Vulcan Verses
01-19-2006, 08:32 AM
Also See Getting at the R/R (http://www.vn750.com/forum/showthread.php?p=5495)
On the Yahoo VN750 site, go to “Files” (left hand side of the page), then “electrical and lighting,” and then “RR and Stator.”
Have your stator checked when the engine is very hot. I now know of two bikes that the stators failed to check out when hot, but tested ok cold. (one of them was mine) You should also be able to tell if you have a voltmeter on the bike. Check the system voltage after the bike's good and hot.
What are the symptoms of R/R failure?
Try this check list put together by Trent:
When the R/R fails (open or shorted diode(s)), the battery will not be charged properly as the bike is running. Eventually the bike will have no battery power... it WILL still run, but you have to keep it going since it will not restart (no current for the starter).
James had this issue and actually ran quite a while without a good battery. Not sure how he started the bike, may have pushed and dumped the clutch. Anyway, a bad R/R, if diodes short, can put excessive load on the battery and cause stator failure, which requires an engine pull. Do not panic, it is probably not that, and I do some testing first. Measure the battery voltage when the bike is running at about 3K RPM, should be around 14V if battery, stator, and RR are OK. If not, let me know and we can go from there.
Now since you said you can keep it running with the choke on, this indicates it very well may be fuel starvation. This is not a big deal. Check your float bowl levels. It takes 5 minutes and requires a clear vinyl tube attached to the bowl drains. If you need more info on how to do that, let me know. Does the bike backfire? If so, the fuel starvation could also be caused by an airleak on one of the carb boots. Could also be the plug wires or ignitor. Before going into all this, check the battery voltage first and advise. Starman.
Q: From what I've picked up in the postings from this group, it appears that the VN750's charging system has a few basic design flaws. Can someone confirm if what I understand is correct? It sounds like the stock voltage regulator (R/R???) overheats, tells the alternator to crank up the juice, which then causes failure of the stator. Since this sounds like something that a little preventative maintenance and field modifications would fix, I just want to make sure that I'm understanding the issue correctly. I've seen this happen on the various cars I've owned/fixed over the year's, but it appears it's a heck of a lot easier to replace most car's alternators that a VN750's stator.
A: You're correct Keith. Relocating the R/R (a bracket along the frame over the left passenger peg is the most chosen location)or removing the goat's belly will eliminate the heat source. The main preventive maintenance is installing a maintenance free battery. With the two combined you can rest a lot easier and enjoy more ride time *S*
A: I agree with Dianna. But I would add, you don't even want to think about replacing the stator unless you are forced to. It's a very tough job even for a veteran cycle mechanic. It is expensive, very time consuming, hard to do, and should be the last resort. And it's a job you can avoid if you heed everyone's advice. Do everything you can to keep the stator you have working. Lose the goats belly or move the R/R and get a sealed battery (WestCo), immediately, of not sooner. You will be very glad you did! If not, you will eventually wish you had! I bought my 1992 VN750 with a burned out stator (didn't realize it at the time) and eventually replaced it with an Electrex stator & R/R...myself. That's a job I do not want to tackle again. But, if you choose to do it yourself, there are a lot of really good people in this Yahoo group who can help walk you through it. They helped me a lot. Good luck.
Q: O.K. , heres the deal, I have replaced my fusebox, R/R, gone through 2 batteries, ( I now have a sealed WESTCO. ) ... Still battery will not stay charged during riding. I have a feeling that it is the stator. But, Here is the question. What is it exactly that the stator does? and what is the harm in me just keeping the battery on a BATTERY TENDER when I am not riding?
A: Harold...what symptoms indicate to you that the stator is NOT charging?? Here's a simple test I use... hook up a voltmeter to the two access leads under the right cover. Set to 'DC' voltage, and take the bike out for a spin. You should see the voltage vary from ~12.8 volts to ~14v depending on rpm. This variance is not linear...meaning that it will not read the same all time for all rpms, it depends on a few factors. The important thing is that you see voltages in the charging range of 13-14.5v consistently. You could do the above on the centerstand, also. Also, this is why a lot of us have volt meters installed on our bikes...I am constantly checking it out as I ride.
A: The first thing I suggest is checking your stator using the information on this page:
http://jr_allas.tripod.com/documents/running_poorly.htm
The purpose of the stator is the same as the alternator in your car. It supplies power to charge your battery and power all your lights and ignition system via the regulator/rectifier. When my stator failed the first time, the headlight began working intermittently because the stator could not supply enough voltage to energize the headlight relay, but there was enough voltage to power the ignition, although there was a decrease in my top-end speed because the motor would miss a lot and lose power.
