Help if u can

[HARDRIDE]

I HAVE AN 2002 MIDNIGHT VENTURE . ABOUT A WEEK AGO MY BATTERY WENT OUT SO I WENT AND BOUGHT A NEW ONE . PUT IT IN AND STATED IT UP AND TOOK THE NEGATIVE CABLE OFF AND THE ENGINE STOPPED, PUT THE NEGATIVE CABLE BACK ON AND IT STARTED UP AGAIN AND RAN UNTIL I TOOK THE NEGATIVE CABLE OFF AND IT WENT DEAD AGAIN . CAN'T SEE WHERE I HAVE A SHORT BUT THINK THERE IS ONE , HAVE LOOKED AT IT UP AND DOWN AND CAN'T SEE ANYTHING, I THOUGHT THAT THE GENERATOR WOULD KEEP THE BIKE RUNNING, BUT IT DOESN'T SEEM TO ;STUMPED CAN YOU HELP? I'VE ALSO CHECKED ALL THE FUSES AS WELL...

THANKS HARDRIDE:scared:

[LilBeaver]

Were you at idle when you took the cable back off?

 

On a bike (and most cars, unless you've got a utility vehicle with a high idle switch) when a vehicle runs at low rpms it actually taps the battery for some juice to keep everything going. The generator cannot keep up with the electrical demands all on its own unless the bike is running at a higher rpm...

 

In general, a generator functions by rotating a coil of wire inside a magnetic field. The rotating coil of wire is exposed to this time varying magnetic field which induces a current in the wire - thereby producing electricity which is then (on a vehicle) routed back through the rest of the vehicles electrical system. If the coil does not spin fast enough to keep supplying all of the electrical demands (that is the spark through the ignition system, lights, etc) then it draws from the battery; if the battery is no longer in the circuit - the system simply cannot continue to run.

 

In my opinion (as a Physicist and backyard mechanic) a better way to test the alternator is:

 

1) Start the bike, turn all electronics off (headlamps to low beams, etc)

2) Set a multimeter to the DC Voltage setting (minimum of 20V), connect the positive lead to the positive terminal on the battery and the negative lead to the negative terminal on the battery.

3) Rev the motor up to a high idle (2000 to 2500 rpm should be more than sufficient)

4) Read the measurement off of the Voltmeter.

5) Then turn on your high beams, hazards, and radio and read the voltmeter again

6) Turn off the bike, etc.

 

You should read at least 13.5V (more likely 14 or a little more) in both cases. In fact, after you turn everything back on, the reading should not have gone down very much... A little is expected but it should still be above 13V.

If you read 12V or less or there is a large drop with the additional draw it is very likely that there is a problem with your generator.

 

The generator must produce a slightly higher voltage than what the battery puts out since it must charge the battery (which can only be done if you overcome the terminal voltage of the battery with a significant enough potential difference so that the battery can be charged by the system).

 

I would NOT suggest revving up the motor then disconnecting the battery as this not only shocks the electrical system (since it is designed to deliver some of the electrical discharge, created by the generator, through the battery -- to charge/maintain it), but more importantly it is really quite inconclusive.

 

Hope that helps.

 

- Rick M.

Edited April 22, 2009 by LilBeaver

[wes0778]

:2cents:Don't know about these bikes, but the older '60s ones needed the battery connected to so the rectifier could regulate the voltage. Take my 68 DT-1. If you start it with out the battery connected, and turn on the lights, all the bulbs will pop like flash bulbs.

If that is the case, I can imagine what THAT would do to the electronics on a Venture.

[MAINEAC]

Dude you already posted this in Members introductions which really ain't the place for this question and then you go and repost it in the Royal Star Tech section when it should have been in the Second Generation Venture Tech Talk

section... you're 0 for 2... Just kidding ... Hey maybe you should post what city you're in/near in CA... It's a big state and maybe someone is nearby can give you hand troubleshooting your charging problem... It's worth a shot... BUT... I'm in CA right now and have been all over this state and I'm finding out that the majority of CA bikers aren't very friendly

Edited April 22, 2009 by MAINEAC

[wes0778]

Mark,

Kinda sorta hijacking this thread, but do you know if the Buckeye stator will fit a 1998 RSTC?

The website, says 99 and up, but some of the "stuff" in these V4s seems to be "all the same"

[MAINEAC]

I'm not sure... But RickH should be able to answer that question... Either shoot him a PM or an e-mail at http://www.buckeyeperformance.com/oem.htm...

[Squeeze]

You should NOT disconnect the Battery Pole while the Engine is running.

 

It probably won't harm anything else than the Reg,/Rectifier on Idle Speed, but when you rev it up, it sure will leave Skid Marks on the Electronics, such as CDI(Igniter Unit) und your Light Bulbs.

 

These 3 Phase AC Generator push out everything they have above Idle and when there no Voltage from the Battery to sensefor the Reg/Rect. it will stay closed and don't deliver any Voltage to the System, until the Diodes a shot, then it mostly likely WILL deliver anything what comes from the Generator, too much Voltage and not a DC Voltage.

 

The Battery NEEDS to be there and it should have some Voltage on it's own or the Charging System won't work as designed.

[Monty]

Squeeze is right. Even if you jump start a bike and let it run with a weak battery, the stator is working overtime just trying to charge up that bad battery. This can destroy a stator. This is why you are supposed to fully charge a battery before you use it.

 

If you unhook the battery while the engine is running, it puts a TREMENDOUS load on your charging system, and can destroy it.