2014 Gas Gas 300 - Jetting

[jpgibson]

dont know why, same thing happened with the 2010. didnt matter where the idle screw or as was. it also made starting a lot more difficult.

[MJC]

Originally Posted by n_green

Interesting, I was hoping the half clip leaner would allow it to come onto the pipe a tad sooner while retaining the bottom end torque.

The Yamaha/KTm N3xx series needles seem to work very well with a leaner slide. The #8 slide that I use really livens up the throttle response without sacrificing the lowend torque those needles provide.

[n_green]

Rode yesterday with the same jetting, 40p, AS1.5, N3CJ#3, 178m.
1100m asl, 12-22 deg C, 90% - 45% humidity.
Started the day trail cutting so putting along with a chainsaw on the back clearing fallen trees off an old track. Mostly 2nd and 1st slow speed. Temp at the time was 12 deg C and climbing, humidity started at 90% and was falling. The few times I did give it a bit power felt good, a little fat/doughy and burbly off the bottom but that's to be expected at the altitude considering it was jetted for sea level.
Came back at lunch, 27k's covered = 2.7l fuel. Not too bad.
Kitted up and went riding, 33k's of faster 2,3,4th gear single with the occasional techy hill thrown in. Temp was around 22-25 deg C and humidity had dropped to 45%.
Up top bike felt good, good overrev and power. Off the bottom I had good torque, still a tad fat but not too bad, after working it hard it idled up on occasion but never run on or got hot. Mid was a bit fat and doughy, and power suffered as a result, made it difficult to lift the front wheel over logs etc and powering out of corners it lacked balls. I could have/should have dropped the needle a clip to compensate for the altitude but I was lazy. Fuel use wasn't bad at 3.5l given I was fat through the mid.
This jetting is showing promise. As it starts getting cooler I'll either up the pilot or drop the diameter back to a N3CW.

[memphis2857]

Originally Posted by n_green

after working it hard it idled up on occasion but never run on or got hot. .

Not to hijack but, what causes this? My bike is doing the same and I thought it was the sign of a lean condition or an improperly set float? Other than this it feels pretty decent


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[n_green]

Originally Posted by memphis2857

Not to hijack but, what causes this? My bike is doing the same and I thought it was the sign of a lean condition or an improperly set float? Other than this it feels pretty decent


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Yeah slightly lean on the idle circuit (pilot/needle diameter) can usually be adjusted with the air screw. 1/4 turn in and it will most likely stop doing it, I actually prefer it this way as it cleans up the off idle response a tad too. It's not lean enough to bog when wacking open the throttle so no problems.

[BSM2]

Based on this and other topics I have put a N3CJ #4 needle in my EC300 2013.
Main 178, pilot 45, AS 1.5turns, sealever, 5-20deg.
As promised ;-). The bike runst great, great power and very strong at the bottom.

However it runs to lean (white plug) due the fact I race and 80% is between 1/2 throttle and wide open.
Which needle is reccomend for this use?
I'm thinking off N3CW, what do you experts suggest?

[Jakobi]

The W diameter will just provide extra fuel under 1/8 throttle.

N3EJ#4 will put you half a clip richer, or you could test from clip #5 as a crude test. But if it runs well from closed to 1/2 throttle and then leans off I'd simply bump up the main a couple of sizes. Its quick and easy, and you can go as fat as you need until it starts burbling at big openings.

[BSM2]

Hmm seems plausible.
So If I understand right, the needle hasn't any influence with half throttle to wide open. And I can just jet it right with my mainjet.
I love now the enormous bottom torque

[Jakobi]

Of course the needle has some effect, but imo its most noticable at around 1/4 throttle (via clip position), and then tapers and blends with the next circuit.

The other thing is that with current fuels, I wouldn't be too quick to jump into plug reading. There are a few trains of thought, but a general consensus is that you really need to do a plug chop to ascertain any level of detail. IE sustained throttle input for a period of time and then cease running and inspect the plug. The next area for debate is what to inspect. Some say use an oil plug, some say start new and read the fuel ring at the bottom (by cutting the threads away).

I personally jet by feel and response and keep an eye/ear out for symptoms associated with lean running. Flat unresponsive power which lacks the more you try to push. Pinging/detonation. Running hot/blowing coolant. Bike that runs better when cold and detorioriates as temps rise.

[BSM2]

Thank you al, have done some changes:
Rising the needle #3 -> #4
And pilot 42 -> 45
And the bike runs perfect now!
Good idle, good response, strong, lineair and a lot of torque at the bottom, but maybe a little bit to aggresive...

When opening the throttle just a view millimeters, it just hit hard to the arm and it is less manageable.
I love the bottom torque, but only from 1/8 - 1/4.
In my case I hope the torque input @ almost idle can be less.

Is there a needle recommandation to elliminate this?
I ride now with needle N3CJ at sea lever between 5-20deg.
Jakobi replied that N3CW needle supplies more fuel onder 1/8.
So i gues that is what i need?

Thank you al