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Need to lean midrange

Posted: Sat Mar 19, 2011 7:25 pm
by Indiana Jones
Just back from the dyno.
My plug and play RVF ram air setup gave me 40bhp.
Something not right.
Not happy,seriously thought the timing was way off until I lobbed on my old NC30 HRC spec carbs.
66bhp with a seriously rich needle/mid range.
I'm running 8ZG(lean afaik) needles with no shim and 142.5 front,145 rear MJ's.
WOT fueling is fine.
Need to lean out the needle.
My options are very limited.

I'm considering running the stock needles with a shim to richen the stock lean spot,and hopefully lean my fueling coming onto the MJ.
Or reduce my air jets to a smaller orifice(already restricted),and drop my MJ a size or 2.
More dyno time rather than a track day tomorrow,I think.

I found a very useful "needle thread" with the needle comparisons.
Anyone running the stock needles in this manner?

Re: Need to lean midrange

Posted: Sun Mar 20, 2011 4:51 am
by Cammo
What sized pilot jets are you using?

Re: Need to lean midrange

Posted: Sun Mar 20, 2011 10:05 am
by Indiana Jones
Stock pilots

Re: Need to lean midrange

Posted: Sun Mar 20, 2011 10:30 pm
by Cammo
No easy option then.

When you say midrange, what revs is it rich at? Is there a chance that you won't be using this midrange on the track?

Re: Need to lean midrange

Posted: Mon Mar 21, 2011 12:27 am
by Indiana Jones
Around 6k it starts getting rich.
Way too rich coming onto the MJ.
I've restricted the air jet back to 2mm from 2.5 and dropped the MJ's back a size to 140f 142.5r
Man,those NC30 carbs make a racket on the pipe,nice.
Getting some info on my ramair setup,so hopefully get that sorted too.

Re: Need to lean midrange

Posted: Mon Mar 21, 2011 12:34 am
by Cammo
indiaguy wrote:Man,those NC30 carbs make a racket on the pipe,nice.
Yeah, I like them. Mine has strong power, very nice.

FWIW I use the 8ZK needles which are the leanest.

Re: Need to lean midrange

Posted: Mon Mar 21, 2011 7:35 pm
by Indiana Jones
And where would a lad find some 8ZK needles?

Re: Need to lean midrange

Posted: Mon Mar 21, 2011 9:58 pm
by Cammo
I got mine from yahoo japan, but I haven't seen any for sale in a while.