CV carb question

[baggerpaul]

Hello And good morning. Been a while since I have been on the forum .This question is for the grey beard fellows .Dug out some old parts and built the Dyna a fresh top end .had an old cv 44 and a larger intake to match .most of the time I'm able back in the day to leave factory needle and just ket accordingly. Seems this build is going to need a little richer needle and back off the main to a 210 or 215.went through my stuff and the only other needle I found was marked #NDKT .can someone confirm if this was a 44 or a 51 needle I looked through everything I owned cant find the needle part # list thanks in advance .stay healthy everyone.

[Baddyna]

If it says NDKT and has a total lenght of 2.718" its a CV 51 needle.   CV 40 and 44 needles are 2.253"

[baggerpaul]

From what I remember cv 40 and 44 were not interchangeable  44 were 3mm longer ? Thank you for the measurement!

[baggerpaul]

Yep this is cv 51 right on the money .with the measurement! Thanks again .seems that finding the needle is tough!

[JW113]

I'll leave how you jet it to you, but 210/215 main jet seems huge. What motor is this on?

These are the CV44 needles that I am aware of:

27727-99 #N8EK needle (leanest)
27933-99 #N8EL needle (lean)
27967-99 #N8EM needle (rich)
27968-99 #N8EN needle (richest)

The different needles are nice to have, but shimming the needle up works just as well. I got some small washers from McMaster Carr for this purpose.

-JW

[JW113]

By the way, if you do decide to shim the needle, here is what I use:

https://www.mcmaster.com/90945A713

-JW

[mayor]

I'll leave how you jet it to you, but 210/215 main jet seems huge. What motor is this on?

in a CV44?  doesn't seem huge to me.  I'm running a 226 main (custom drilled) in one 95" TW54 CV44 build and a 230 main in another 95" TW37 CV44 build.  I tried a 210 and 220 in both, just couldn't get the afr close enough in all ranges even with shims. 

[JW113]

Interesting. When I had a CV44 on a my 113", was using a 200 main and dyno'd at 127HP.

Like I said the first time, leaving how you jet it to you.

-JW

[mayor]

Carbs are like that.  Not every build takes the same set up. 

I tried the M needle in the CV44's, but ended up back to L needles in both my CV44 bikes.  Here's a thread I wrote almost a decade ago that covers street tuning my one CV44 build with a WEGO (updated last year to re-add the pictures lost to the photobucket fiasco):

https://harleytechtalk.com/htt/index.php/topic,26210.msg267218.html#msg267218

Still have that bike, and it still runs great. 

[Hossamania]

I'm running a 44 on a 95" with headwork and use a 250 main with the L needle. I've been all over this carb tuning wise, and this is what works best (46 primary jet, 48 too big). I would try a 260 main if I could find one, just to see what happens. I'm also running a higher rpm cam (Andrews 55) as opposed to a low end torque cam.
As mentioned, they're all different, hence, tuning.

[baggerpaul]

Ok build is as follows .crane 619 lift heads 1.940 1.605 exhaust .10.5.1 pistons .heads both chambers at 85.4 cc bassani road rage 2.5 inch baffle CV.44 .WITH A CV 40made 99.6 hp 104.torque .ran out of carb .cv 44 picked up 6 hp and like 3 ft lbs but it moved the power over to the left earlier and feels so much better everywere.only problem is in transition from pilot to main .if I had a adjustable air bleed I could cure this in an instant but that just isn't possible on a cv carb .some have had success with a long sportster needle and backing down the pilot without issiue on a 44 .or a nokk  needle as they are a bit longer .with this pipe and port work the velocity is very good in the heads .motor runs perfect at low speed and cruise at 80.mph on a 52 pilot air fuel at 13.9 to 14.2.with light throttle .idles at 13.1to 13.5

[baggerpaul]

Also with the 220 main it was rich at wide open falling to the 12.1 to and sometimes going into 11.7.air fuel so a 215 main cured that issuie.

[mayor]

Also with the 220 main it was rich at wide open falling to the 12.1 to and sometimes going into 11.7.air fuel so a 215 main cured that issuie.

with what needle? 

[baggerpaul]

Mayor that was wide open with n needle.my lean dip were on the air fuel ratio gauge and seat of the pants feel is also there .is transition from pilot to needle jet .you can see and feel the loss of power from 2650 to 2900 as soon as that slide starts to rise and main is starting to come on strong she will pull like a mule .only way to describe it like a two stroke starting to clear up .I have a few springs lying around .and last night for shits I grabbed one cut two rounds off just to see if it would change a bit getting the needle off the main seat quicker .and ofcourse it helps but you start to throw the rest of controlled air fuel ratio off in different rpm areas.might try to shim the needle and see what happens going back ofcourse with stock spring