High speed problem

Discussion in 'General Harley Davidson Topic' started by jm2005gt, Oct 16, 2012.

  1. jm2005gt

    jm2005gt Member

    Hi guys, I have an unusual problem which seems to be difficult to identify the root cause of. The bike in question is 2002 FLHT with an 88, it has 203 cams stage 1 kit with V&H pro-pipe.

    When riding at higher speed, (75-80) the engine will act as though it just ran out of fuel, but if I let it slow down a bit it runs normally again.

    I can make the bike do it as well in 4th gear at approx 65-70 mph it seems like its running out of fuel at higher RPM when there's a load.

    I can hit the rev limiter in 1st through 3rd with no problem.

    I've had the carb redone with no change.
    Checked exhaust baffle for issues.
    New Plugs.
    Cleaned and checked air cleaner.

    The bike runs just fine below that speed, but its terribly annoying when riding 2 up in KY with a 70 mph speed limit and needing more throttle to climb a long steep grade and having the bike die. (actually it never stops running, just drops like a rock to 65 mph or so.

    Any suggestions would be greatly appreciated.
  2. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

    To me it seems that you are not getting sufficient fuel for higher loads this could be due to incorrect setup of the carb, badly routed or pinched fuel line, blocked in tank fuel strainer
    If the carb has been checked and you have the correct jets for your upgrades to fuel and air
    the float height needs to be correct to allow for the delivery of the fuel at higher loads
    remove the fuel line and check it also remove the fuel tap from the tank and check the state of the strainer that sticks into the tank

  3. Breeze3at

    Breeze3at Well-Known Member

    I think Fin has you on the right track. Pull the fuel line off at the tank and turn petcock on (with a catch can of course), it should flow full stream from the tube. If that's good, go downstream and check that it's flowing into the carb. full stream. If flow is weak, pull the petcock and clean the micro-screen. If the flow starts strong, then slows down, you may have a clogged tank vent. If everything flows well, then your problem is probably in the float setting.
    The same advice Fin gave, I just use more words.
    Last edited: Oct 16, 2012
  4. Mongo1958

    Mongo1958 Junior Member

    Answer: Seafoam
  5. jm2005gt

    jm2005gt Member

    Thanks guys will give it a go.

    BUBBIE Well-Known Member

    If your fuel petcox is stock, there is a Safety Vacuum line from IT to the carb...

    You need to apply a little Vacuum (mouth suction workes for my carbed bike) to get the line that goes from the petcox to the carb to Flow Gas. Your bike is not running to do the fuel line Flow thing-E.:D

  7. Bodeen

    Bodeen Well-Known Member Staff Member Moderator Contributor

    Which also needs checked, if you are losing vacuum you will lose fuel flow. Check the vacuum line real good for cracks and such. The diaphragm inside the vacuum actuated petcock is also susceptible to ethanol fuel eating it up.
  8. Jack Klarich

    Jack Klarich Guest

    You say you had the carb re done and no change, so we can assume this problem was already there? Follow the advice here and check your petcock and vacuum hose, check the tank vent and crossover and cap also