Rich 2007 EC300 Wants #8 Slide

[ssaulnier]

I have been methodically leaning out the jetting on a new to me 2007 EC300.

The bike started out with a CCK needle, #7 slide, 172 main jet and 45 pilot jet. Plug was black and wet. Bike did not need choke to start. Would not idle and would blubber badly until cleaned out on the main jet where it would go from blubbering to picking up the front wheel and screaming.

I cleaned the nasty Ethanol fuel green film out of the carb, mixed fresh 93 octane gas 50:1 Klotz Super-Techniplate, set the float level to start with but that did not help. So I cleaned/polished the float valve seat and installed a new spring loaded needle valve but the bike was still very rich.

I tried all of the normal needles and main jets and pilot jets and set the fuel level in the float bowl a little lower so the bike doesn't drain fuel on the side stand. She finally ended up with a NECF needle with clip in the top position, #8 slide with a notch I cut, 38 pilot jet and 168 main jet. It was about 50 degrees when I tested it last night and it ran relatively clean throughout the rev range.

Compression is good at 165 psi, the reeds are original but are not chipped yet. I wonder if they are a bit weak? There is just enough hours on the bike to wear out the original chain. Sprockets still look good and you can see cross hatching inside the cylinder and not too much piston ring blow by when you remove the expansion chamber and peek in the exhaust port.

This bike seems to like a lot leaner jetting than anything else I have seen listed.

Should I be looking at anything else?

Thanks, Steve

 

[(F5)]

Are you confident you have got enough goop out from the emulsion tube and air holes to the tube?
Mine always needs choke to start when cold. Old gas makes it blubber until its proper warm, new gas behaves better.
Reeds will be fine if not damaged. Check filter not clogged up by some crazy oil, but petrol should clean anything use air filter oil.

You haven't somehow got hold of the black cat pipe? I tried one and it was miserable until cut out. Nickel plate one should be just fine.

 

[ssaulnier]

F5, Now that I have reduced the size of the jets, installed #8 slide and suzuki needle it does start nicely with the choke on.

I cleaned the carb twice and removed the emulsion tube too. I also tested for leaks at the jet block like on the You-Tube video Keihin PWK 38 S1) Idle Fix.

I replaced the air filter with a new one, but noticed no difference.

I need to double check the needle that I have in the bike now. I may have mistyped the needle code. I thought I was buying a leaner needle than the one I just pulled off my receipt. Maybe I need to buy a leaner needle. I'll check that tonight.

I'll also list the actual needles I tried. Don't have my notes here at work with me today.

There was a NOVA science show on TV Wednesday night about the Aurora Borealis (Northern Lights) and Aurora Australis (Southern Lights). They visited Southern New Zealand and it really made me want to visit. One day...

Cheers, Steve

 

[ssaulnier]

And yes, I have the nickel plated pipe on the bike.

 

[webmaster]

You don't say where you have either your idle screw or your air screw...

How many turns "out" is each of these?

jeff

 

[ssaulnier]

I have the air screw set to 1.5 turns out. If I turn the air screw in more than about 1/2 from closed the engine will die, but I don?t notice much difference in throttle response or idle quality between 1.5 to 3 turns out so I just left it at 1.5 out from seated.

The idle screw is turned in pretty far, but is not bottoming out it?s spring. The engine will idle for 5 to 10 seconds or so before it dies. While riding and hill climbing the engine is responsive and powerful. It will pull up hills down below the idle speed if I hold the throttle slightly open.

I get a little spooge running down the silencer after burning a gallon of fuel and the spark plug is black and there is a little burble in the mid range. So the bike is still rich, but doesn?t load up and comes on the pipe quickly in a very linear fashion.

Since I am using the top clip position on this NECF needle and the bike is still a bit rich I think I should try a NECJ needle to replace the NECF. I think I got mixed up on the needle codes and bought a richer needle than I wanted last time.

 

[Jim Cook]

I have the air screw set to 1.5 turns out. If I turn the air screw in more than about 1/2 from closed the engine will die, but I don?t notice much difference in throttle response or idle quality between 1.5 to 3 turns out so I just left it at 1.5 out from seated.

The idle screw is turned in pretty far, but is not bottoming out it?s spring. The engine will idle for 5 to 10 seconds or so before it dies. While riding and hill climbing the engine is responsive and powerful. It will pull up hills down below the idle speed if I hold the throttle slightly open.

