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Discussion Starter #1
Having the stator replaced in my 05 with a mere 5200 miles on it. Could I be reasonably sure that a competent certified mechanic would know to check the regulator when the new stator gets installed? It could have caused the stator to go in the first place, right?

First bike, learning as I go.
 

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Right, the r/r could have killed your stator. You can check it yourself, after the stator is installed. You'll need a volt/ohm meter.

Get the mechanic to inspect it and see why it fizzled out on you. This is the first I've heard of such a new model frying its stator. When you get it replaced, ask for the old stator back. I'd like Hizzo to take a look at it. Oh, and make sure they replace it with a Kawasaki brand, not something else.
 

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yes, i am with cegodsey. do the check yourself. there is too much error in 'certified' motorcycle mechanics. And i would like to take a look at that stator. i am trying to figure out what is causing them to fail so soon. i know what caused mine to fail at 9k miles in my 04, but that is a single case. If you want, just pm me and we'll exchange info and i will send you s&h.

***Important*** i am more then willing to bet that you have a bad battery though, unless you sit in traffic alot. If you have a wet battery, change it with the stator that you are getting done with a sealed battery. Now if you do sit in traffic alot, you may wanna undertake a relocation for the R/R so that the heat doesnt cause it to fail again. Let us know how it turns out.
 

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Has there been a correlation between corroded connections and failed R/R's or stators? I thought I was seeing that trend.
 

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there is too many variables to rule just one issue as the cause. so far here is a list of what i have seen

1) hot climates and traffic
2) bad r/r (due to heat)
3) bad r/r connection
4) bad battery causes r/r to fry
5) the occasional flywheel rub on the stator causes short


these are all major potential issues that cause the failures. cant just say its always one or the other...
 

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Discussion Starter #6
Hizzo,
After talking to a friend who is a longtime Harley rider/mechanic...I'm leaning toward a faulty r/r having boiled the battery and fried the stator....I just bought a new battery the other day for the bike.
I'll get back to you on that stator


Edit....can you explain that #4 scenario to me?
 

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R.C.inOhio said:
Hizzo,
After talking to a friend who is a longtime Harley rider/mechanic...I'm leaning toward a faulty r/r having boiled the battery and fried the stator....I just bought a new battery the other day for the bike.
I'll get back to you on that stator


Edit....can you explain that #4 scenario to me?

Hizzo and cegodsey, see if I learned my lessons from this summer in order to answer the #4 scenario:

The battery is DC and all of the electrical components on the bike suck up the juice from the battery as the bike is running (or not - like if it's sitting in your garage and you forgot to turn the key to 'off' :BLAM: ). The only way to recharge the battery is to generate AC (stator), convert it to DC (rectifier), and then store it back in the battery. If the battery isn't holding its charge, the r/r is working that much harder to try to recharge the system; given where it's located on these bikes (under the battery box, where it can cook), the harder it works, the hotter it gets. And when the r/r gets fried, then "something unimaginable happens to the stator." Well, I think the current from the battery that normally would go through the r/r to the stator is now unregulated, and thereby theoretically sends an infinite amount of current to the stator (thereby blowing it).

That said, the regulator/rectifier set-up is both a "push" and "pull" system, right? It controls the flow of DC from the battery to the stator (push), but also converts the AC flow from the stator back to the battery.

Okay, now someone can correct my folk theory of how our 750 charging systems work (but that's what I took from my summer repair lessons). :notworthy
 

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That's really good and close. The difference is that the stator puts out to the rectifier/regulator, which in turn puts out to the battery. But how much each puts out depends on what it is putting out to. When the rectifier/regulator shorts, the output of the stator becomes infinite, which heats it up enough to cause it to short internally. (V/R=I, as R goes to 0, I goes to infinity).

The stator produces a lot of AC voltage and some current. The rectifier takes the voltage and converts it to DC. The regulator keeps the voltage less than 15 volts (thereabouts), which in turn charges the battery. In a perfect world, the regulator would be 100 % efficient, and all of the stator's output would be converted. But nothing's perfect, so the regulator's internal resistance converts some of the stator's output to heat.

As to #4, the first paragraph explains it, but here's a more generalized idea. Lets say you have a manual transmission car. You drive the car up to a wall and stomp down on the gas. What's it going to do? If it's a powerful car, it will push against the wall while spinning its tires. Now if you were to suddenly remove the wall, the car would go as fast as it could in whatever gear it was in, all the way up to and past the red line, until the engine blew up. That's a pretty good analogy. The wall is the internal resistance of the rectifier/regulator, the car is the current of the stator.

There is a scenario in which the regulator stops working and sends all the voltage that the stator can make through the rectifier and then to the battery. This is a good way to fry the battery.
 

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yep...
 

