06 flstc won't start

Discussion in 'Engine, Fuel and Exhaust' started by usmc1977, Mar 14, 2009.

  1. usmc1977

    usmc1977 New Member

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    Recurring problem but warranty is now gone. After the first winter the bike wouldn't start in spring. Would crank for a while, but wouldn't catch. HD took it in, replaced the battery -- although they said it continuously tested out ok. (side note -- this bike goes through turn signals, passing lights, even headlights like they're out of style). As I watched a mechanic replaced a tail light only to have it burn out as he was installing it! [and no, I don't take it in to have taillights changed! He was just looking into the electrical problem]) Anyway. Ran fine all summer, but as soon as the temp dips into the 40s in the fall it won't start. Even with a battery tender on it all winter it wouldn't start on the nice days. Bought a new battery (3rd one in 2 1/2 years) and installed it. Same thing. It cranks slowly. But won't start. Any suggestions would be appreciated.
     
  2. glider

    glider Veteran Member

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    I would suspect either a bad starter pulling the draw from the battery and lowering the volts available so the ECM will not fire the plugs or high resistance in the battery cables causing the slow crank.
     
  3. NEWHD74FAN

    NEWHD74FAN Experienced Member Retired Moderators

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    Here is one, bad regulator...output voltage is too high "cooking all the electrolyte out of the battery", premature burning out of bulbs is the clue. Damaged/depleted battery cannot crank engine under load plus maintain minimum 9-10V required for ECM to fire...! Same thing happens with "Flooded electrolyte batteries" low on water, boiled or evaporated out after long hot summer.

    Newer batteries are worse because more plate area, but less electrolyte & water, though sealed against tampering and made for evaporation, it still vents as maintenance free battery must use less water for low profile design...or go back to old style battery caps on top for user to add water. Imagine inside your battery only 1/8 full of electrolyte covering the plates...no time at all for 18-24V DC at AMPS from alternator/rectifier to bubble out what little water in a modern maintenance-free battery sponge plates dry in a short time, even your new one. Check the voltage with a DVM, it should never go over 14V or so even at 5,000 RPM. During and end of summer should check electrolyte level, and prior to storage after charging make sure it is at the bottom level mark...
     
    Last edited: Mar 14, 2009
  4. usmc1977

    usmc1977 New Member

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    But why would it be good all summer -- then go bad first sign of cold temps. And now the new battery won't kick it over?
     
  5. glider

    glider Veteran Member

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    Voltage regulators go bad at any time without much warning.
     
  6. Bud White

    Bud White Well-Known Member Retired Moderators

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    I go with a bad connection or cable ishould be drawing more power when cold .