Spark plug fouling

[Louis069]

Hi there hope you are all doing well.
I have a 2008 EC300 and been battling the jetting on this bike since i have owned it but think i have finally got it worked out. I have gone from:
-N1EF clip 1, 35 pilot, 175 main
To
-N3EG clip 1, 38 pilot, 175 main
so it is running much, much better and leaner, and im having a blast on it very powerful and tourqey.
I obviously had issues with the spark plug fouling at the start with the richer jetting

However i still havent been able to negate the problem fully, even with the new jetting. For example after spending anthing more than 15 minutes in woods singletrack and then exiting the woods onto a fire road and go to open the taps it will stutter/choke up before its gets to the powerband so i come off the throttle then on again and i will do this about 3-4 times before it clears itself out and will rev cleanly again.
Then this afternoon when i started it up, it went for about 5 seconds and before i could get the choke off it cut out. This is a photo of the plug after i took it out. Ended up putting a new one in and went 1st kick

I dont think it is running rich as the jetting seems to be on the leaner side. So all i can think of is reeds? spark plug cap? ignition coil?
I am running a BR7ES at the moment, as recomended by a former dealer in the area(linton at das, christchurch), he runs the hotter plug as he says that it is better suited for low rpm conditions. Not only that, thats what beta and ktm all use. He also says the BRP7ES with the projected tip can work better in some situations your thoughts? Im probably going to give it a go to see anyway.

Im running castrol power 1 2t at 50:1
Also forgot to mention it has had a new piston and rings about 10-15 hours ago.
Oh and i can still only get about 70km to a tank which is still double from what i used to get but not as good as some of you are getting.

Thanks very much for any advice you may have

[Doc Brown]

My personal opinion is that running a hotter plug is not the correct way to get rid of the plug fouling problem. Install the correct plug and change your jetting.

I am not discussing the N1EF as I think it is crap.

However, your clip position as well as pilot jet size indicate you try to solve a low down richness. Or why are you trying to lean out the mixture down low so much?

The N3EG is almost as rich down low (smallest throttle openings from zero to ⅛) as the N1EF. I also would not go lower than 40 on the pilot jet and choose a needle that is leaner down low (thicker starting diameter, like a NECW/NEDW). Maybe a JD kit would make sense...

[webmaster]

Install new needle - look for threads here or send message to jakobi for his setting as a starting point.

When you install the needle, be sure to reset your idle screw - it will need to be backed out for the low speed (pilot) circuit in the carb to become effective. With the n1ef needle, one will typically have the idle cranked in to the point of being "coil bound" and it still won't idle...

In this carb, you can go up to 2 1/2 turns out on air screw to get things dialed off the bottom.

With the jetting issue resolved you should see easier starting, better transition off bottom into mid/top and improved fuel efficiency.

Getting the head machined to dial in squish and compression can also yield high gains in both efficiency, ride-ability and power output.

jeff

[Louis069]

Originally Posted by webmaster

Install new needle - look for threads here or send message to jakobi for his setting as a starting point.

When you install the needle, be sure to reset your idle screw - it will need to be backed out for the low speed (pilot) circuit in the carb to become effective. With the n1ef needle, one will typically have the idle cranked in to the point of being "coil bound" and it still won't idle...

In this carb, you can go up to 2 1/2 turns out on air screw to get things dialed off the bottom.

With the jetting issue resolved you should see easier starting, better transition off bottom into mid/top and improved fuel efficiency.

Getting the head machined to dial in squish and compression can also yield high gains in both efficiency, ride-ability and power output.

jeff

Sorry didn't mean to cause confusion but I am running a N3EG needle now. I brought the bike with the bad n1ef.

However according to doc it sounds like this needle is still to rich off the bottom am I correct in saying that a N3EW or N3EJ would be leaner off the bottom as the last letter determines diameter, or did I make that up

Trouble is at the moment that needles are taking like 3 months to arrive. As ktm are getting them from Austria and Yamaha are shipping them by boat from Japan.

So at this stage I will have a look for some suitable needles and order another one or two to try out. Thanks for both your help

[tonyraft]

Go talk to Linton at D A S !!!!!!

[gg3]

Hi Louis,I have a JD Jetting 2010 model kit.It has the red & blue needle ,some main & pilot jets.If you get stuck I can send them down to try.

[Doc Brown]

Originally Posted by Louis069

Sorry didn't mean to cause confusion but I am running a N3EG needle now. I brought the bike with the bad n1ef.