If you never ride far from home, the choice is yours as to what you do, but there is no guarantee that the stator won't completely fail and leave you stranded when the battery completely loses charge, which doesn't take long. I must also note that the stock stator and regulator/rectifier combination can not supply enough power to charge the battery at idle. You need to get that puppy up to highway speeds for a while to do that. The Electrex stator and regulator/rectifier setup does supply about 13.5 volts at idle, so it would appear the battery can be charged, or at least maintained, while idling the motor.
As you'll see on this page: http://jr_allas.tripod.com/documents/Stator_RegRec_Replace.htm , it is a lot of work to replace the stator, but it can be done if you have patience, plenty metric tools, and a second pair of hands to help you pull and re-install the motor.
To do so, see this page: http://jr_allas.tripod.com/documents/gasket_replace.htm . I've had the motor out of my 1990 VN750 three times, so if you want to take on the task, I'll be glad to answer any questions. Good luck!!!
Check out Starmans link on my web page for fusing the stator. We (well he did most of it) did the work at his place. Go to www.carveyparker.com for his link.
If you remove the goats belly (GB), you remove the heat source to the R/R. With the GB removed the R/R will get more than enough cooling ventilation with the air flowing up through the empty frame where the GB was. There is really no need to move the R/R unless you just love your goats belly and want to keep it. Cost me $20 at the local muffler shop for them to make two pipes & clamps to replace the goats belly. The bike is lighter, runs better, cooler and sounds better. So my advice is, leave the R/R and lose the GB. JC
Regulator ground question I asked Electrex about this a couple years ago - there is NOTHING inside the r/r that is electrically connected to the case. The case is just a case (and heat sink). So, adding a ground wire does nothing (sorry Gypsy). Kenny in WV still lurking sometimes
Sure it does, it grounds the case. In any event ,Bulldog's relocation bracket is made of aluminum which will ground the case anyway. Freak
Electrically connecting the R/R case to battery negative doesn't affect the regulation. Mechanically connecting the R/R case to a thermally conductive media could affect the performance of the regulator.
On the Yahoo VN750 site, go to “Files” (left hand side of the page), then “electrical and lighting,” and then “RR and Stator.”
Have your stator checked when the engine is very hot. I now know of two bikes that the stators failed to check out when hot, but tested ok cold. (one of them was mine) You should also be able to tell if you have a voltmeter on the bike. Check the system voltage after the bike's good and hot.
What are the symptoms of R/R failure?
Try this check list put together by Trent:
When the R/R fails (open or shorted diode(s)), the battery will not be charged properly as the bike is running. Eventually the bike will have no battery power... it WILL still run, but you have to keep it going since it will not restart (no current for the starter).
James had this issue and actually ran quite a while without a good battery. Not sure how he started the bike, may have pushed and dumped the clutch. Anyway, a bad R/R, if diodes short, can put excessive load on the battery and cause stator failure, which requires an engine pull. Do not panic, it is probably not that, and I do some testing first. Measure the battery voltage when the bike is running at about 3K RPM, should be around 14V if battery, stator, and RR are OK. If not, let me know and we can go from there.
Now since you said you can keep it running with the choke on, this indicates it very well may be fuel starvation. This is not a big deal. Check your float bowl levels. It takes 5 minutes and requires a clear vinyl tube attached to the bowl drains. If you need more info on how to do that, let me know. Does the bike backfire? If so, the fuel starvation could also be caused by an airleak on one of the carb boots. Could also be the plug wires or ignitor. Before going into all this, check the battery voltage first and advise. Starman.
Q: From what I've picked up in the postings from this group, it appears that the VN750's charging system has a few basic design flaws. Can someone confirm if what I understand is correct? It sounds like the stock voltage regulator (R/R???) overheats, tells the alternator to crank up the juice, which then causes failure of the stator. Since this sounds like something that a little preventative maintenance and field modifications would fix, I just want to make sure that I'm understanding the issue correctly. I've seen this happen on the various cars I've owned/fixed over the year's, but it appears it's a heck of a lot easier to replace most car's alternators that a VN750's stator.
