Sporster not getting fuel to cylinders NEED HELP BAD

Discussion in 'General Harley Davidson Topic' started by 87sportster1100, Jun 13, 2014.

  1. 87sportster1100

    87sportster1100 New Member

    Hey guys,

    So I have an 87 sportster 1100 and bike was running great like a top always started right up, one friday night did a burn out with it then parked it the next day went to start it up it cranks and cranks and nothing. I have spark and I have fuel getting to the carb but when i pull the plugs after cranking it they are bone dry. i took the carb apart everything looks to be in order can anyone help me with this? basically its not moving from the carb to the cylinders i know there is a vacuum line on that side of the carb connected to some type of switch or sensor which has wires going back to my harness could this be the problem? I do not even know what this thing is, and i know the top of the carb when i took it apart it some type of diaphragm with a spring and the needle? i have no clue i cant figure it out and i want to ride who can help???
  2. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

    The vacuum line goes to a switch called the voes or vacuum operated electronic switch
    At a pre determined vacuum the switch will tell the ignition module to apply full advance and so aid acceleration
    The diaphragm in the top of the carb is the part that draws the slide up in the carb to increase the fuel and air mix
    When you open the throttle it turns a butterfly valve in the carb and allows more air to be drawn through the carb as the piston goes down in the engine with the intake valve open the suction is felt in the carb as a vacuum there is a small hole in the slide of the carb which passes the vacuum to the top side of the slide as it is sealed by the diaphragm the slide is drawn up to allow sufficient air fuel mix through the carb as determined by the position of the throttle butterfly valve the diaphragm needs to be correctly seated with no pinches for the carb to operate correctly
    Perhaps you need to check that the jets in the carb are clear and that the float height is correctly set also check the condition of the rubber tip on the float needle as it can stick and not allow fuel to the float bowl

  3. sportster 2001

    sportster 2001 Banned

    yea one at a time, start from tank.

    carb fuel bowl pump sucks a little from tank and that value ^^ mentioned closes the line if there's no suction

    so you got no fule, blocked tank (try put on reserve small chance diff inlet helps), bad tank value, or no suction by fuel pump (you have cv carb i assume)

    maybe you fuel bowl is empty (pump throttle pumps fuel in bowl). if you open up that nut that drains the fuel bowl: you'll know if that's dry when you pump the throttle (bike cold and off).

    i wasn't paying attention you said your sure fuel is in carb ?

    well either carb is clogged (go on youtube for carb cleaning video)

    or you have a good intake leak (suction+heat sucked out a hole in the seal?)

    or no vacuum is pulling fuel both cyclinders (hmmm unlikely). no vaccum could only be one or both valves frozen or blocked (ie carbon preventing exhaust from closing completely - that'd be no vacuum while starting i'd think. i wouldn't assume it's the worst thing first.

    anyway, a burn out could overheat and cause warping or damage. even if it goes well if it over-torques you get wear on bearings you'd rather not have - though harley has good ones.

    definitely don't get the bike hot do a burn out before it's warmed up or if it's too hot. that's a "performance / racing issue" you need to know a bit about racing and temperatures before doing it
    Last edited by a moderator: Jul 18, 2014
  4. lucky13c

    lucky13c Member

    could you tell me what kind of points your running? also i had a similar problem on my 89 sporty one of the circuits under the seat went bad spent a lot on parts before i found that. changed it out bike fired right up
    hope this helps
  5. dbmg

    dbmg Experienced Member

    I guess with no response from OP he must have got bike repaired for he has not responded since June 13...
  6. Breeze3at

    Breeze3at Well-Known Member

    Probably a "drive by". They post on a bunch of forums, then wait 5 minutes for a reply, or take bike to a shop. :newsmile016:
  7. dbmg

    dbmg Experienced Member

    You mean like a troll.........:bigsmiley14: