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rider
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213 Posts
Discussion Starter #1
i'm (yet again) in the midst of some charging system difficulties.

i've tested the resistance of the three stator leads and i'm getting appropriate readings (.3 - .5 ohms).

i've tested each of the three stator leads to ground and there is no continuity.

here's the issue:

if i measure volts ac between the three stator leads, all three pairs of readings are giving me only about 30 vac at 5000 rpm.

given the first two tests passed, could this low voltage still mean a bad stator? previous tests (months ago, with the same stator) always showed between 70-80 vac across the leads.

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additional details for those interested: i have a voltmeter hooked up to the accessory leads and volts at idle are around 11.2, but will climb up to the mid 13's (and even sometimes into the 14's) after running for a while on the road at around 5k rpm's.
 

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Simple Solutions
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965 Posts
i'm (yet again) in the midst of some charging system difficulties.

i've tested the resistance of the three stator leads and i'm getting appropriate readings (.3 - .5 ohms).

i've tested each of the three stator leads to ground and there is no continuity.

here's the issue:

if i measure volts ac between the three stator leads, all three pairs of readings are giving me only about 30 vac at 5000 rpm.

given the first two tests passed, could this low voltage still mean a bad stator? previous tests (months ago, with the same stator) always showed between 70-80 vac across the leads.

------

additional details for those interested: i have a voltmeter hooked up to the accessory leads and volts at idle are around 11.2, but will climb up to the mid 13's (and even sometimes into the 14's) after running for a while on the road at around 5k rpm's.
those test show me a working stator how is your R/ R? double check ground connections ...
what kinda battery do u have how old and is it a agm???
 

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rider
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213 Posts
Discussion Starter #3
those test show me a working stator how is your R/ R? double check ground connections ...
what kinda battery do u have how old and is it a agm???
thanks for the response, cbr.

the r/r is less than a year old and i just bought a new maintenance free battery a few weeks ago (thinking that was the problem).

shouldn't the vac coming off the stator leads be much higher?
 

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rider
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213 Posts
Discussion Starter #4
here's the thing i keep coming back to...

that electrosport fault finding pdf states that if the volts ac coming off of the stator leads is less that 50 volts ac, the stator is bad. i just checked again, and i'm getting a maximum of 40 volts ac at around 5500 rpm. this is with the engine relatively cold... meaning the oil hasn't heated up enough to degrade the power coming off of the stator. i've checked this before (every few months as i'm paranoid about the electrical system) and this value has always been in the 60-80 volts ac range.

weird thing is... i just charged the battery on a battery tender, and with everything hooked up, i'm getting around 14.5 v at the battery around 5000 rpm. so all seems good, right? at idle though... around 1000 rpm, i'm only seeing 11.5 v. this doesn't seem right... the voltage should be hovering in the low 12's.

if you're interested, this is another thread i had going back in september... still trying to get this solved: http://www.vn750.com/forum/showthread.php?t=12720 from back in september when the bike wouldn't start.

i'm in the process of cleaning all the connectors, so i'll check back in in a bit.
 

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rider
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213 Posts
Discussion Starter #5
well, same thing. at 1000 rpm i'm sitting at 11.5v. at 5000 rpm i'm up in the high 14's. not sure why that's dropping to 11.5v in the low range, but everything seems fine in the upper range. even so... if you check out that other thread... [http://www.vn750.com/forum/showthread.php?t=12720]... i was getting the same types of readings (high 14's for volts) and still the electrical system would die.

i've thoroughly cleaned the ground connection and cleaned the terminal near the starter. the battery is only a few weeks old and is a mf type.

wonder what else could be going on...
 

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Calif Rider
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725 Posts
If you are really checking the volts at 1000 RPM that is low. The bike should idle at 12 or 13 hundred RPM. The extra RPM may give you the jump in volts that you need.. You are right you should get more volts at idle when bike is still warming up. I usually get mid 13's or low 14's at idle on warm up. Once warmed up and sitting at a light the volts will be high 12's or low 13's, that is untill fan is on and lowers volts will register on the guage.
 

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rider
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213 Posts
Discussion Starter #7
just went on a ride up to the local radio shack to get some new bullet connectors for the wires attached to the stator leads.

after 8 miles of riding, voltage is hovering around 13 at 5000 rpm and sitting at lights the voltage is dropping to low 11's.

installed the new bullet connectors... no impact either way.
 

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Simple Solutions
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965 Posts
just went on a ride up to the local radio shack to get some new bullet connectors for the wires attached to the stator leads.

after 8 miles of riding, voltage is hovering around 13 at 5000 rpm and sitting at lights the voltage is dropping to low 11's.

installed the new bullet connectors... no impact either way.
i would goto an electrical suplyer for those bullet connectors... or just soldier and shrink wrap ...
 

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The Professor
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3,147 Posts
well, same thing. at 1000 rpm i'm sitting at 11.5v. at 5000 rpm i'm up in the high 14's. not sure why that's dropping to 11.5v in the low range, but everything seems fine in the upper range. even so... if you check out that other thread... [http://www.vn750.com/forum/showthread.php?t=12720]... i was getting the same types of readings (high 14's for volts) and still the electrical system would die.

i've thoroughly cleaned the ground connection and cleaned the terminal near the starter. the battery is only a few weeks old and is a mf type.

wonder what else could be going on...
When you hook th VM into the acc leads you loose .5 -.7v compared to the battery directly, So your 11.5v is actualy 12.0v+. It's normal for the volts to drop when at idle, idle should be 1100 rpm when engine is warm.

Are you having the same problem with the batery dying or a different problem?
 

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rider
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213 Posts
Discussion Starter #10
thanks for the responses, guys.

cbr: yeah, i probably should have gotten more industrial fittings, but the fittings i bought are virtually identical to the existing ones.

lance: i've had that voltmeter wired up to the accessory leads for a while... you'd be surprised, i've measured at the battery and there's really not too much of a difference between the two. maybe .1-.2v or so. historically i've been in the low to mid 12's at 1000 rpm.

yep, same problem... battery is dying. after i ride the bike for a while the voltmeter reads in the low 13's around 5000 rpm.

i think i might try a new stator. i keep coming back to the fact that it's only putting out 30-40 volts ac at 5000 rpm. in the fault finding doc, this is one of the tests and if the stator isn't putting out 50+ volts ac, the doc says it's bad. this is definitely something that has changed... i've typically gotten 60-80 volts ac during these tests before.

i'm on my second stator and fortunately i bought and installed the toc modded cover the last time i changed it, so it shouldn't be too difficult.
 

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The Professor
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3,147 Posts
What stator and R/R do you have installed now? :beerchug:
 
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