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CV-Performance Velocity needles

Discussion in 'Motorcycle Tech Talk' started by NeilP, Feb 18, 2020.

  1. NeilP

    NeilP Active Member

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    Location:
    Jersey, Channel Islands
    A few years ago, 2009 ish, I bought the CV-P tuner kit for my Stage one basic upgrade to my stock 2004 883 Sportster.

    The kit as you probably know is needle, emulsion tube, jets. Also went with the V-Ductor, fuel,elbow, and Ez-Just mixture screw

    I spoke to Ken (via e-mail) a few times, and I told him I was going to be doing a 1200 upgrade at some point too, so he suggested which jets to add to my order, and also recommended their other 1200 needle.

    I did my 1200 upgrade about 3 years back..did the jets and forgot about the needle. Never Dyno'd the bike or did more than basic spark colour check....always did run a bit lean.

    The the 1200 kit rear pot (V-Twin manufacturing crap) had a manufacturing defect, it leaked oil from the head at the return oil drilling, about three fins down, so needed replacing, and the seller and V-Twin Mfg washed their hands of the problem, as I bought the kit (new unused, still boxed') off a friend. Still had original receipts etc but they would not help.


    So a few months ago, did a Hammer 1275 upgrade, head work, bigger valves, Andrews N4 cams etc.
    First AFR on dyno run was a bit lean so upped the Main jet from 185 to 190. Big lean 18:1 'lump ' on Dyno AFR at the start, but we did not have the jets or time to adjust that due to me needing to do a 300 mile run and boat ride to get home next day.

    A few pics...and I get to my question about needles below them



    [​IMG]

    [​IMG]


    So, a little weak at the start,
    I have a CV-P 45 idle jet in at present
    Have a CVP 46 and a Keihin 48 on order, so they should be here next week.
    Idle mixture adjustment using idle drop method, , bike stumbles about 1 ½ turns out when screwing it in. Screwing it out, it never idle cuts or stumbles due to too rich...so indicates needing a bigger idle jet.

    But ..now to my question about the CVP Veolcity needle.
    Currently fitted is the CVP Velocity 883 needle, and I found the bag with the needle Ken from CV-P ( and these forums? ) sent me for the 1200 kit.

    So I could not remember which needle was which. I guessed it was the 1200 needle but bag was not sealed and it was a few years ago ...like 10....
    The OEM Keihin Needle is labelled N9EY,
    The CVP needles do not appear marked with writing, but one had a circle on the head, one had a straight line on it..and it was in a bag with the CV-P sticker saying 1200X

    I wanted to check, so I e-mailed CV P tech ..and they got back to me saying ..NO...don't use the 1200X needle...
    Now I am confused...hence this question..
    .Ken who I understand is taking a back seat now, whose company it is recommended and sent me the 1200X needle for my 1200 upgrade, knowing it was going to be standard heads, yet the CV-P tech person is now saying ..don't use it.

    I am more inclined to believe Ken TBH...but he does not seem to answer e-mails anymore

    And what is the likely difference anyway? .they won't tell me the measurements so I can can compare profiles, or tell me where the Velocity 883 needle alters the mix compared to the Velocity 1200X

    I also have a Keihin N65B and N65C needles


    Yes..try them and see is one answer...but dyno runs not cheap, and the time taken to swap needles between runs is costing me dyno time at about $90 USD PER hour


    So, looking at the AFR, and hopefully you guys knowing about the needles...what is your recommendations.?

    Any one know where the CVP Velocity 1200X needle changes mixture as compared to the 883 CVP Velocity needle .? cV-P tech don't seem to know/ can't answer...

    .
    Last edited: Feb 18, 2020
  2. kenfuzed

    kenfuzed Administrator Staff Member

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    Hi Neil, so to start off I just want to let you know that I have not taken a back seat to anything involving my company. I wear many hats there and sometimes exchanging tech emails just doesn't fit with production or other administrative tasks on my plate. Anyone you correspond with at CVP under the Tech Support emails is either coming from a couple of others who I trust to give the same advice, or sometimes myself. I probably answered a couple of those emails myself (we get a LOT!). We also limit the amount of technical advice given since not being a repair or service shop it is easy for us to get sucked down a rabbit hole of diagnosing everyone's motorcycle. It's nothing personal, but as a manufacturer I've really had to limit our support to just how each one of our parts should perform, without getting too deep into tuning and repair better handled by a shop.

