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CV on 58 Panhead

Discussion in 'Other CV Performance products' started by PanEd, May 14, 2018.

  1. PanEd

    PanEd New Member

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    Hi,

    I’ve got a CV carb on my 58 panhead Harley. I’ve had it on the bike for about 7 years, but the bike was apart for the last 1 &1/2 years. When I first put it on the bike, it started much easier (important on a kick start only bike)

    Since I put it back together the cold starts have been difficult. Last time I rode it leaked gas from the air cleaner when parked. Since the only thing I didn’t do while the bike was apart was clean/rebuild the carb, I decided that it’s time to do so.

    The bike started well cold and hot before (and still does hot). The performance and MPG was not great, but still better than the stock Linkert. I would like to s see if performance and MPG can be improved.
    The motor is stock 74 inch with .030 pistons and stock FL cam. The air breather is a modified SE with K & N filter. The carb has a pressed on manifold adapter. Exhaust is true dual with Paughco 29" shark fin mufflers.
    Any advice you can offer, especially slide needle/emulsion tube recommendations would be appreciated.
    I can’t remember what size jets are in the carb, but will disassemble it in the next few days to find out.
    I live 30 miles from your Tampa Falkenburg road address in Zephyrhills, FL. Do you sell parts at that location?

    Thanks , RedPanEd
  2. PanEd

    PanEd New Member

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    took off and apart today, very dirty inside and out. will soak metal parts in simple green overnight.
    main jet is 175, pilot 45. no marks on needle.
    Carb part # 27504-96 (CA softail/FXR/Dyna)
    Last edited: May 15, 2018
  3. baggerpaul

    baggerpaul Well-Known Member

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    from your previous description sounds like your needle and seat on float were stuck!if gas was pouring from air cleaner . stick with the main jet and drop the slow speed jet down a bit for light throttle cruise area maybe a 42 if she gives ya trouble go back to the 45 .clean her up good and throw a cv performance rebuild kit in it .chances are no markings on needle at all .could be aftermarket ? got a pic of needleyou can post?
  4. hotroadking

    hotroadking Super Moderator Staff Member

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    I would imagine that cleaning it will help,
    get the insides clean, blow air through jets
    set the idle mix screw out about 2. 5 turns from
    bottom, and make sure the intake is sealed up.

    If gas was coming out of the filter like BP says the float
    was stuck open, you need to change the oil in the bike
    as well, if gas was running out the front you can be darn
    sure it was running down the intake into the intake valves
    and if the valves were open it was running down into the cylinders.

    4 qts of fresh oil is cheaper than a rebuild.

    If you are not running any vac off the carb be
    sure any carb ports are capped and that the caps
    you have are not cracked/weathered.

    I've seen where they look fine but when you took
    the cap off it disintegrated from the heat exposure.
    baggerpaul likes this.
  5. PanEd

    PanEd New Member

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    I'm sure once the carb has been cleaned and reassembled with new rebuild kit the leaking problem will be solved. The bike started easily before and I'm sure will again after reassembly. The slide diaphragm is pretty dirty, I'm not sure I can clean it without damaging it. I'm going to replace it with a new CVP slide assembly and slide spring.
    I'm posting some pictures of the needle , although they are not very good. No ID marks on the needle. The needle had pits or corrosion on it's shaft that I removed with Scotchbrite. I want to replace the needle, but not sure which one would be best.
    As I said in my original post, the bike started (and idled) good, but I'd like to improve the performance and MPG.
    Any advice would be appreciated.
    Thanks , RedPanEd
    2DSC02596.JPG 2DSC02597.JPG
  6. baggerpaul

    baggerpaul Well-Known Member

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    Looks like a stock evo needle shape.should work just fine in your application go through the carb replace all components in the rebuild kit and it should run fantastic!
  7. hotroadking

    hotroadking Super Moderator Staff Member

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    I'd just run that needle and setup, jets sound
    about right if it's starting easy and idles well

    Most non HD needles have a sharper taper
    allowing more fuel to get through the main
    jet when opening the throttle, few are designed
    to improve mileage, most power delivery.

    When you get it running you can turn the idle screw
    in until it stumbles, then back out it should smooth
    out, then as you go further the engine will stumble again.

    Mid point between the two stumble points is where
    you want to be. It should end up about 2.5 turns from
    bottom if the pilot jet is correct. Don't crank it down
    to the bottom, just lightly touch when turning it in
    to count turns from the sweet spot, you can damage the
    carb if you overtighten the screw.

    If you have to turn the screw out more than 3 to 4 turns
    to get to the sweet spot the idle jet is too small, if you make
    adjustments and it doesn't change or is 1 turn out the idle jet
    is too large.

    Heres a link on how to do it..

    https://cv-performance.com/harley_mixture_screw_tuning
  8. PanEd

    PanEd New Member

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    I'm going to replace the slide needle, which of the CVP needles would work best? Should I buy a stock needle from HD?
    Thanks, RedPanEd
  9. hotroadking

    hotroadking Super Moderator Staff Member

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    The needles CVP sell are the Velocity and N65

    Either would work, the N65 is a bit richer needle
    so it's going to provide a bit more fuel on acceleration
    which would nullify the MPG goal but help the performance
    goal provided the main jet is properly sized

    The velocity needle is a direct stock replacement...
  10. PanEd

    PanEd New Member

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    When I select the velocity needle on the CVP website it offers me 4 choices to select
    1. Harley Big Twin 1990-2006
    2. Sportster 883 1989-2006 or 1200 conversion
    3. Sportster 1200 1989-2003
    4. Sportster 1200 2004-2006
    Which one would you recommend I put in the carb for my 58 Panhead?
  11. kenfuzed

    kenfuzed Administrator Staff Member

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    Hi Ed, you’ll want to select the needle for the Big Twin Evo to match your set up.

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