1994 vfr 750 not charging

Discussion in 'Mechanics Garage' started by dougdowney, Apr 4, 2016.

  1. dougdowney

    dougdowney New Member

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    this is blowing my mind that i cannot figure this out yet..... i installed a new stator. rectifier. rectifier pig tail. and load tested my battery.. which is 13v at like 230cca...... with a full charge battery reads 13v like it should. while idling it runs at 11.8 without a voltage decrease. with the stator disconnected it runs 12.5v with a slow decrease(duh). im running out of ideas here if anyone has any input please feel free to give me your constructive criticism. the bike literally runs perfect. minus the battery voltage... it was moderate last year running at 13.2v on my volt meter i installed and all of a sudden it dropped and wont function like it used to and i refuse to take it more then a few miles away from my house with it in this condition.
     
  2. squirrelman

    squirrelman Member

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    Pull the plug off the top of the starter solenoid and inspect its underside as well as the connections on the solenoid. Any melting, burning, or discoloration in there will reduce charging.
     
  3. skimad4x4

    skimad4x4 "Official" VFRWorld Greeter

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    Hi Doug - Ok I fear I should be referring you straight to the infamous "drill".

    But you can do some basic tests just with a simple DC volt meter connected across the battery terminals. So charge the battery and measure the volts (disconnected), then connect it and measure again. Start the bike and measure volts at idle and then again at 5,000 rpm. Take bike for a 20 minute ride to get the electrical components good and warm (stay local in case it starts messing with you) then swiftly repeat those measurements.

    If the battery is healthy the battery disconnected and connected should be virtually the same - between 12.7-13.2 volts. Normally a healthy stator and RR should be delivering 13 - 14 volts+ at idle and between 14 and 15 volts above 2,000 rpm. It should never exceed 15.5 volts or things like headlight bulbs will blow. (Lights on/lights off should make no more than about 0.5V difference to those numbers.) If the numbers fall outside that range, you need to do the drill - see post #9 in this thread and post up the results if you need help figuring out what component(s) need attention.

    http://vfrworld.com/forums/showthread.php/39277-How-to-fix-common-regulator-Stator-failures

    Help - this is probably irrelevant but I recall some of the early 750's had issues which were traced to an "orange connector" which is taped up and hidden in the loom. Someone - maybe "zoom-zoom" posted pictures showing its location, and it just might be worth checking if the same connector is problematic on your 750.

    Take care - let us know how you get on.



    SkiMad
     
  4. Knight

    Knight New Member

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    Dougdowney, what events led to the replacement of these components?

    Are these OEM or aftermarket components? Yes as part of the drill test the new stator, the impedances across the stator terminals and the voltage output at idle. Any surprises there?

    Leave the bike sit for a while to discharge. Put the voltmeter on the battery and start it up. What is the very first idle reading? Does it change or is it a solid 11.8V? A slow drop may point to a bad ground as Skimad is alluding to. There may still be a bad ground, this is just a possible indicator. As the ground side of the bike gets energized over time, the voltage between positive and ground will slowly decrease.
     
  5. dougdowney

    dougdowney New Member

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    i really appreciate your input guys. ive tested the components. now what i figured out was pretty much nothing lol.... so i swapped out the rectifer again.. bam 14v volts working like a dream. i was so excited so i put it together took it on a test run... 60 miles it was perfect... came out to ride it again today and bam right back to having the no charge issue.. so im back to the drawing board again.. the only thing i have found so far that im going to be changing is my starter relay connection is pretty much toast.. melted and all that good stuff. im not sure if its going to fix my problem but i figure i solder in a new pig tail just so it doesnt cause issues later in the bikes life. but what its seeming to me is that maybe im having a harness shorting out issue. because everything gets hotter then i would like it to be quicker then i would like it to be. i understand the systems runs hot in the first place but this seems abnormal...... as for components i have a ricky stator rewind. i refuse to dish out the 350 my local honda dealer is trying to charge me for oem. rectifier is also not oem. i understand how much its reccomended but i ran this rectifier for 14xxx miles before this issue showed up. and then an additional 60 last night after i resorted to putting it back on the bike in fear that the other replacment was the wrong one.
     
  6. RVFR

    RVFR Member

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    From the get go, I was going to throw out that you could have a short in the wire harness. Knight brought up some good thoughts too. only way to know for sure is ,one, strip up the harness or two, get an ohm meter and check out each wire. but like said by squirrel the starter relay can play a part, and you've brought up it being questionable so do that fix, then do a quick check things out ,, again, these sorta things area never cut and dry.
     
  7. dougdowney

    dougdowney New Member

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    yeah i just ordered one for now. its hard for me to comprehend whats going on given the fact that ive already replaced everything. and since im getting a intermittent charge failure all i can guess now is that im losing connection somewhere. because according to my schematic... which is the most basic circuit ever theres nothing else in between thatll cause me problems other then wires. im not sure how exactly the starter relay will give me a voltage drop because i only have two isolated schematics on showing the start circuit and one showing the charge.. unless they carry a common somewhere
     
  8. RVFR

    RVFR Member

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    the trick here is how it routes the power and the leads going may not be all that great, I've also seen terminals get all messed up then there s electrical leakage which to me sorta sounds possible as it sounds like it does foul up it's good and warmed up. be interesting to know if it works ok when cold.
     
  9. dougdowney

    dougdowney New Member

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    i gave up on it for the night its getting cold this north eastern weather is wanting to be winter still so ill get back at it on friday probably and ill let you guys know what i figure out
     
  10. squirrelman

    squirrelman Member

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    ......" today and bam right back to having the no charge issue.. so im back to the drawing board again.. the only thing i have found so far that im going to be changing is my starter relay connection is pretty much toast."

    You're welcome, Bunky. :drinkers: That was post #2.:pig:
     
  11. Knight

    Knight New Member

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    To test for shorts: With the bike off put an ammeter between the negative battery terminal and the cable. Set it to the highest setting, 20 AMPS or such then lower the setting one at a time until you get a valid reading. 3mA or .003A is normal and the maximum. Higher numbers indicate a short. If so remove fuses one by one until the current drops. You have now identified the circuit with the short circuit. If this includes the starter relay you can replace it then redo the test. There is a short finder as well if you can borrow one from a mechanic.

    To check for a bad ground, put the multimeter in resistance mode between the battery negative terminal and various parts of the frame. It should read zero ohms or very close to zero. A high resistance means the grounds are not doing their job. Look at the terminal blocks that connect a dozen systems to one ground wire.

    With this problem running the bike may fry more components so hopefully you are not stuck as immobile without this vehicle.
     
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