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Super Member
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Discussion Starter #1
Hey guys I'm back. A little sooner than I had hoped unfortunately.

So I recently installed A TPE stator from Tim Parrot, a mosfet r/r, and a mf agm battery. I checked the grounds and they seemed fine to me.

When the bike is cold it starts fine and runs fine. It puts out a little less than 14v at idle and goes up to 14.5 as I increase the rpms. After about 5-10 mins the voltage goes down to about 12.6v at idle and a little over 13v as I rev it.
It won't stall if I keep the revs up, but as soon as the rpms are down to idle it stalls out and the oil light goes on.

Does anyone know what the problem could be?

Thanks in advance for your help
 

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..have a vulcan good day!
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After about 5-10 mins the voltage goes down to about 12.6v at idle and a little over 13v as I rev it.
It won't stall if I keep the revs up, but as soon as the rpms are down to idle it stalls out and the oil light goes on.

Low on Oil.... Stator over heating.

maybe ? ? ?

WilliamTech
 

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Discussion Starter #3
The stator still puts out about 70v - 90v from the yellow wires when the engine is hot.
I thought that the oil light just goes on when the engine stalls out.

I'll check the oil level tomorrow


The oil light only lights up when the engine is about to stall and goes away if i roll on the throttle. But stays on if it has stalled
 

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Crap, I WAS in 5th gear.
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500 Posts
Oil light goes on when there is low oil pressure and the ignition switch is on. Low or no rpms equal low or no oil pressure. Your oil light is working fine. Sounds like maybe an r/r problem, is your old one functional?
 

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Discussion Starter #6 (Edited)
Just checked all grounds again and cleaned them just in case. also cleaned the connectors between the stator and the r/r.
checked the voltage again.
with the engine cold at idle i get around 14v and at 5k i get 14.5
when the engine warms up and the fan kicks in it's about 13v at idle and 13.3 at 5k, and when the fan goes off the voltage is back to normal.
later the voltage drops to <13v at idle and 13.3 at 5k even with the fan off.

the stator puts out 25-110 ac voltage when it's cold and when it's hot.

also something i noticed is that when the voltage goes down the engine wants to stall, but if i unplug the stator from the r/r the rpms go back up to normal idle.

and when the r/r is disconnected from the battery it is putting out 15.5v at idle and 15.3 at 5k


btw the oil is not low, but i do have a tiny leak.



any ideas?
 

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Discussion Starter #7
r/r is relocated and it's a mosfet so it shouldn't be overheating anyway

does it still sound like the r/r?
 

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Your voltage at idle seems really high. SHould be around 12.8 at 1100 rpms, jumping to 13.5 - 15.0 above 2500 rpms. The fact that its output is decreasing as the engine warms up sounds like that may be your culprit.
 

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What are the cold and warm idle rpm's. Warm idle should be 1100 rpms. Alot of people want it to sound like a Harley so they lower the rpm's way to low.
 

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If only it had 6th gear..
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I suspect the r/r is the trouble. Was it plug and play or did you have to modify your wiring. I've heard some aftermarket ones required some altering.
 

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Discussion Starter #12
Your voltage at idle seems really high. SHould be around 12.8 at 1100 rpms, jumping to 13.5 - 15.0 above 2500 rpms. The fact that its output is decreasing as the engine warms up sounds like that may be your culprit.
I thought it was normal for a mosfet r/r to produce around 14v at idle.

What are the cold and warm idle rpm's. Warm idle should be 1100 rpms. Alot of people want it to sound like a Harley so they lower the rpm's way to low.
the idle is at 1100

I suspect the r/r is the trouble. Was it plug and play or did you have to modify your wiring. I've heard some aftermarket ones required some altering.
It's the comple kit from roadstercycle.com it's plug and play and runs straight to the battery and to the stator bypassing the wiring harness
 

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Just curious, what did you do with the 3 non-stator wires that went to the original R/R? I went throught the same thing you did, stator from TPE and a mosfet from roadstercycle. The 3 non stator wires I cut at the plug protected the ends just taped them up in the harness, There no longer needed for anything.

Another question, where did you place the 30amp circuit breaker that came with the mosfet kit. I think how those things work if they heat up they will trip and reset themselves when they cool down. Something you can google to see how they work.

Wondering if this would help at all, with the engine cold. Check your Stator continuity between the wires and to ground, then with the engine hot after you are experiancing the problem shut the engine off and do the checks again.

The engine loosing RPMs when the voltage drops dont make sense to me unless the battery voltage is low. With a good battery you should be able to unplug the R/R and the engine will still run untill battery voltage cannot support the ignition.
 

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Have you checked the stator leads to engine case hot and cold? It's possible that the insulation is marginal when cold, then bad when it warms up. Need to check each yellow lead to engine case both hot and cold. Should read infinite or open in all cases.

Jon
 

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I think it is that MOSFET R/R.
 

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I think it is that MOSFET R/R.
Why would you think that? You have already said you don't know how they work,and that you don't like them ,That's OK but to trouble shoot something you need to know how it works,Just saying.

The post about checking for a grounded stator. at cold and hot temps,seems to be the most logical place to start,since it seems to be temp related,
 

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Why would you think that? You have already said you don't know how they work,and that you don't like them ,That's OK but to trouble shoot something you need to know how it works,Just saying.

