Bike year & model = 2010 ec300
Temperature (degF) = 50
Elevation (feet) = 5280
Main jet = 165
Pilot jet = 40
Needle & notch = N3CG notch 3
Air screw setting = 2 out
Throttle valve/slide = #7

Results: Good all around, touch lean off idle.

Bike year & model = 2011 ec300e with s3 head black insert
36 mm pwm carb ( as delivered stock)
Temperature (degF) =50 to 95
Elevation (feet) = 500 to 3000
Main jet = 165
Pilot jet = 45
Needle & notch = NEDW 2nd from top
Air screw setting = 2.5 turns out
Slide = stock
Float = 8mm

Great linear manageable single trail jetting, just keeps revving, will idle around with instant smooth roll on. Bottom end smooth.

Leaning pilot to 42 sacrifices good idle for less burble, but the burble really is just a sound and doesn't affect handling/ roll on from closed throttle.

Bike year & model = 2011 ec300e with s3 head black insert
36 mm pwm carb ( as delivered stock)
Temperature (degF) =60 to 95
Elevation (feet) = 500 to 1500
Main jet = 172
Pilot jet = 40
Needle & notch = JD Blue 3rd from top
Air screw setting = 2..25 turns out
Slide = stock with perfect idle
Float= 8mm

Punchy racey, go up a gear or two and have awesome traction, hand over hand hill climb power with low revs and wide throttle openings, will not stall. Wheel stands in third from walking pace. Still revs out but not as moonshot as the suzuki needles. Has that "450 ish" roll on ( but I'm not kidding myself, it's not a fourfiddy)

This is my stock jetting. It's 1 step richer on the pilot and main than jd recommends, pilot for the grunt, main for the tighter squish head. Great plug colour with BR8ES and 80 to 85 km to reserve. Spooges to the end of the cap in half a tank.

Edit: For winter I've gone to clip 4, was getting a bit vibey and bit of a more obvious transition onto the pipe, with the clip movement fixed, I also use this all the time now, it's just so good.

Edit: this setting for me must be pretty well spot on, the air screw works.

Edit..again: after installing MPro T3 cable and getting some more freeplay in the cable, i went to P38 JD Blue 3 172 (jds recommended jetting except for one step higher on the main) , its just awesome a super linear torquey push from nothing to top end, with the usual surge onto the pipe...love it, as easy to ride as the nedw, but with punch! but its noticeably vibey -er, so I wrote to JD about it and got this back from JDean himself:

Mike,

Yes, you are on the right track using a slightly richer jetting (sic; for the higher comp head). The vibration is indicatiing you're making more power now. The jetting sounds close to perfect, and I'd suggest comparing the Red needle in clip position #4 from top to running Blue #3 clip position. The #38 pilot jet is a good setting. The main jet can be lowered a step or 2 with the 36mm carb, to near #168 or #170,-if you find the bike runs rich when you open it up after riding in slower conditions and find that the motor doesn't clean out quickly

1 also set float to about 7-7.5, AS 1.75 turns

2006 EC 300
air temp around 10 degree celsius
elevation around sea level
#42 slow jet
#178 main jet
CCK needle 2nd clip
Airscrew 1 2/5 out
other: additional reed cage spacer (makes all the difference)

Runs clean from nothing to long periods of WOT. The additional spacer takes the snap out of the low end throttle response, almost like a trials bike, very controllable. Also good fuel economy at trail riding pace.

2003 ec 250
Air temp 10 to 20 degrees celsius
elevation sea level
dominator mixed at 32 to 1 with premium pump gas
42 pilot
185 main
JD red 3rd clip from top
stock #7 slide
Air screw 2 turns out

It runs clean at low throlttle it doesnt load up or sputter and is smooth but strong in the mid to top, I get a tiny bit of spooge if I putt around alot and none if im on the gas like I should be.
I can get 100 km out of my oversized clark tank with some gas to spare.
When it gets hot (30 or so) mid summer its a little rich and doesnt like to idle but runs fine other than that, turning up the idle speed will fix it, I dont rejet for it because its not that hot much at all.
I switch to the JD blue 3rd clip for winter riding or the N1EF 3rd clip if its really cold with the same pilot and main.

Bike year & model = 2011 XC250 6-days, 36mm carb AS2
Temperature (degF) = 45-75, usually high humidity
Elevation (feet) = 880ft. most of the time
Main jet = 175
Pilot jet = 42
Needle & notch = N1EF, 3rd
Air screw setting = 1 3/4
Throttle valve/slide = 6.5

Results:
Awesome! This bike has great bottom end, mid-range, and top end. Plug looks perfect. I wish I could get the 300 running this good.

Bike year & model = 2011 EC300, 38mm AS2 carb.
Temperature (degF) = 60-75
Humidity: Like Bill Cosby's throat after his tonsillectomy- dry...dry...dry...
Elevation (feet) = 4000-6000.
Main jet = 172
Pilot jet = 38
Needle & notch = N3CH, 2nd
Air screw setting = 2 out
Throttle valve/slide = Stock (7.5, I think)
*RB Squish-Band mod.
*Float level set at 8-8.5mm
Milage: Outstanding! 70 mi to the stock 2.5 gal tank in a good mix of single track, fire road, a few rocky hill climbs. Only thing missing is sand, mud (what's that?), and WOT stretches.

Results:
Clean throughout. Idles well and consistently. Feels like I could go a tad leaner, but I prefer a little more grunt to a really crisp rev rate.
Thanks to all the activity in the jetting forum, I got it dialed on the first attempt. Pulled the carb 2 more times to to get the float height dialed in and the final pilot jet installed.

Bike year & model = 2012 EC300R, 38mm carb AS2
Temperature (degF) = 45-75, usually high humidity
Elevation (feet) = 880ft. most of the time
Main jet = 178
Pilot jet = 45
Needle & notch = CCK, 3rd
Air screw setting = 2
Throttle valve/slide = 7

The bike was delivered with a 42 pilot, 175 main, and a N1EF needle. It ran like a 300cc 125. A complete stinker. No bottom end, a big void in the middle, and then full-on screamer on top. WTF! We went all over the map using the stock needle in every clip position, then going with a fatter pilot, then fatter main, all one change at a time. We made improvements but no matter what, there was a bog in the mid-range and it was still weak on the bottom.

After many frustrating changes, I pulled the 36mm carb from our other bike and without making any changes, installed it on the new bike (see settings in my other post above). It was like night and day! Now it ran like a GasGas 300 should. But I was faced with a dilemma. Now I had a 38mm carb I didn't want to use and a 2011 bike with a gaping hole at it's core.

I ended up ordering a CCK needle out of shear desperation. When the needle arrived yesterday, I installed it in the 38, reinstalled that carb on the '12, and sent my rider out for a test. He came back smiling from ear to ear!

I rode the bike today and I'm still a little disappointed in the mid-range. I'd like to try some more needles...

Well there is no shortage of info here on that! I just bought a new selection of both single taper C/D series and OEM Suzuki needles to tune the 250 if the JD Blue/Red doesn't do it. I hate wasting time jetting and waiting for stuff to show up just to try. You can usually get a bike very close with the right single taper needle, and then perhaps find something thats just a bit better for you in the OEM tapers.

2012 GAS GAS 300 Jetting
 

I'm in Texas and have my jetting pretty close.

42 pilot
N3CH #3
175 Main

This is the jetting I ran on my 2011 300 Race, but I think it work better on this bike.

Haydn #28