A: You're correct Keith. Relocating the R/R (a bracket along the frame over the left passenger peg is the most chosen location)or removing the goat's belly will eliminate the heat source. The main preventive maintenance is installing a maintenance free battery. With the two combined you can rest a lot easier and enjoy more ride time *S*
A: I agree with Dianna. But I would add, you don't even want to think about replacing the stator unless you are forced to. It's a very tough job even for a veteran cycle mechanic. It is expensive, very time consuming, hard to do, and should be the last resort. And it's a job you can avoid if you heed everyone's advice. Do everything you can to keep the stator you have working. Lose the goats belly or move the R/R and get a sealed battery (WestCo), immediately, of not sooner. You will be very glad you did! If not, you will eventually wish you had! I bought my 1992 VN750 with a burned out stator (didn't realize it at the time) and eventually replaced it with an Electrex stator & R/R...myself. That's a job I do not want to tackle again. But, if you choose to do it yourself, there are a lot of really good people in this Yahoo group who can help walk you through it. They helped me a lot. Good luck.
Q: O.K. , heres the deal, I have replaced my fusebox, R/R, gone through 2 batteries, ( I now have a sealed WESTCO. ) ... Still battery will not stay charged during riding. I have a feeling that it is the stator. But, Here is the question. What is it exactly that the stator does? and what is the harm in me just keeping the battery on a BATTERY TENDER when I am not riding?
A: Harold...what symptoms indicate to you that the stator is NOT charging?? Here's a simple test I use... hook up a voltmeter to the two access leads under the right cover. Set to 'DC' voltage, and take the bike out for a spin. You should see the voltage vary from ~12.8 volts to ~14v depending on rpm. This variance is not linear...meaning that it will not read the same all time for all rpms, it depends on a few factors. The important thing is that you see voltages in the charging range of 13-14.5v consistently. You could do the above on the centerstand, also. Also, this is why a lot of us have volt meters installed on our bikes...I am constantly checking it out as I ride.
A: The first thing I suggest is checking your stator using the information on this page:
http://jr_allas.tripod.com/documents/running_poorly.htm
The purpose of the stator is the same as the alternator in your car. It supplies power to charge your battery and power all your lights and ignition system via the regulator/rectifier. When my stator failed the first time, the headlight began working intermittently because the stator could not supply enough voltage to energize the headlight relay, but there was enough voltage to power the ignition, although there was a decrease in my top-end speed because the motor would miss a lot and lose power.
If you never ride far from home, the choice is yours as to what you do, but there is no guarantee that the stator won't completely fail and leave you stranded when the battery completely loses charge, which doesn't take long. I must also note that the stock stator and regulator/rectifier combination can not supply enough power to charge the battery at idle. You need to get that puppy up to highway speeds for a while to do that. The Electrex stator and regulator/rectifier setup does supply about 13.5 volts at idle, so it would appear the battery can be charged, or at least maintained, while idling the motor.
As you'll see on this page: http://jr_allas.tripod.com/documents/Stator_RegRec_Replace.htm , it is a lot of work to replace the stator, but it can be done if you have patience, plenty metric tools, and a second pair of hands to help you pull and re-install the motor.
To do so, see this page: http://jr_allas.tripod.com/documents/gasket_replace.htm . I've had the motor out of my 1990 VN750 three times, so if you want to take on the task, I'll be glad to answer any questions. Good luck!!!
Check out Starmans link on my web page for fusing the stator. We (well he did most of it) did the work at his place. Go to www.carveyparker.com for his link.
If you remove the goats belly (GB), you remove the heat source to the R/R. With the GB removed the R/R will get more than enough cooling ventilation with the air flowing up through the empty frame where the GB was. There is really no need to move the R/R unless you just love your goats belly and want to keep it. Cost me $20 at the local muffler shop for them to make two pipes & clamps to replace the goats belly. The bike is lighter, runs better, cooler and sounds better. So my advice is, leave the R/R and lose the GB. JC
Regulator ground question I asked Electrex about this a couple years ago - there is NOTHING inside the r/r that is electrically connected to the case. The case is just a case (and heat sink). So, adding a ground wire does nothing (sorry Gypsy). Kenny in WV still lurking sometimes
Sure it does, it grounds the case. In any event ,Bulldog's relocation bracket is made of aluminum which will ground the case anyway. Freak
Electrically connecting the R/R case to battery negative doesn't affect the regulation. Mechanically connecting the R/R case to a thermally conductive media could affect the performance of the regulator.