EC 300 2012 - jetting for singletrack (not racing)

P

pHreaC

New member
Hello,

I am a new GG owner from Belgium and am looking into getting my bike right for me. I'm not racing, love to play around in the woods, got some open gravel roads connecting singletracks. Don't need the most power out of my bike, but am looking for a nice crisp performing machine with decent miles per gallon.

I have browsed the forum a bit to look for a good jetting for my bike, but up till now I haven't come up with a good setting just yet.

I think the bike is a bit rich for the riding I do, I also get a lot of spooge drooling down the exhaust. It's not the mufflerpacking, since the bike has only run 100km (+-60miles) or so.

Bike is completely stock now:
main 175
PJ 42
needle N1EF clip 3
AS 1 out

I run premix at 1:50, riding around sealevel with temperatures in the range of 5-25?C.

PLEASE HELP

pHreaC
 
So you have browsed, but have you tried anything yet? Have you tried lifting the clip one position on the needle to lean that out. It appears you're once clip richer than what most the bikes deliver with. You do have some coolish temps though.

Thumperrider1 has installed the NEDJ needle in his 2012 and is very happy with it. It gives good clean power off the bottom with no real big hard hits waiting to bring you undone. Want more power, open the throttle more. It may be what you're looking for for your forest fun!
 
Lowering the needle is an option, but is it enough?
I was more thinking that I would need for example a 38PJ and a 170 main.
Some more miles per gallon would be appreciated, but I don't want to lean the bike out to much and create excessive wear and tear.

ps: 5-25?C is 40-80?F
 
i would try one thing at a time. drop your main jet to a 172,keep everything else the same.as much as some people say the main jet doesn't come into play, i have found that a skinnier hole in the main makes the bike leaner across the entire rpm range.
 
That is what I have found as well, adjust de PJ for the lower throttle opening and the main for full open position. This is why I wanted to have em both go down.
I would think that if I were to change one jet at a time, it would be the PJ.

grtz

pHreaC
 
maybe this helps to understand

Full load:
larger main jet nozzle -> mixture becomes richer
smaller main jet nozzle -> mixture is leaner

1/4 to 3/4 throttle:
Needle-> Set-> clip higher lean
Needle-> clip lower down the page-> richer

1/8 to 1/4 gas:
Slide> cutaway more> lean
Slide-> smaller cutaway> richer
larger pilot jet -> richer mixture
smaller pilot jet -> leaner

Idle to 1/8 Gas:
Idle screw pure-> more idle
Idle screw out-> less idle
Mixture screw (air filter side) -> in richer
Mixture screw (air filter side) -> out leaner
Mixture screw (cylinder side) -> in leaner
Mixture screw (cylinder side) -> out richer
 
Yes, I already knew what the different jets and needle are for.
The theory is quite clear to me, it's the practical side I am looking for.

I suppose that some have tried different jettings to increase mpg and still remain with a lively engine that responds well and is not overly lean so that it may become hazardous. It's this info I am looking for, what jetting is working for them and might work for me too.
Power is abundant, so the only thing I am looking for is a nice crisp engine respons that is not too lean that the engine might be damaged and this would also imply good miles per gallon.

Still, thanks for the respons!
 
Jakobi has this stuff figured out!

On the 2012 use the NEDJ, 40 pilot, 172 main. Super clean off the bottom and runs crisp up to the top. Does not have that massive hit that gets you in trouble. Try it.
 
Its true! I have a 2010 EC300R which uses the same 38mm ASII Carb, and have tried just about every combo of needle diameter, pilot, main, and clip position for the N1Ex, N3Ex, N3Cx, NEDx and NECx. The findings are well documented in the jetting section.

Thumperrider1 has implemented the NEDJ in his 2012 with good results, and I'm currently working with 2 others with 2012's in Australia to see what works for them. In my findings the stock needle has a really rich first taper, and a short straight section, which is what gives it the richness off the bottom (even if paired with a super lean pilot). The other needles work around this quite well. NEDx/NECx offer clean linear response, N3Ex/N3Cx have more of a mx transition in the mid range.
 
thumperrider1 said:
Jakobi has this stuff figured out!

On the 2012 use the NEDJ, 40 pilot, 172 main. Super clean off the bottom and runs crisp up to the top. Does not have that massive hit that gets you in trouble. Try it.
Click to expand...

Just wondering what clip position you ended up in? Temp and elevation also. Thx
 
Just installed the N3CW needle on 2nd clip.
This is giving a lot less spooge, the 'hit' is also gone, probably due to the thicker bottom of the needle. It really is a very different needle compared to the N1EF.

Starting isn't as easy as it was, need to crack the throttle in order to start the bike where before I only had to pull the choke lever. Not sure if the air screw is ok, don't really notice a difference between 1 turn or 2 turns out.

grtz

pHreaC
 
Just for your info,

The N3CW at pos 2 is significantly (up to 20%) leaner than the N1EF#3. Thats a pretty big jump to take, and you might have been happier starting in clip 3 or 4 and then leaning off to find your ideal setting. The N3xx also has a fat tip as you know, and requires a size or 2 larger on the main than you'd use with the N1EF.