I get a little spooge running down the silencer after burning a gallon of fuel and the spark plug is black and there is a little burble in the mid range. So the bike is still rich, but doesn?t load up and comes on the pipe quickly in a very linear fashion.

Since I am using the top clip position on this NECF needle and the bike is still a bit rich I think I should try a NECJ needle to replace the NECF. I think I got mixed up on the needle codes and bought a richer needle than I wanted last time.

Try a 42 pilot. It cleaned up my exhaust spooge problem, and still idled well. The 172 is very lean for open throttle operation. For any wfo use over three seconds, you may be better served by a 175.

 

[webmaster]

You need to turn down your idle and go with the 42 pilot jim suggests. Your idle screw is too far in - too much fuel/air coming from this and not through pilot circuit - which is why your air screw doesn't seem to have any effect.

I have heard of this condition referred to as "pulling over"... Pulling too much fuel from needle/nozzle and air from slide pulled up bypasses pilot. You lose the separation between these two fuel "circuits"...

When I see someone with a 38 pilot and looking for something leaner - this is usually the situation - and is aggravated by the n1ef needle that is used oem....

Also, note that this carb is happy with 2- 2 1/2 turns out versus 1 1/2 turns out - this will also send some "off into the weeds"...

jeff

 

[ssaulnier]

Thanks for that advice Jim and Jeff. I will try it again, but I am not sure it is that simple.

At some point, I tried to back the idle screw out with both a 45 and 42 Pilot jet, but that did not seem to give me a good idle.

Last week I installed a leaner NECJ needle.At 50 degrees F the bike starts on the choke and idles a little better, but I didn't get the chance to warm it up and ride it though.

Two weeks ago I burned up about 1.5 gallons of gas on flowing single track. The bike was still rich. It was never lean and never pinged or rattled. It was set up like this: NECF needle with clip in the top position, #8 slide with a notch I cut, 38 pilot jet and 168 main jet. It was about 50 degrees.

It seems like that should have been lean, but it did not feel or sound lean.

 

[ssaulnier]

Jeff,

Are you saying that the AS1 carb when mated to the 2007 EC300 actually works better with the Air Screw at 2 1/2 turns out?

So that implies that I should select a pilot jet that works best at 2 1/2 turns out from closed?

Or are you saying that 2 1/2 is just as OK as 1 1/2 turns out on the air screw?

What is the maximum number of turns out before you worry about the air screw vibrating out?

Thanks, Steve

 

[webmaster]

Yes. In my experience, at 2 to 2 1/2 turns out and a larger pilot - it works better. Then you can turn down idle (back it out) to improve separation of carb circuits.... The air screw will then have more effect - e.g. you will be able to fine tune - like a quarter turn will make a difference, etc.

If you are worried about losing idle screw - you could put a very small dab of low strength loctite on it's threads. Let it dry completely prior to installing.

jeff

 

[ssaulnier]

Thanks for the tips about being 2 1/2 turns out on the air screw. I will try that this weekend.

 

[webmaster]

In my mind - #8 slide is good along with everything else.... Be sure to re-set idle screw to lower level.

jeff

 

[(F5)]

Don't be afraid to try needles. You just can't jet the wrong needle to work.

 

[(F5)]

When it's right you'll know. Wheelies at will mean you're close. Wheelies when you don't quite expect are the biz.

 

[ssaulnier]

Thanks for the guidance guys. I will adjust the idle screw more closed and try 40 and 42 Pilot Jets this weekend with the Suzuki NECJ needle.

Steve

 

[ssaulnier]

I made changes as you suggested and noticed great improvements. Increased MJ, PJ, opened AS to 2.5, lowered slide so just barely open, raised NECJ clip to eliminate midrange blubbering. Ended up at top clip. Think I should get a leaner needle since I am at the top clip and I usually ride at much warmer temperatures 90 to 100 deg F.

More low end from below idle. When I crack open the throttle from idle the front wheel will come up. Power builds linearly into a Good clean midrange that revs out nicely.


2007 Ec300 Temps 60 deg F
38mm AS1
PJ 42 (was 38)
MJ 172 (was 168)
Slide 8
AS 2.5 out (was 1.5)
NECJ top clip (was clip 3)
Idle screw adjuster to open slide just a hair