.

Remember that YMMV. There's no 1 perfect jetting setup. You're probably a couple of thousand feet above us, and you have to deal with steep clay hills.

 

[Ga_KDX_Rider]

I spoke with snother KDX'r and I think I'm going to try a 42/152.

With the power reeds it's suppose to run even richer, so I think this will get me closer in the ballpark.

SandyWhoops - I'm interested to hear more about the needles - did you find a happy place for the fuel/air screw?

So far I've got protaper bars on it with pro-grips, works connection frame guards/skid plate, fmf gnarley/tc II, power reeds and some neoprene forkskins coming - I hate the accordians!

I really appreciate everyone's input here.


When I'm dialed in, :ride: life will be sweet! :nod:

 

[Sandy Whoops]

I think the AS is about 1 3/4 out. I started at 1 1/2 and had to lean it out just a bit. With your altitude and a 42 pilot, you may need 2 - 2 1/2 turns out. If 2 1/2 turns or more is required, consider dropping to a 40 pilot. Somewhere around 2 1/2 turns, the AS begins to lose sensitivity. At 3 turns and beyond, changes to the AS seem to have no effect.

Plan to mess with the e-clip on the BGN next. Think we'll move it up a notch (3rd to 2nd) to bring the juice in a little later.

I think the 152 / 42 will be a good starting point for your altitude. Do a full throttle chop and check your plug. Don't get her too lean. Set the AS so you get clean throttle response when blipping the throttle from idle. Speaking of idle, you'll probably need to adjust it. Hold the throttle open a tiny bit while turning the idle screw. This will minimize wear on the tip of the idle shaft where it contacts the slide.

 

[Rhodester]

My setup at 2800' and a dry climate is 152 main, 42 pilot AS @ 1 1/4, DEK/3, #7 slide. When it's good and warm out (or higher elevation) I go to a 150 main. With this jetting I'm on the safe side (rich rather than lean). I went though 13 needles, 3 slides, 9 main jets, 5 pilots, and lots of time logging the results to settle on this combination. I'm currently running a RAD valve, FMF -35 (woods), 'Q' silencer, milled cylinder base and head, timing advanced 1/2 a space in front of the most advanced timing mark. I'm using MX2T @ 40:1 and 91 octane gas. I have a UNI filter and the air box lid is on (minus snorkel). If you need more detail on different needle characteristics just let me know.

 

[fundgh]

I just bought a used KDX220 with FMF woods, RB Carb work, Boysen reed... and the jetting is CEK needle clip #3, 40 pilot, 150 main. The guy I bought it from said he mixes 32:1. The lid is off the box and has a UNI air filter. I have not taken it out yet, but how is this for a starting point?

 

[04kdxchris]

I have nothing to add about jetting but where did you get those neoprene fork skins? I also hate those covers that they put on. How much were they?
Chris

 

[strider80]

I will put my $.02 in here, 2000 KDX 200 Gnarly Rev pipe, turbine II, Boysen power reeds, drilled airbox lid, FRP torque ring. Sea level in Seattle, I run the FMF recommended(at least this is what they recommended a few years ago) jetting, 152main, 45 pilot, R1173L needle 3rd position and about 1.5 turns on the air screw. It is a touch rich on the plug, very little drool on the pipe, never fouls plugs, starts really easy, pulls real nice from idle to the top.