Running rich EC300

[swegass]

Hi,
Just bought a 07 EC300 and as I have little experience of this kind of engines (only old ones without reed and pipe) I have to get some help where to start out in this matter.

My feeling is that it's running rich, idle is a bit hard to set as it has a tendency to stay on high rpm and needs quite some time to settle down if it ever settles.

It sounds rich and rough when there is no load on the engine at lower rpm's, but loading it slightly makes it run "clean" (this is off the pipe).

After running on low to mid rpm's (off the pipe) it will stumble when accelerating just before getting into the powerband if I flip the throttle a couple of times it cleans out and hits the pipe in a good way with full power as I belive

I need some hints where to start to look for this problem (well now if it is a problem or if I just ride it too soft lol) like carb, PV or reed, I have to add that it's running on a 40 gear (it was set up for street use when I bought it and will change to 48) in the rear but not sure at front maybe 14??

Please any suggestions will be welcome.

Lars

 

[Zman]

You may want to try opening the idle mixture screw to lean it out slightly (1/4 to 1/2 turn and see if that helps.

 

[swegass]

Thank you Zman for your fast response I will try that today and post the response.

Meanwhile I'm open to more tips if this won't do it!

Lars

 

[(F5)]

You need the right needle before anything will be worth adjusting. Heaps of threads here to search and read for your year.

 

[swegass]

Yes I know the needle is very important but have no clue of what is a good one?
Can anyone just give a number for e good choise, Before I tear down the carb.

 

[swegass]

I turned the idle screw out 1/2 turn, a lot better now but migth need to lean it a bit more. It's now 2 turns out will try a 1/4 more tomorrow. Lets assume 2 1/4 to 2 1/2 is optimal is this a sign of reducing the idle jet and if so by how many steps.
Amazing how such a small adjustment can change things around
I felt a new smell from the engine now, a bit leaner higher exhaust temp so I Think the smell came frome a hotter pipe
Before I hade to force it to hook the pipe but now it kind of drags itself into it, as Im not used to such Power (Before Montesa 260 trial 1989 15,5 HP) well it's scary in an awesome way

 

[barbotte]

i am not expert but look at your needle first ,, you might be able to move it up 1 notch before changing it ,,, also dont forget its better to be richer than leaner (easier on engine)
cheer

 

[(F5)]

Look i don't mean to be rude but this has been covered again and again. My 07 uses a N3 something needle (didn't write it down) but there's even a sticky of jetting database.
Try a suggested needle and experiment from there. With the std N1EF (or G) it will never run properly at low throttle no matter
what else you change. I promise. There's heaps of good info here but you'll have to dig a little.

 

[swegass]

Well I have to apologies for starting up a new "OLD" thread but I'm new here and searched in FAQ, but now I use the correct Search "link" and found a lot
Anyhow I'm very pleased to still get some good advices in this forum
There is not much on GASGAS here in Sweden so I really enjoy being around here, tons of relevant info.
My English isn't the best but you guys still seem to understand my Q's
At the moment I'm quite happy with the engine performance, only thing is it needs a really powerful hit on the kick to start.
Will take of the carb and check jetting, needle and its position and work from there if needed, yes also float level!
Thanks a lot for helping me out
Hope to stay with gasgas even though I should be a Husqvarna rider

 

[Flashlight]

This is what I've been running for the last two years in my 06 EC 300.

Needle: N3CG in the middle position.
Pilot: 42
Main: 178
Airscrew: 2.5 turns out.

That needle is from Yamaha. You can order them from a Yamaha dealer or online. They were optional in YZ-250's.

Yamaha part number for the needle: 4SR-14916-CG-00

I would buy a 40 and 42 pilot, the needle, and a 175, 178, and 180 main and experiment. In the hot summer a 40 and a 175 work but most the time I don't bother changing.

My elevation is 1000- 4000 ft.

Jetting questions are usually answered at "Enduro Intake/Carburetion - 2 stroke" section of the forum. Try there for more info.

 

[thumperflipper]

on my 07 I jacked with all sorts of different needle/pilot/screw/main combos for a couple years, same problems you are having. I finally broke down and bought the JD needle kit and it still sucked. I called JD and he sent me a fatter needle, the rationale was my bike likely had very high time on it (I am the third owner) and the "needle jet" as he described it gets worn out from the needle going in and out of it. So he suggested a new carb OR to try a fatter needle (which he sent to me at no cost). In my case, he was right, and the fatter needle fixed it. Now it runs clean at all throttle positions

 

[swegass]

Interesting reading thumperflipper, yes I understand this wear of the needle jet cuz I have replaced many of them and also the needles in old car carbs back when I was a auto mechanic.
You say it was fixed with a "fatter" needle, I read that as if the needle have a fatter diameter and not as in a needle that gives fatter mixture??

Please let me know if im right.

Is there no way to change the needle jet (no spare part ?)

Lars

 

[swegass]

Hi Flashlight,
I had a N1EF in mine and now changed it to N1EG as it came with the bike and is supposed to be a bit leaner.
Not a big differance might be a bit more power when I'm on the pipe.
How does my N1EG differ from your N3CG?

 

[Flashlight]

The last letter "G" means a slightly leaner diameter so it will run slightly leaner around 1/8 - 1/4 throttle than an N1EF. Really not much of a difference between those needles.

The big improvement is in the taper profile. The N1EG or N1EF are too rich.

The N3CG has a leaner taper profile so it leans out 1/4 to 5/8 or so throttle which is what your bike likely needs.

The "C" is just a slightly richer clip position. The equivalent of being a half clip richer. The N3CG is identical to a N3EG with the clip half between the second and third position.

 

[Jakobi]

The diameter has next to no effect on the N1E series needles, because the straight section is so short that many bypass it entirely with a few turns of the idle screw (lifts the needle up onto the 1st taper).

 

[Flashlight]

Interesting, I knew they were bad, not that bad though.

I should add swegass, there is nothing special about a N3CG. It works for me and my bike. Enough that I stopped experimenting anyways.

Go over to the Intake jetting section of the forum and you will find many different kinds of jetting setups working. The N3CG (or N3EG) is just one that seems to work for many with older bikes.