N1EF w/#9 slide

farmerj

Platinum Level Site Supporter
I understand the lack of love for the stock N1EF needle, it can "blubber" (run rich) at 1/4 throttle or so and then when it cleans out, there is a "hit".

I tried to get rid of the lean spot by going down on the pilot, but then got a hanging idle. Coming down on the main leaves it too lean up top.

This diagram - which was very helpful - showed that at lower throttle openings (excepting the very bottom) the slide cutaway actually has more of an influence than the pilot jet.


Jetting pic.jpg


So I decided to that since I had a #9 slide in my '05 GG I might as well swap it out and give it a try in the 2018 (XC 300). Worked like magic!

FWIW the '05 carb was modified by Ron Black (RB Designs). He put a divider plate in that carb, and sent it back with a #9 slide. So there is some precedence for using the #9 in a 300.

I'm running 38/175/clip #2.

Bottom line -
Someone else needs to try the stock needle with a #9 slide and see if I am just imagining things. IMO this is a really good setup!

Jeff
 
I would expect better results too. Too thin a needle at the top will result in big harder to atomise blobs of gas being sucked past where they should have come up the pilot in a spray.
 
How the hell do you manage to get the GasGas airbox to fit around that? :rolleyes:

Is that why you had to bend that bolt in the centre?
 
I totally agree. There are not many people with a #9 slide sitting around, and you can get great results for less dollars.

At the same time I say that - I've had a well-jetted KDX, a good running '05 GG 300, and a Sherco with NECJ jetted almost to perfection (at least, my understanding of it!). This setup is better (for my riding style, etc.). But I must admit that I have yet to finish playing with the N3CH/N3EJ needles sitting in my jetting box.

I'm planning to be at a ride at the end of the month with a bunch of guys, so maybe I'll get a couple of them to give it a try - and take some time to tune the N3CH as a comparison.
 
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