Gas Gas Ec 300 2004 Carb setup issue

J

JayStallion

New member
Hi all,
Long time no see, I'm finally there I have managed after 5 and a half years (on and off) to build from scratch a ec 300 2004 bike.
I posted some of my build video YouTube links on here a while back and got a mixed response, anyway I'm not here for that I've come into an issue with the bike.
I fired her up for the very first time last Friday I put fresh petrol in fresh oil etc etc. The engine was completely rebuilt so this was a first for the engine.
All was well with that I mean I kicked and kicked and kicked and she burst into life I was revving away with a s**t eating grin on my face but as I let off the throttle she did not idle so I researched and set the air screw to factory 1 and a half turns out (brass screw) kiehin pwk 38 carb. I fired her up again adjusting the air mixture pilot screw (plastic screw) to no joy. It stayed idling for the longest time although very low and died after 15 or so seconds when the air mixture screw was fully in.
I did some more research and found out that adjusting that screw even minutely should change the revs, but mine didn't it didn't change a thing no matter how far in it was or out.
I've been having a play today and had the air screw 2 to 2 and a half turns out and the idle screw 4 turns out had it idling for 20 to 30 seconds but then died.
I researched some more and had a look at the jets the carb had in them, I found,
Pilot jet 42
Main jet 180
Jet needle on 3rd notch (guessing factory needle)
When I looked in the 2004 manual the standard settings are
Pilot jet 35
Main jet 185
Doesn't say anything about the needle as in notch position
I've had a look at the spark plug and is was a little black so after researching it's running rich, so I have ordered a 35 pilot jet thinking this will sort my issue out.

My question is am I on the right lines in thinking this is the right thing to do as it will lean it out being a smaller jet?
Also looking on the data base alot of people on here run there bikes with a 42 idle jet??
Any advice, any help will be much appreciated
Thanks in advance
Jay
 
You need to find out what needle is in it the stock one is junk 1nef something I think.readthe getting sticky
 
cbutler said:
You need to find out what needle is in it the stock one is junk 1nef something I think.readthe getting sticky
Click to expand...

Hi thanks for the quick reply. How do I find out what needle is in? I took the carb apart and the needle had no markings on it? What needle should be in and doesn't the needle contribute to 1/4 throttle - 3/4 throttle? Sorry if that's wrong I'm new to enduro but eager to learn. I'm still searching threads to see if I can find any info that may help with my idling issue. I probably should of mentioned the bike sounds sweet as through the revs no bogging or mis firing if that helps. Cheers again ��
 
So when you pull the needle out it should have the code on it. If it is brass coloured with no code on it it could be an aftermarket one.

If it is actually a N1FE that is std. Cut it in half so you are not tempted to use it.

Go to the jetting threads and research what is best for your AS1 carb/ bike.

Once warm mine will idle a bit but not forever, who cares? Needs to be run through the gears before it runs clean. This is because the petrol atomises better on warm metal but mainly the petrol that was in your carb has had all the light end gases evaporate since you rode last month.
 
(F5) said:
So when you pull the needle out it should have the code on it. If it is brass coloured with no code on it it could be an aftermarket one.

If it is actually a N1FE that is std. Cut it in half so you are not tempted to use it.

Go to the jetting threads and research what is best for your AS1 carb/ bike.

Once warm mine will idle a bit but not forever, who cares? Needs to be run through the gears before it runs clean. This is because the petrol atomises better on warm metal but mainly the petrol that was in your carb has had all the light end gases evaporate since you rode last month.
Click to expand...

That's interesting, so the stock needle is not very good I take it. I'm excited to actually ride it for the first time like properly go through the gears and see how she goes, I did think I needed to do that to properly get it up to temperature and see if that would sort my idling issue.
Thanks for this reply I'm going to be able to try this method in 2 weeks and hopefully I should get a better feel of how the bike is responding through the gears and revs.
The 35 pilot jet comes tomorrow so going to give that a whirl and see what happens unless there is a reason why I shouldn't? Sorry just re read your reply yeah pulled the needle fully out and is brass with no markings on maybe it is an aftermarket it was already in the carb that came with the bike in a box stripped into to pieces frame,engine,folks everything. The guy my father in law bought it off blew the top end, took it apart excessively and couldn't put it back together so sold it him, lucky me great Xmas present lol. Cheers again for the reply
 
35 pilot jet just arrived I also got an s3 adjusting air screw to make adjustments easier. Thanks for all the replys I will be trying the new jet out tomorrow and report back.
Just a quick question for the tension on the throttle cable am I right in thinking a little bit of play on the grip and fully closed in the carb ready for adjustment using the pilot air screw ?
 
