NC30 A/F screw position

emto · Post by **emto** » Thu Sep 17, 2009 11:33 am

I've just raised my needles by 0.5mm and drilled the slides and happy with the results so far. However, the revs seem to be "hanging" a bit on closed throttle and take a while to settle back on idle. Should I open out the A/F screws further or close them in to cure this? They're currently set at 2.25 out, 118f/120r jetting with I/2 Ethos system, new std air filter & carbs properly seated.

Post by **J.B.** » Thu Sep 17, 2009 12:50 pm

If the NC30 is the same as the NC35 then the mixture screw adjusts air, so opening it will lean the idle mixture & closing it will richen it - someone will confirm this I'm sure. If the revs are "hanging" when you close the throttle it can be a sign the idle mixture is too lean. They may be dumb questions but ... are you sure you seated the diaphragms properly when you re-installed the slides? Are the slide springs OK etc? How big are the holes you drilled in the slides?

Post by **viper_biker** » Thu Sep 17, 2009 12:57 pm

RVF and VFR a/f screws work in the opposite way to eachother. My bike ran a similar set-up at one point in the past, but I ran bigger jets and it was too rich. My settings were,

120f - 122r
2.5 turns out on A/F
0.5mm shim
HRC modded air filter
No snorkel on the airbox
HRC scoop
Drilled slides (but this doesn't effect fueling)

Post by **Neosophist** » Thu Sep 17, 2009 3:42 pm

Thats a typical 'lean' condition.

Providing you have no air-leaks (which would lean your mixture out) try resetting them to 1.5 turns out and start from there.

Scratch that I thought you were on about an RVF (35)

Turn your screws half a turn in whatever direction richens the mixture :)

Post by **Cammo** » Thu Sep 17, 2009 11:19 pm

Neosophist wrote:
Turn your screws half a turn in whatever direction richens the mixture :)

That's 'out' on the vfr. In will make the setting leaner.

Post by **Neosophist** » Fri Sep 18, 2009 1:14 pm

Stickshift wrote:
Neosophist wrote:
Turn your screws half a turn in whatever direction richens the mixture :)
That's 'out' on the vfr. In will make the setting leaner.

Good good, I thought it was, just wasn't sure :D

Post by **911f** » Sat Sep 19, 2009 5:37 am

can someone verify what has been written above. will benefit someone searching down the road like I did recently. I read both ways for the NC35 - that its air and that its fuel being adjusted with the A/F screw. I had understood it was fuel - thus out was richer. Is there anyone out there that knows definitely which is which for the NC35 and 30?
thanks

emto · Post by **emto** » Sat Sep 19, 2009 12:19 pm

Thanks guys, will let you know how I get on.
By the way 911f, it appears out will richen on a 30 and in on a 35.

NC30 A/F screw position

NC30 A/F screw position

Re: NC30 A/F screw position

Re: NC30 A/F screw position

Re: NC30 A/F screw position

Re: NC30 A/F screw position

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Re: NC30 A/F screw position

Re: NC30 A/F screw position