However according to doc it sounds like this needle is still to rich off the bottom am I correct in saying that a N3EW or N3EJ would be leaner off the bottom as the last letter determines diameter, or did I make that up

Trouble is at the moment that needles are taking like 3 months to arrive. As ktm are getting them from Austria and Yamaha are shipping them by boat from Japan.

So at this stage I will have a look for some suitable needles and order another one or two to try out. Thanks for both your help

I am not so familiar with the N3xx needles, I prefer the Suzuki needles with NExx codes as they are super easy to understand. However, I could send you some needles for testing but I fear they'll take forever to get to you. I am in Vienna (Austria, Europe).

There are several ways to get rid of the bottom richness the N1Ex needles produce. Smaller pilot jet, yes, but not too small. I would not go lower than 40, maybe 38 on rare occasions. Dropping the needle to the top clip will have a positive effect down low but it has negative effects between about ? and ?.

So my approach is to use a needle with a longer and thicker starting diameter and put it in clip 3 and see how it performs in the first quarter of the throttle range. The air screw will help to fine tune. Once I have done this I test ride and see how the engine responds, always having the air screw position in mind. It should be between 1.5 and 2.5 turns out. My bike runs best between 2 and 2.25 turns out with a 40 pilot jet.

Maybe it makes sense to think about the offer from gg3. He is obviously in New Zealand too and you'll have the JD kit in a few days.

You are using a 38 carb, not a 36, right?

[(F5)]

If your bike has lots of hours maybe the needle jet has worn. They wear oval and nothing can fix that jetting wise
.
Take a viewing glass and strong light to inspect it. A Stix insert would fix that or a newer carb.

If it is ok then try another needle.

My 07 300 I have never ever fouled a plug. It just gets a bit soggy every year or two and I go, yeah? Wonder what the plug is like? Oh yeah. Rooted. New one. Sweet
But never ever fouls.

[Louis069]

Hi Louis,I have a JD Jetting 2010 model kit.It has the red & blue needle ,some main & pilot jets.If you get stuck I can send them down to try.

Thank you very much for the offer gg3. I have ordered a NEDW yesterday from a suzuki dealership and they said it should be get here today so i will see how that goes first, but if it still doesnt work out then i might take you up on that thanks.

Go talk to Linton at D A S !!!!!!

Yes tonyraft i did talk to linton and he was the one who reccomended the 38 pilot and hotter plug among a lot of other advice. He really can talk i ended up there for an hour lol

I am not so familiar with the N3xx needles, I prefer the Suzuki needles with NExx codes as they are super easy to understand. However, I could send you some needles for testing but I fear they'll take forever to get to you. I am in Vienna (Austria, Europe).

There are several ways to get rid of the bottom richness the N1Ex needles produce. Smaller pilot jet, yes, but not too small. I would not go lower than 40, maybe 38 on rare occasions. Dropping the needle to the top clip will have a positive effect down low but it has negative effects between about ? and ?.

So my approach is to use a needle with a longer and thicker starting diameter and put it in clip 3 and see how it performs in the first quarter of the throttle range. The air screw will help to fine tune. Once I have done this I test ride and see how the engine responds, always having the air screw position in mind. It should be between 1.5 and 2.5 turns out. My bike runs best between 2 and 2.25 turns out with a 40 pilot jet.

Maybe it makes sense to think about the offer from gg3. He is obviously in New Zealand too and you'll have the JD kit in a few days.

You are using a 38 carb, not a 36, right?

Thanks for the offer doc but you would probably be right about them not getting here, not in a hurry anyway. I actually threw the N1EF Needle out as the N3EG was way better. I ordered a NEDW yesterday which should get here today so ill se how that goes. Sorry forgot to mention im running a 38mm as1 carb

If your bike has lots of hours maybe the needle jet has worn. They wear oval and nothing can fix that jetting wise
.
Take a viewing glass and strong light to inspect it. A Stix insert would fix that or a newer carb.

If it is ok then try another needle.

My 07 300 I have never ever fouled a plug. It just gets a bit soggy every year or two and I go, yeah? Wonder what the plug is like? Oh yeah. Rooted. New one. Sweet
But never ever fouls.

Unfortunately i have no idea of the hours the bike has on it i know there were at least 2 owners before me. If i dont see any improvement from the new NEDW needle then I will take a look and see if its worn.

Thank you all for your replys very helpful

[(F5)]

Linton is the man if you want suspension done. Forks are pretty harsh for our conditions and deflect off tree roots. He has been evolving revalve for these.