Results of the day....
So I changed the pilot jet from 42 to 35 reset air screw to 1.5 turns out and set the idle screw to 2.5 turns out. The bike ran for 15 seconds at a nice idle but then died, I was unable to get her going again so adjusted the idle screw and air screw to get the bike idling at very low revs. In the end the idle/pilot screw was all the way in (seated) and the air screw was 2.5 turns out. As I went through the revs I noticed thick smoke coming out of the exhaust so I adjusted the jet needle clip to 2nd from top notch to lean her out also tried top notch and both results was very simular not as much thick smoke but not the same thin smoke when idling.
What else can I do ? I've been doing loads of research and the idling should be higher, mines on the brink of cutting out.
I thought the 42 pilot jet was making the bike to rich to idle, now with the 35 the idle screw is all the way in which I know in for rich out for lean.
Would it really make a difference swapping the pilot jet again and trying a 38 or 40?
As I've tried many different adjustments to very little joy could there be something I'm missing ? And no matter what I do with the jetting something else needs sorting first?
I've adjusted the float to precise measurements so that's bang on. I have a cleaned the air filter washed and re oiled and got clean petrol mixed with 2t oil at 50:1
Please can some help me and maybe give me some advice that will give me hope that I can get this 5 and a half year build complete.
 
I'd try the 40 or 42 and once fully warm get it to idle for 5 seconds and stop testing concentrating on how it runs.

180 is huge main. Try 175.
 
(F5) said:
I'd try the 40 or 42 and once fully warm get it to idle for 5 seconds and stop testing concentrating on how it runs.

180 is huge main. Try 175.
Click to expand...

I'm getting a jet kit 10 pilots 10 main all different sizes delivered next week so I will try your recommendations
Thanks for your advice ��
Just out of curiosity what jets do you have in your ec 300? I know 1 setup doesn't fit all I'm just wondering
 
What needle is in there? Read the jetting threads and get a good grasp of what adjustment does what. A 35 pilot is way too small for a AS1 carbed 300.
I had that exact bike and it would idle all day long on a 45 with a N3EG needle second clip and a 178 main. Never fouled a plug either.
That stock needle is rubbish if that is what is in there.
 
JayStallion said:
I'm getting a jet kit 10 pilots 10 main all different sizes delivered next week so I will try your recommendations
Thanks for your advice ��
Just out of curiosity what jets do you have in your ec 300? I know 1 setup doesn't fit all I'm just wondering
Click to expand...

I think I had 175 or 172, with original but I've got a newer carb on it now as mine got needle tube damage from some grit. So I'm 170, but that's another story.
 
Gasser Nate said:
What needle is in there? Read the jetting threads and get a good grasp of what adjustment does what. A 35 pilot is way too small for a AS1 carbed 300.
I had that exact bike and it would idle all day long on a 45 with a N3EG needle second clip and a 178 main. Never fouled a plug either.
That stock needle is rubbish if that is what is in there.
Click to expand...

Not sure what needle is in the carb, it has no markings on it and is just fully brass. As soon as I can I'm going to change the jets to the recommended settings. There was a ton of thick white smoke kicking out of the exhaust after changing the idle jet to the 35 but I know that shouldn't have anything to do with it when doing through the rev range. I've been looking for a place to buy needles from but struggling a little bit to find anywhere in the UK. Thanks for your recommendations I will post my results probably this weekend
 
If you do not know what the needle is put it aside and fit one of the recommendations. A new needle from either Suzuki or a Ktm dealer is only about $10-20 Australian. So stuff all. Well worth the hassle of finding one.
 
Gasser Nate said:
If you do not know what the needle is put it aside and fit one of the recommendations. A new needle from either Suzuki or a Ktm dealer is only about $10-20 Australian. So stuff all. Well worth the hassle of finding one.
Click to expand...

OK so I've found a UK based ebayer who's selling a N3EG needle brand new from yamaha warehouse it is for a yz250 1986. Do you think this will fit my carb, like I say it does say it is a N3EG needle.
Thanks so much for your help, I guess I can order it and return it if its not right
 
JayStallion said:
OK so I've found a UK based ebayer who's selling a N3EG needle brand new from yamaha warehouse it is for a yz250 1986. Do you think this will fit my carb, like I say it does say it is a N3EG needle.
Thanks so much for your help, I guess I can order it and return it if its not right
Click to expand...
should work. I think it is also used in ktm's
 
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