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Is this charging system typical of just the vn750 or all motorcycles? What can be done to upgrade it to something more efficient and less prone to failure? Comments
 

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danield said:
Is this charging system typical of just the vn750 or all motorcycles? What can be done to upgrade it to something more efficient and less prone to failure? Comments

I don't know about typical for all motorcycles, but you can relocate your rectifier/regulator so it isn't sitting on top of the hottest part of your bike (the goat's belly). There is other stuff too, the Vulcan Verses are tops for that kind of info.

But talking to the guys at the shop today, it was at one time a fairly common problem in the GoldWings. I didn't know that.
 

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The problem that makes it so much of a problem is that you have to pull the engine to change the darn thing. Like Kait said, relocating the r/r is good sense. If you look at other bikes, you'll see that the r/r is usually chrome plated and sitting in the wind somewhere. So yes, danield, this is a common problem among other motorcycles, but a PITA on ours. Oh, and the fact that they put the r/r under a wet cell battery is another boo boo.
 

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I'm shocked to hear your stator went with that few miles. I have a 2005 with 12,000 miles and have had no trouble. I wonder if your stator was bad the day it came out of the factory?
 

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1) This is a common issue throughout most motorcycles. Those motorcycles that are lucky to have an alternator like newer wings and some triumphs no longer have these problems as their poorly designed motorcycle alternator can be replaced with an automotive unit.
2) Stator failures that are in the 10-20k mile mark are linked to the insulation on the windings breaking down due to heat, which indicates cheap parts. I am currently working on a unit that hopes to fix this. I hope to have it installed by sunday. Most failures before the 10k mark seem to be related to any of the other causes. *** Dan also keep in mind you are way north, do ya'll ever experiance 100 degree days with low humidity?
 

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Hizzo3 said:
do ya'll ever experiance 100 degree days with low humidity?
Hey, I'm just 350 miles away, and we NEVER experience 100 degree days with low humidity. We DO experience 100 degree days with very high >90% humidity. Now Hizzo, you're not gonna make me believe that Dallas has low humidity...
 

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cegodsey said:
Hey, I'm just 350 miles away, and we NEVER experience 100 degree days with low humidity. We DO experience 100 degree days with very high >90% humidity. Now Hizzo, you're not gonna make me believe that Dallas has low humidity...

well we are in our third year drought... we vary from 20-60% normal not including rains. Humidity is important b/c that is where most your heat transfer occurs. just dry air does very little heat transfer, which should explain why bugs never did well in the desert.
 

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>>>>>Dan also keep in mind you are way north<<<<<<

I don't believe it has ever been 100 degrees in Seattle (that I know of) so maybe that is why we don't have many stator or R/R problems up here. We're lucky to have a few weeks when you don't need long-johns.
dan
 

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Dan said:
>>>>>Dan also keep in mind you are way north<<<<<<

I don't believe it has ever been 100 degrees in Seattle (that I know of) so maybe that is why we don't have many stator or R/R problems up here. We're lucky to have a few weeks when you don't need long-johns.
dan
I envey you. sometimes i wish i had some form of cooling gear that works the opposite of heated gear....
 

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With all the concern of the electrical system for the vn750, it appears that we should not be adding any additional lights, horns, etc that can cause more of a drain on the battery, stator, R/R, etc. However, I would like to add two additional driving lights. PIAA has some (super white 55-watt bulb that you mount on the bikes front fender. You can connect the wiring harness several ways 1. To ignition switch's positive wire so lights will operate only when the ignition is on. 2. To high-beam wire so lights will operate when high-beams are on. 3. Connect to low-beam positive wire so the lights will operate when low-beam is on. 4. Connect directly to the battery's positive terminal so lamps will operate ( accessory light switch) at any time. The pre-made wiring harness has an in-line fuse and relay built into it. With the new maintenance free battery installed, does anyone foresee a problem installing the lights.
 

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danield said:
With all the concern of the electrical system for the vn750, it appears that we should not be adding any additional lights, horns, etc that can cause more of a drain on the battery, stator, R/R, etc. However, I would like to add two additional driving lights. PIAA has some (super white 55-watt bulb that you mount on the bikes front fender. You can connect the wiring harness several ways 1. To ignition switch's positive wire so lights will operate only when the ignition is on. 2. To high-beam wire so lights will operate when high-beams are on. 3. Connect to low-beam positive wire so the lights will operate when low-beam is on. 4. Connect directly to the battery's positive terminal so lamps will operate ( accessory light switch) at any time. The pre-made wiring harness has an in-line fuse and relay built into it. With the new maintenance free battery installed, does anyone foresee a problem installing the lights.
Yes, I would not add lights ofer 20 whats each, and add a switch so they only turn on when on the highway and not in the city.
 
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