For the idle and air screw, you need to back the idle adjustment screw down before the air screw will come into action. I found with the stock N1EF and a 42 that the slide was lifted quite a bit using the idle screw (turned in until the spring was fully compressed).
 
Thanks. Just for comparisons with some bikes here. Wence dropped the NECW into his 2012 at clip 2 with a 42 and 175. Definately still a bit rich off idle, but on the needle sounds crisp as. Believe he's closer to 90/95F though.

I personally find that the N3Ex and NEDx cross over pretty evenly clip for clip.
 
Went for a ride today with the N3CW at clip 2, air screw 1.5 turns open. Engine is not smoking at all, when reading the spark plug it is a light tan brown...
Maybe a bit on the lean side, however I have ordered a N3CJ needle and I will probaly be installing this in the 3rd clip. Not sure if I will have to go smaller on the main jet, it is 175 now but am thinking about switching it to 170-172. I don't ride a whole lot of long stretches.

First will try the new needle on 3 and we will go from there.

Bike is a bit harder to start now, any suggestions to fix this?

thx

pHreaC
 
Cold starting or hot starting harder?

You never mentioned what elevation you're running at either.

To get the bike to start well and idle well you'll want to follow the normal 2T jetting 101 to set up the pilot circuit. Start leaning out the Air screw for the best idle and response. If things haven't improved by 2.5 turns out go to the next leanest pilot and try again.

My findings are that the newer bikes like either 38/H 40/W 42/J. Richer should still run fine with some burbling before coming onto the needle. Lifting the slide (opening the throttle) leans things out which will get it to start again. While on this tangent you'll find very little difference between the N3CJ and N3CW. About the same difference that a change in pilot jet would make.
 
Milage

To the OP:
You mentioned a desire for better mileage. Cleaning up the jetting is a start, but I had to raise my float height about 1.5-2mm in order to get an appreciable gain in mileage.

Also, I have always had to whack the throttle to get my two-strokes started.
 
I ride at sealevel.
And it's the cold starting that has gotten a bit worse than before, I need to open the throttle in order to get her going.

Since the airscrew doesn't do much, perhaps I should go leaner on the PJ as well...

38PJ
170main
and N3CJ needle on 3

sounds about right?
 
Nup... You're going about it all wrong and stabbing in the dark.

42 N3CJ#3 178

Set the float level as well. They are renound for being too high from the factory. See Ando's thread for pics.

Tune the idle circuit until the bike will idle on its own, and starts easily. As Ando said, its not ununsual at all for a 2T to like a bit of throttle when starting (when up to temp). Cold start I just use the choke and it fires. The 42 pilot and the J diameter will get you very close. Set the air screw at 1.5 turns from fully closed. Set the idle screw at a setting it will idle, and then back it down to a point where it will sustain an idle on its own. Fine tune the AS until you get best idle. DONE! (Make sure the bike is up to running temp before you set this)

Then.. Work on clip position! Ride the bike between 1/4 throttle and 3/4 throttle. Mark the throttle out with a texta/nico so you know where you're holding it. If the bike starts to burble up and doesn't want to rev clean then you're rich. Move the clip up 1 position. Ride again. You'll find the clip position that feels the most responsive and best power. If you go to far you'll start to get flat mushy power (like when the bike isn't warmed up), hesitation when opening the throttle, pinging, excess heat, and a white spark plug. The signs are there for you to read. DONE!!! I recommend going richer on purpose just to highlight the effect you're trying to avoid.

And finally, run a 5 second under load WIDE OPEN THROTTLE. I usually do it just out the front of home cause I have a slight incline. Punch it into 4th/5th gear at walking pace WOT and let the engine work. Pull the clutch and hit the kill switch at the same time. Pull the spark plug out (make sure not to try and start it or turn it over at all) and read the plug. Few different methods to doing this and thats a topic in itself. Then adjust as required up/down a size at a time and repeat process. PS. Both steps above can technically be done without a main jet at all, although it will make some difference right across the board its not enough to change too much.
 
So according your findings I should not go leaner on main and PJ. (richer even!?)

Now I'm totally confused...

I have a 42 PJ now, on which the bike feels ok, but I can't notice the air screw doing anything with it being up to 3 turns out, thus I thought it was rich, and leaning it out would be better
a 175 which isn't all that important to me since I don't ride full throttle
and the needle I was going to set on 3rd, so we agree on this one

I've searched the KTM EXC300 on this as well, and they suggest
main 162-165 (which is a whole lot leaner than mine)
PJ 35-38 (leaner as well)
needle N84K #2clip (probably leaner than N3CJ on #3)
but this is a 36mm carb, which means higher velocity, thus more venturi, thus more sucking out fuel, thus on my 38 slightly richer to compare

wouldn't this imply that I should go leaner instead of richer???
 
You must log in or register to reply here.

Similar threads

D
2000 EC250 jetting with FMF gnarly
Replies
1
Views
73
(F5)
(F5)
N
Jetting EC 125
Replies
2
Views
193
Noobi06
N
B
Jetting for 2007 EC300 - something isn't right
Replies
2
Views
3K
(F5)
(F5)
M
Engine surge/runaway?
Replies
4
Views
163
Mustyeddie
M
G
2001 EC250 Jetting
Replies
12
Views
4K
(F5)
(F5)
Back
Top