Bike only runs with choke on???

Discussion in 'Engine, Fuel and Exhaust' started by Wtlj, Aug 16, 2012.

  1. Wtlj

    Wtlj Member

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    I just got my 2003 sportster yesterday. Tonight I changed the oil & filter, spark plugs and removed and cleaned the carb. The bike runs at idle excellent with the choke half way out and dies when the chokes off? Do I need to adjust the idle? If so how do I do that? Also when riding it around the block after the maintenance there was a loud popping noise a few times is that something to worry about.
    Thanks in advance
    Terry
     
  2. BUBBIE

    BUBBIE Well-Known Member

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    Terry,

    Did the bike run good Before you tore into the carb?

    IF so, it sounds like you did something to the float level (too low).

    The bike has a Choke marked Knob, but it is an Enricher not a choke, just so you understand. It doesn't choke off air but adds gas to the mix...

    So some how you are really lean and the noise Might be just that.

    Properly low jetted,,, the idle screw will be out 1.5 turns...

    Don't seat it in Hard, That will ruin it...

    The idle jet is not your problem as you say the enricher has to be out 1/2 way.. That is a real shortage of fuel and Not getting to the engine.

    Give some more informtion : did it run good before and blabla bla a little more about the problem and When it happened...

    The carb is really simple and Might just be a too low a setting on the float level or Dirty jets... Not leaving out a bad air leak into the motor around the carb intake gasket or the intake manifold gaskets.

    The Popping noise is probably the enricher out and Lack of fuel thru the carb or too much...

    signed....BUBBIE
     
  3. Wtlj

    Wtlj Member

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    Wow! Thanks Bubbie for taking your time to help. I was given this bike from my uncle which hasn't run it much since last season. It runs a little better than before I did the maintenance. When I push the "enricher" all the way in it dies if i don't have the throttle turned. The carb looked very clean when I took it all apart tonight but I did a thorough clean except 1 screw I didn't have a driver small enough to fit. I also put everything back to how it was.
    Terry
     
  4. BUBBIE

    BUBBIE Well-Known Member

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    Were you sure that you didn't Pinch the Diaphram IF you had it apart???

    That is easy to do and IF damaged ( pinched or a hole) it will Not run properly...


    NOT using the enricher out after warmed,,,,,,,,,
    IF it will run at a fast Idle with the Throttle turned JUST a little on,,, it might need the carb MAIN idle screw,,, in by the throttle linkage top side, turned IN a little to increase the idle speed...

    Try that first...

    Sure sounds like a big shortage of fuel from here.

    If running fast, does it Still need the enricher (choke knob) out to do so.?

    Do you have a book for that year sportster? That would always help...

    On the bottom of the carb is a little round lead plug that covers the Idle adjusment screw... IF not open (pry or drill to grab it out CAREFUL of the threads that run from the bottom sides of hole to the adjustment screw) then you can take a small straight bladed screwdriver to adjust that... Always turn it IN and NOTE how far in it turned to LIGHTLY seat... Then go out to 1.5 turns andd warm the motor then Adjust it to run the smoothest and fastest idle...... Then adjust the top Idle adjuster so it runs at about 900 rpm
    (no less)(fast idle)..

    Enough for tonight...
    see your report tomorrow...

    signed....BUBBIE
     
  5. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

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    Just a couple of thoughts on this perhaps the screw you could not get out was the slow jet as it is deep in a housing that i at first found difficult to get in to if it is blocked you may have the sort of issue you describe
    also if the carb is not fitted correctly on to the manifold a wee bit of air being drawn in there would cause a weak mixture i always give the carb a twist in either direction to get it to seat correctly it can be a bit of a pest

    Brian
     
  6. Bodeen

    Bodeen Well-Known Member Staff Member Moderator Contributor

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    There are a ton of articles and pictures in the self help section. Without the manual, i suggest you start by doing some research in the self help section.
     
  7. cool breeze

    cool breeze Active Member

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    slow jet partially clogged
     
  8. BUBBIE

    BUBBIE Well-Known Member

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    Like fin and others said:

    This takes a small straight bladed screwdriver to remove the Slow Jet... Like cool breeze and fin_676 said .... This may need some carb cleaner as it could be the major problem.. Careful to remove so you don't ruin the brass head it Can shear off and You have a Major problem (fit screwdriver carefully). This slow jet Looks simular to the Main jet that you see on the main fuel center tube but smaller and has a short tube with holes along sides for the fuel.
    More than likely, Maybe the problem...

    I always take the 4 screws out and replace them with allen headed 5/8 long Metric threaded screws... Makes for easier float bowl off when carb is on the bike... NOT tighter but Easier,,, phillips and I don't get along:small3d002:

    Make sure the little gas squirter arm is In Place on the carb float bowl... easy to forget and leave dangle to get lost.. This excellerator arm is necessary to give a shot of gas into the carb when the wrist is turning the giddy-up:D

    signed....BUBBIE
     
  9. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

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    As Bubbie said replace the float bowl screws as the soft brass Phillips heads seem to disintegrate at soon as they see a screwdriver
    M4 x 12mm socket head screws are the ones to look for

    Brian
     
  10. Wtlj

    Wtlj Member

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    You guys are great! I will replace the screws. When I did the carb clean everything was already really clean. I have a service manual on order from HD but it's back ordered. I need to find a schematic of the carb so I know what's what. So I should remove the carb again correct or can I do all the cleaning and adjusting by removing the float bowl while still on the bike. Bubbie do you know where I can find a blow up diagram of this carb?
    Terry Leo