    So on to your question. The early lean bump shown I suspect is more related to the pilot jet, mixture setting, and transition between the two. It could also be a weak accelerator pump spray since that should be showing a richer dip when the throttle is first twisted. Clogged passages between the pilot jet, mixture screw, and the front air jet can certainly contribute to an early lean dip as well. Typically I have seen the lean condition carry on further into the powerband when it involves the needle. An early lean spike can also be caused by a slide that has been drilled out too big (> 7/64") since that could allow the slide to lift too quickly.

    My personal recommendation for the needle and your particular setup, go with the standard Velocity needle (the one with the circles on top) and not the XL2 needle (has a line etched across the top). The XL2 needle was designed for one purpose, the 2004-2006 XL1200 with stock XB style heads. Your bike has the 883 heads and even though they have been reworked it is very unlikely that they have the same flow characteristic that the 04-06 1200 heads did. Taking that a step further, even if you had XB heads and then reworked them, I would still recommend our standard Velocity Needle because the characteristics of that head no longer match that special needle. Lastly, I would not use the N65C or N65B, both have a straighter profile that might be good just off idle (what they were designed for) but you'll find yourself battling lean spots higher up the powerband.

    My recommendation for your build:
    1) Move up to a #46 pilot jet.
    2) Thoroughly clean out the passages.
    3) Verify your accelerator pump is providing a strong squirt, and be sure to replace your accelerator pump diaphragm annually (they crack over time).
    4) Use the standard Velocity Needle.

    Lastly, if I originally recommended using the XL2 needle I may have misunderstood thinking you had 04-06 1200 (XB) heads. I apologize if that information steered you wrong.

    - Ken
  3. NeilP

    NeilP Active Member

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    Location:
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    Hi Ken
    Glad you are still there. I got the impression you were still there ( but more back seat management role) due previous e-mail from one of your people and no of response to a Yahoo e-mail address I had from you from when I bought the initial kits from you back in 2009.

    I had the original bag with the 2009 order, might have been more than one order I can't remember now
    Date : 17 Nov 2009 - 01:18 Order ID : 1367916

    Other needle was in bag labelled 1200X. I have found your e-mail from then, where I ask about changing my order and you say

    So if i 'just caught you' I guess it was a rush to get me the parts before they went out.so see where the issue could have arisen. Not to worry.


    1) had a 46 and 48 on order already and arrived two days ago. Fitted 46 yesterday. Plugs look a little less white now, but no Idle RPM drop when backing out the EZ-just screw. might try the 48..

    2) did that yesterday too, and then squashed one the Accel pump little o rings..so reassembled and got a leak :(

    3) Accel jet it is supplying a squirt, but I was not so happy with it..which was why i stripped it down. So will be putting in an order for a new rebuild kit direct from you ..And probably your accel Pump nozzle too.

    4) I tried the 1200X jet yesterday. Seemed OK on road riding on the acceleration..but gave a caught/pop carb fart on very low cruse idle at 2000-2200 RPM at about 40 mph. Went back to the needle with the circle on top and the pop went away.


    I never drilled out the slide, it was left exactly as is..to your kit instructions. Think it mentions passing a 7/64 bit through just to clean the burrs ? Or whatever the size you recommend in the instructions would have been done. Since you mention it, I did wonder about the spring too. I have your shorter lighter spring fitted. Would that perhaps be allowing the slide to react too quickly ? so allowing more air in, before even the accel pump system supplies fuel? Is your accelerator pump nozzle/ jet a different size? or just a better nozzle profile..better atomisation?

    2004 bike wth original slide and diaphragm ? replace that too? or do the diaphragms usually last . it looks OK, sounds OK and seem to work.fine..got a 1993 bike wth 2500 miles to do too..maybe new slide assembly for that too


    Thanks for getting back to me...is your cv_carb at yahoo still active?
    Last edited: Feb 22, 2020

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