Changed Jetting now having issues

[icebergstu]

Hey Legends,

2005 GG EC300
Just installed:
Needle : CCK middle clip
PJ : 42
MJ : 175
AS : 1.5 turns

20deg Celcius
500ft - 1500ft only

Idle adjustment is now full in but still only just managing to stay alive
Turning the air screw seems to do nothing until full in and it stalls

Rode it and its shocking on the pilot, cracking, missing, really nothing until it hits the main jet...

What do ya reckon? Pilot too rich/lean? I havnt got bigger than 42.
Was running 40 pj and 172 main with N1EG needle, using a lot of fuel and smoking/spooging a lot.

Nee top end 1 ride old

Stu

 

[icebergstu]

Kept the needle and went back to 40P and 172M and it's better but still very low all in idle.

Also noticed it's worse at idle when light is on...

The bike is great though the mid and top...

Could I have an electical issue?

Stu

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[Zman]

I think the idle mix and pilot jetting is still off. The light adds more load on the engine and makes it more likely to stall. Once you fix the jetting the problem should go away. If it ran better going from 42 to a 40 then maybe try the next size smaller pilot.
That being said it 40 seems lean to me. Maybe check your float height as it may be high. Does it leak fuel on the ground when you tip it off center?

 

[GasGas]

Confirm you can actually see a nice crisp round hole through the 42 pilot when you hold it up to a light source. Especially if it is a used piece.

 

[icebergstu]

I think the idle mix and pilot jetting is still off. The light adds more load on the engine and makes it more likely to stall. Once you fix the jetting the problem should go away. If it ran better going from 42 to a 40 then maybe try the next size smaller pilot.
That being said it 40 seems lean to me. Maybe check your float height as it may be high. Does it leak fuel on the ground when you tip it off center?

No I did the blow method and got it spot on.
About 45 degree tilt before any discharge from the bowl.

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[icebergstu]

Confirm you can actually see a nice crisp round hole through the 42 pilot when you hold it up to a light source. Especially if it is a used piece.

Yes, jet is clean through all 8 bottom and centre holes.

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[webmaster]

When you ran the n1ef it is "pulling over". This is a condition where the idle screw is turned all.the way in and the carb circuits are no longer properly separated.

Whenever one goes away from the n1ef to a more proper needle it is critical to back out the idle screw and reset the idle mixture screw Otherwise, you put in a good needle and pilot jet and you still have too much fuel from needle and air through slide at idle and it will still be pulling over...

And if you don't fix the your idle screw setting.when you swap jetting , then you start hunting for a leaner and leaner pilot jet until your jetting is, again, completely dorked.

If it were me, I would start with my idle screw backed out at least a turn, 42 pilot and set your idle screw at 2 and a quarter to 2 and a half turns to start. Forget the old standard of "1.5 turns out on air screw is good".

Ask jakobi where he has his idle screw set. How many turns out from coil bound.

Jeff

P.S. Others here have had good luck using an oem yamaha or Suzuki needle....

 

[(F5)]

You don't mention trying other clip positions. Try up and down to see what it's like. If better one way try another click.

 

[icebergstu]

Whatever I do it makes no difference at all...

So, I've stripped and leak tested the pilot circuit - all good
Set and re-checked float level at least 5 times
Changed from 38, 40, and 42 Pilot with no gains.
Changed from N1EG to CCK to CCL needle, no gains.
Changed from 170 to 172 to 175 mains, no change.

This bike was purchased as a project.
Seized top end, fresh bottom end. The bloke did the motor up and forgot to put oil in the fuel and she nipped up after a short time.
I renewed the top end, rebuilt the forks and had the rear shock rebuilt.

After the text book run in straight from the owners manual it was okay in the beginning with the BP5EY plug, N1EG needle, 40 PJ and 172 MJ but using too much fuel, smoking everyone out and spooging badly. It was not very smooth off the pilot and wouldnt idle even with the idle screw completely wound in.
Ring gap was perfect when I installed the C piston after a hone.

I had no idea what plug was supposed to be in there but the guy had given me a few new ones. I found out it was too hot.
Went from a lawnmower BP5EY plug to a BR8EG as suggested so I dont burn a hole in my piston apparently.

So after that first ride I did this:

• Installed new plug BR8EG
• Checked and reset float perfect both by blow method with seam, then checked again tilting carb connected to tank and then again tilting bike until it flowed out of the overflow. Spot on!!
• Checked for pilot leak by turning carb upside down, filling with fuel and blowing air into pilot circuit and looking for bubbles. Perfect seal, no issues.
• Checked all breather hoses, blew out and made sure all were clean.
• Changed to CCL needle and it was worse when running on the pilot but as soon as it got on the mains it was great.
• Changed to CCK needle it was no real difference and did a full 2nd ride. In the Vimeo linked vid you can hear how appalling it is running off the bottom.
• Now I've done every possible combination of bloody jets and needles besides going back to the N1EG and it's still shit.

Maybe...

1. When he did the bottom end work he screwed the timing up? Could that effect it?
2. Could my choke be causing the issue by not sealing properly?
3. Is everyone wrong about these jetting specs on the Jetting page?
4 is this just how these bikes are actually supposed to run?
5. Should I just get a bigger Power Band

How it is currently running:

https://youtu.be/SaGL9Xu6LS8

How it ran on the last ride:

https://vimeo.com/291824548

I can still try clip positions...havnt done that yet but will that effect the pilot circuit?

Stu

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[shawbagga]

Definitely #5 Stu. Bigger is always better!

 

[Jakobi]

Checked the reeds lately?

 

[icebergstu]

Checked the reeds lately?

Yep...immaculate

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[icebergstu]

I'm going to grab the mikuni I had on my WR300 and see if that will fit.

I jetted that once and it was perfect for 700hrs.

Stu

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[Jakobi]

It'll let you know if the carb is at fault or something else at minimum.

Very strange that the idle screw has no effect. Has the tip been snapped off it or something similar?

Air screw can have little effect until you get everything else where it needs to be.

 

[icebergstu]

It'll let you know if the carb is at fault or something else at minimum.

Very strange that the idle screw has no effect. Has the tip been snapped off it or something similar?

Air screw can have little effect until you get everything else where it needs to be.

When setting up the carb off bike the idle screw is pushing the slide up no probs.

I'm starting to think air leak, electrical, timing, so many potential possibilities....

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[Zman]

I would double check the crank seals. Especially the one on the clutch side as it will consume trans oil and make jetting impossible.

 

[Motorman_55792]

Sounds like a worn carb. What would be a needle jet in a Mikuni and made of brass is not replaceable on a Keihin and aluminum. The needle will over time wear that hole larger and make for a rich low throttle mixture. I had to go to a larger (leaner) base diameter needle on my bike with similar issue. Same needle with an "E" first letter in stead of the earlier "C" first letter. Now I could turn the idle down and adjust the air screw with results. A new carb is the real solution, but mine is a RB modded carb and I like it again with this change.

 

[icebergstu]

So....swapped out the Airstriker for a Mikuni TMXX38 from a 2011 Husqvarna WR300...

Wow...now I know why everyone falls in love with these bikes!!! Brilliant!!

Smooth, powerful and Linear from the bottom all through the rev range!

Love it.

Thank you to everyone who has helped out, it's so hard to diagnose a worn carb but we got there in the end!!!

Stu

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