Help me get my Air/Fuel mixture right! PLEASE!

[vfrman]

I'm going out to the garage right now to tear into this. I'll drag the SLR out with me to take some good pics. I really think it is the mains...I am at 5500 feet after all.

[vfrman]

OK. So there was a bunch of crud in the fuel tank...so I drained it and cleaned it out. It is drying now...hopefully it will be GTG tomorrow. Good news is the inside was not rusty.

While I had the carbs off I shot a pic of the intake throat and valve stem. Clean as a whistle.




I also shot a pic of the float chamber...also super friggin clean...the pic is before I cleaned them.



Here is the only bit of crud I found on the float filters.



I even pulled the plugs and cleaned them off...
Here is the front (they both looked the same)


And the rear...


Both were taken before I cleaned them. There is oil all over the front two plugs

So now I don't know why the af ratio was so wavy. Maybe they ran it with the fuel tap closed? It was closed when I fired it up to load it back into the trailer. I would think it would have stalled in that case. I haven't done the HRC mod to the tap and when in the off position it cuts fuel off. FIIK what is going on.

I put the 108/112.5 jets in it and I'm going to take it back for another run to see how it is.

[Neosophist]

Mains dont do that much low down though, you could put 260s in there the needle taper will control how much fuel comes out until the needles are out.

I think itll definatly lean out the top end but not sure about the rest of it.

yours looks super rich all the way though, odd.

See how you go with that anyway and post back

I had mine dynod about 12 months ago now, ill see if I can dig out the graph and get you a picture, by no means a perfect example but it pulls clean from idle to redline with not flats. I seem to remember it being a tad lean low down

[Cammo]

Steve - I know that Rick O has a poor opinion of the factory pro needles (if yours are), I'd avoid using them if possible. They probably won't be helping your issue.

This is an old tuning article by Rick (circa 2000?), but still relevant today: http://www.akhara.com/nc30/nc30manuals/ ... Oliver.pdf

[slo12]

118/120 and still rich at 4400 feet

[vfrman]

And those are the same jets I was running at 5500 feet. I have the 108/112.5 mains in there now, so we'll see what they do on Saturday. If it's close I'll just do the track day on Sunday and then look at HRCing the shit out of the carbs this winter...

[Tornado]

How did the dyno run go? Did you get this issue sorted?

[vfrman]

I changed out the mains and it pulled pretty well at higher RPM. I couldn't get it back to the dyno, but I did do a plug read and it is still a tad rich. It is a track bike and the season is over, so now I am at a crossroads...do I get this sorted with stock setup or do I go all in and HRC the carbs...decisions, decisions.

[RickOliver]

Steve - I know that Rick O has a poor opinion of the factory pro needles (if yours are), I'd avoid using them if possible. They probably won't be helping your issue.

This is an old tuning article by Rick (circa 2000?), but still relevant today: http://www.akhara.com/nc30/nc30manuals/ ... Oliver.pdf

That is a very old article and really needs some drastic updating.

FWIW, I would say that the silver needles in your picture are Factory Pro and the gold ones are FI. I still have the same FI needles in my NC30 that I fitted 10 years ago and they work very well. I run them with the circlip in the 3rd groove from the top and just the stock washer underneath, no extra shims.

Rick