More jetting problems!

[juzzasmith]

Hi guys, I've got a problem with my '05 EC300.
I've had the bike a couple of months and it's been running great apart from a sputter at 1/8 to 1/4 throttle.
The jetting in the bike is as follows;

slide #7
needle N1EG 3rd clip
main 175
pilot 40

I've tried a 35 pilot, needed 2 1/4 turns out on the air screw to idle properly and its still sputtering, and after a plug chop the plug is black.

I'm riding at around 800ft at 20c to 25c and the bike is running ok at all other throttle openings, just a little rich.

Any thoughts would be much appreciated!

[widebear]

For me a #9 slide, used in conjunction with an o.e needle cured a similar problem, though a lot of guys who have had good success with the LTR kit claim it cleans up that particular issue as well. I also know of one guy using the JD jetting needle with a #7 slide and is very happy with the results

[JoshP]

Your pilot is most likely not your issue there since it's happening in your 1/8 to 1/4 throttle spot. Have you experimented with moving your clip up on the needle? If not I would put it on the the 2nd to top and top to see if there is a difference. It's worth a shot prior to buy new parts. Good luck with it!

[juzzasmith]

Thanks for the advice guys, just tried the clip 2nd from top and there is no noticable difference, may try the top clip before trying anything else or buying any new parts, but I'm just a little worried about going too lean.

Have been considering the LTR kit but have read some mixed opinons about it on this forum, back to a bit of head scratching I guess!

[Eric K]

The N1EG is a triple taper needle that tends to be rich in the 1/8-1/4 throttle range. For track riding, they can be tuned reasonably well. For technical/ trail riding they are finicky and tend to be sensitive to ambient changes.

Using a leaner slide like widebear can help compensate for the 1/8-1/4 throttle richness of the triple taper needle.

Using a straight taper needle (like LTR) is another way to compensate for the 1/8-1/4 throttle richness.

[juzzasmith]

You guys are spot on, I moved the needle to the top clip and it almost got rid of the sputtering, found I was way too lean on the pilot so went back to the 40 and also tried a leaner 172 main.

From 1/4 throttle to wide open is almost perfect now, just a touch rich if anything, its just that rich sputter at just open to 1/4 throttle that I can't shift with the N1EG needle.

Going to try the LTR needle, thanks for pointing me in the right direction, I was going round in circles thinking it was the pilot!

[cdn280]

Its interesting how a variation of jets and needles can both work but work for different reasons. (pullover from other circuits apparently)
Here is my experience with an LTR kit...
My jetting which worked pretty good for the last 2200kms or so, was made up from all the extra carb parts that came with the bike, but I ended up buying an even leaner 175 main in its last setup.
What I was running pre LTR:
N1EF needle
#7 slide with clip in middle
42 pilot
175 main (started with 180, then went 178, then 175)
air screw about 2.5 turns
Plug color was much better with a 175 after a hispeed check but pretty dark after slow riding, idle was pretty good. Most of my riding is tight single track, 2nd to 4th gear stuff, wide open stuff is pretty brief.

After first installing the LTR kit:
180 main
LTR needle with clip in middle
45 pilot
air screw about 2 turns
Idle screw backed out a couple more turns

It didn't initally go too well, maybe it was me, maybe it was a stuck float/debris, maybe the idle screw turned out too far or not far enough as it said in the instructions, don't know, but it didn't fire in the first couple kicks with the choke on as it always did, so turned off the choke and kicked lots. It was flooded bad. So bad that after re&re'ing the carb again, with a new plug, it still wouldn't fire and ended up using the crankcase drain bolt and got about 1/2 oz of gas out of it. Plug very wet.
So it came apart again, blew it all out again, but this time I put a the leaner 178 main, moved the clip up 1 notch leaner, and put in the leaner 42 pilot I had. Fired up 2nd kick.
The test ride went pretty well, a little too crisp it seemed, on a top speed run it revved to the moon a bit too easy, and seemed like a little detonation was happening if you chopped the throttle from hi revs. A plug check proved it was too lean, on top anyway. So, the 180 went back in, and the clip moved back to the centre. The 42 pilot was left in for now. The bike starts from cold with a very wimpy 1st kick now. The kickstarter doesn't turn over the engine much, or very fast to begin with so I had always kicked like hell with the lever always whacking the footpeg. Now just a half assed kick works, hot or cold. The old cold start ritual was always choke on, 1 or 2 kicks, turn off the choke right away, then play with the choke lever for a few secs until it would take throttle cleanly, and try not to let it stall out. After a min or so, it would idle fine by itself. Now, its choke on, 1 kick, and it will idle without overrevving with the choke left on for a few secs, then flip the choke off. It idles even better than before but i've only had a couple brief rides so after some long singletrack I'll check if I need the 45 pilot, but its much smoother/controllable power from idle to top. Not to mention that the idle screw in no longer coil bound.
Highly recommended !!

[juzzasmith]

Got the LTR needle today, fitted and jetted to Les's baseline settings; 178 main and 45 pilot, needle on middle clip.
Certainly had a more hit off the bottom, but still got that sputter on small throttle openings.
Played with the clip position with no improvement, fitted a 175 main which got things a bit sharper but no real improvement with the sputtering.

I've finished up today with a 175 main, 42 pilot and needle on the top clip and it's still crap on small throttle openings.

Really frustrated, never want to see another carb as long as I live!

Anyway, the plug looks fine, still too dark after a plug chop at 1/8 throttle, do you guys think I should try going leaner on the main and pilot?

(Not today though cos I need a beer and some time away from the bloody bike!)

[jeffd]

Did you reset the idle screw when you installed the new jetting? You should back it out, or you will be "pulling over" from the get-go.

Where are you at with your air screw and idle screw? How many turns out on each one?

I would go with needle on second clip from the top and set your air screw at 2 1/2 turns out as a starting point. I wouldn't go leaner on the pilot.

If you are messed up because your idle setting is too high - then you may want to go back up to the 45 pilot.

You might want to make sure the carb is "clean" - blow out all orifices with compressed air.

jeff

[juzzasmith]

Originally Posted by jeffd

Did you reset the idle screw when you installed the new jetting? You should back it out, or you will be "pulling over" from the get-go.

Where are you at with your air screw and idle screw? How many turns out on each one?

I would go with needle on second clip from the top and set your air screw at 2 1/2 turns out as a starting point. I wouldn't go leaner on the pilot.

If you are messed up because your idle setting is too high - then you may want to go back up to the 45 pilot.

You might want to make sure the carb is "clean" - blow out all orifices with compressed air.

jeff

Idle screw is 2 turns out, air screw 1 1/2 turns out.
I've got a feeling you're right about the pilot, with the 45 the bike started easier than it ever has, just took a gentle kick. Usually it takes a few big kicks with some kickback.

I'm just feeling very frustrated cos nothing seems to work to clear the stuttering and I'm going round in circles again. My feeling is that the baseline jetting was pretty good straight off and it was certainly stronger off the bottom, it's just that damn sputter!

I have given the carb a clean out with carb cleaner but haven't tried compressed air cos I haven't access to a compressor.
Got a clean air filter and new exhaust packing in the bike, I have a couple of small dings in the expansion chamber but nothing that should affect it. The sputter is at all revs at just a crack of throttle.

A few guys have mentioned running a #9 slide (mines a #7) to clear up the sputtering, but I really want to try everything else first cos those slides ain't cheap!