The post about checking for a grounded stator. at cold and hot temps,seems to be the most logical place to start,since it seems to be temp related,
I know how a transistor works. I am an amateur radio operator N7MUB. Many amateurs do not like MOSFETs, because they are not amateur friendly. Amateurs tend to like to work on their own stuff. I work on a lot of electronics on vehicles that I do not completely understand. I am not an electrical engineer. I was trained how to use the diagnostic equipment and software to hunt down and fix problems with modern automotive electronics. Even the instructor did not know how they actually worked. Nobody I know has any idea how a microprocessor works. But I have had bad experiences with MOSFET devices used on vehicles, they seem to be very fragile. And I would have no idea how to rest a motorcycle R/R.

The stator is a very straightforward old fashioned electrical device. It is easy enough to test. About the only 2 parts in the charging system are the stator and R/R.
 

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I know how a transistor works. I am an amateur radio operator N7MUB. Many amateurs do not like MOSFETs, because they are not amateur friendly. Amateurs tend to like to work on their own stuff. I work on a lot of electronics on vehicles that I do not completely understand. I am not an electrical engineer. I was trained how to use the diagnostic equipment and software to hunt down and fix problems with modern automotive electronics. Even the instructor did not know how they actually worked. Nobody I know has any idea how a microprocessor works. But I have had bad experiences with MOSFET devices used on vehicles, they seem to be very fragile. And I would have no idea how to rest a motorcycle R/R.

The stator is a very straightforward old fashioned electrical device. It is easy enough to test. About the only 2 parts in the charging system are the stator and R/R.
Do you even know what MOSFET means Jerry, it is a transistor, Metal Oxide
Semi-conductor Field Effect Transistor ,If you understand a transistor you should understand it.As far as being fragile ,I beg to differ,the best thing that ever happened to electric fork trucks were mosfet drive controllers ,nowhere near the number of parts as the old resistor trucks,or even the SCR trucks and very durable,the only trouble they ever gave me is that they almost starved me to death NOT tearing up,The old systems were hard to trouble shoot and tore up frequently,therefore I made a lot of service calls on them,not so on the new ones.The original R/R is solid state as is the Mosfet and non serviceable and the old style generated a lot more heat which is the enemy of efficiency in an electrical system.

I only have High school education and technical training no engineer here either.But at least my instructors new their job and could make it understandable.May be that is what frustrates you so much,if I had to work on stuff every day I did't understand I would't like any thing new either ;)
 

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Yes, I know what MOSFET is an acronym for. I do not really understand the oem R/R on motorcycles. A motorcycles charging system is completely different from a car. The alternator output on a car is load controlled, the more load you place on it, the more current it puts out. If there is no load on it, it just sits there and spins. On a motorcycle however, the stator has no output control. It runs at full capacity at all times, when the engine rpm is high enough. Even on bikes with low output stators like the Vulcan 750, the bike does not use all the current the stator produces, so it must be disposed of somehow. It is disposed of by being shorted directly to ground by the R/R. The resistance caused by doing that is what makes the R/R get hot. It basically serves as a resistance heating element, turning unused current into heat. That is why it has fins on it.


I have never ever had problems with one of these things until I got my '85 Goldwing. It works the same way, only it's stator puts out 500 watts, which is about 35 amps at 12V. It's tiny little R/R, about the same size as the one on the VN750 lacks the capacity to handle the kind of power that it must dispose of, causing the R/R to run red hot. Mine actually started a fire by burning the plastic insulation on the wires that were touching it.

I belong to 5 GW forums, and there are a couple of electrical engineers on most of them. They were unable to come up with any way to deal with the problem, other than abandoning the stock charging system altogether, and installing an automotive alternator, driven by a belt off a pulley on the front end of the crankshaft, which is what I finally wound up doing. I made my own mounting bracket, and used the recommended alternator, one designed for the last few years of the former Chevy/Geo Metro. It puts out 55 amps, but only if you put a load on it that will draw that many amps. It has a simple one wire hookup. It does not overheat. MANY 4 cylinder Goldwing owners have gone to this setup, and I have yet to hear one complaint. This is what Honda, and all motorcycle manufacturers should have done in the first place. I never understood the need to generate more current than you need, only to short it to ground. It's a cheap cheesy system that was first used on motorcycles back when they first started installing charging systems on them. It became outdated decades ago, just like tube type tires, but manufacturers still use them. The 1500/6 Goldwing was the first motorcycle to have a real load controlled charging system, and it and the 1800 are probably still the only motorcycles ever made that have them.


The instructor was not an electrical engineer either. He made no secret of the fact that he did not know HOW most of this stuff worked, other than the basics, like what it did, and how to figure out if it was doing what it was supposed to or not. You do not need an engineering degree to work on this stuff, that is what the diagnostic equipment and the vehicle specific software is for. All you need to know is the proper procedures to follow. That is what the class was for. In other words, it takes a computer to figure out what is wrong with another computer. You just have to know how to operate the diagnostic computer, and follow the step by step procedures. This stuff is very specific to the vehicle being worked on, the software comes from the vehicle manufacturer, and you have to enter the vehicles VIN in order for the diagnostic computer to identify it. It's actually very boring, I'd rather do oil changes all day.
 
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