Cooter Posted January 16, 2007 Share Posted January 16, 2007 I'm checking out the charging system on my '98 VFR in anticipation of taking a two week trip this spring. All of the connections between the stator and the RR look good as well as the connections from the RR to the battery and no signs of overheating in any of the wiring. In testing the system it has a static voltage of 12.6 volts and an idling voltage of around 13.8 but drops to around 13.2 - 13.1 at 5K rpm with the brights on. I also checked the stator windings for both resistance and shorts to ground and all was Ok but the stator voltage would never go above 38 - 39 volts when measuring between legs, all legs read the same. I'm not currently having any problems with the bike but want to circumvent any looming issues before I hit the road. I've read several posts saying that the voltage drop from idle to 5k is normal, others and the manual say I should be getting in excess of 14v at 5k but everything I've read says I should be getting in excess of 50v from the stator. I did the test with the bike warmed up to 175 degrees but not after a ride if that has any effect. What are the thoughts about this from those of you who have been through the eletrical issues. I'm the second owner of this bike with 23,000 miles on it and don't know if it's had any problems in the past or if the RR has been changed out. I always store the bike with a battery tender. Thanks for any help or opinions. Link to comment Share on other sites More sharing options...
Member Contributer chris2992 Posted January 16, 2007 Member Contributer Share Posted January 16, 2007 Exact same problems I'm having. Same mileage and everything. I have a volt and amp meter on board with me, when riding, as the RPM's rise, voltage goes down, mine has gotten to the point of droping to below 12.5v. I have replaced the battery, RR and cleaned up the wiring connections, still have the problem. That only leaves the stator. I have spoken with Ricks Electronics and they will re wind your stator for a higher amperage than stock as well as a 1 year warranty for $20 cheeper than the honda part. Check this link to a thread I started Link to comment Share on other sites More sharing options...
wera803 Posted January 16, 2007 Share Posted January 16, 2007 Exact same problems I'm having. Same mileage and everything. I have a volt and amp meter on board with me, when riding, as the RPM's rise, voltage goes down, mine has gotten to the point of droping to below 12.5v. I have replaced the battery, RR and cleaned up the wiring connections, still have the problem. That only leaves the stator. I have spoken with Ricks Electronics and they will re wind your stator for a higher amperage than stock as well as a 1 year warranty for $20 cheeper than the honda part.Check this link to a thread I started Higher amperage than stock?? How much higher?? Link to comment Share on other sites More sharing options...
Member Contributer chris2992 Posted January 16, 2007 Member Contributer Share Posted January 16, 2007 IIRC, stock was 50 amp, and they could squeeze 55 amp out of it. Not too much, but worth noting. The thing that sells it to me is the 1 yr warranty. Link to comment Share on other sites More sharing options...
Guest Posted January 16, 2007 Share Posted January 16, 2007 Stator output voltage is definitly low. It should be 55-60 Volts AC @ 5000 RPMs I'd pull the cover and check for any overheated coils...............they'll be a nice toasty brown. Personally, I'd stick with the OEM stator. My experience with rewinds is poor. Link to comment Share on other sites More sharing options...
Cooter Posted January 16, 2007 Author Share Posted January 16, 2007 chris2992 - have you checked your stator output voltage, curious to hear if yours is low as well. Does Rick's rewind your stator or do a core exchange arrangement, if they rewind yours, do you happen to know how long it takes? Anyone have any idea why a stator would put out less voltage and not show a abnormal resistance or shorting to ground? Link to comment Share on other sites More sharing options...
Member Contributer chris2992 Posted January 17, 2007 Member Contributer Share Posted January 17, 2007 No I haven't checked my output voltage, havent had time. Will do that before I pull the stator out. You send your existing stator to Rick, they rewind it and send it back. You pay shipping to them, they ship it back to your. They said it takes around 5 business days once they recieve yours + shipping time = total time. Link to comment Share on other sites More sharing options...
Member Contributer VFR FLYER Posted January 17, 2007 Member Contributer Share Posted January 17, 2007 IIRC, stock was 50 amp, and they could squeeze 55 amp out of it. Not too much, but worth noting. The thing that sells it to me is the 1 yr warranty. ponder this before increasing amperage..........the amps you make have to be consumed by either use (lights, heated everything) or charge the battery or be dissappated as heat at thr R/R. isn't a flaming R/R one of our main problems? Link to comment Share on other sites More sharing options...
Guest Posted January 17, 2007 Share Posted January 17, 2007 This is a good thread, i have seen the same(voltage dropping) when revving up on 2 different bikes ('98,'00, but this has been going on for years on my '98. I have a headlight modulator that flashes slowly when at idle, then speeds up when revving up. Actually this is how i check my charging system when riding around, when i get behind a car at a red light, i rev the engine and watch the flashing increase. Not the most scientific way, but it works. If my charging system isn't working the flashing wouldn't increase. Maybe some of the 5th gens can take some readings from their battery and stator and post them. Possibly this stator voltage is around normal and there isn't really a problem. My stator is reading low too, but has been for some time. I hate worrying about something that i shouldn't be. The R/R is another thing though. Link to comment Share on other sites More sharing options...
Cooter Posted January 17, 2007 Author Share Posted January 17, 2007 khyron - I'm with you on this. I've never had a problem with this bike in the two years that I've owned it and too, don't want to to worry about something that's not a problem. The charging system has always kept keep the battery up no problem. I've done a few 12 hr rides so it's not that the battery is always fresh from the Tender. Many others report that their voltage drops on rising engine speed to the low 13v range and never get out of the high 13v range at idle. I'm pretty sure that everyone that reported this was on 5th gen. models but I'm not positve about that. Maybe this is a good thing in that it strains the R/R less by having to disipate less heat. Given the history of this topic, it's hard to be totally complacent about this in anticipation of setting out on a trip half way across the country. I keep hoping that someone with real knowledge of motorcycle charging systems speaks up here. I've also sent an e-mail to Rick's with the voltage numbers to see if they respond one way or another. I'll pass along any response that I get. Thanks to all who have voiced an opinion so far. Link to comment Share on other sites More sharing options...
Misspent Youth Posted January 17, 2007 Share Posted January 17, 2007 I've posted more detail elsewhere on this board, but I had the same "problem" (dropping voltage on rising rpm and sub-14v charging at all times) and concluded it was due to failing r/r so I replaced it (battery was almost brand new) with the upgraded Honda part and got back some voltage, but still low. I researched the issue here/elsewhere, and on the Aprilia site (Futura's have undersized wires in charging system and that voltage drop is supposedly a symptom of too much resistance in the wiring - bigger wires fix it) and direct-wired the r/r hot/ground to the battery using thicker wires. Got back a 1/2 volt, so then I was up to 13.98 volts. I was still looking for >14v, so I measured the vac at the stator (which checked out otherwise) and found 59v, but was concerned it still had problems so I replaced it with a new Honda stator and peak voltage actually went DOWN to 13.91-94. Looks like that's the best I'm going to do. It charges up, it holds the charge, it starts, and nothing suggests the charging system's got any "issues," so that's where I'm leaving it. I agree with others here who have said that as long at it's putting out in excess of 13.5v or so, you're in good shape, but if drops below that, you need a new r/r, if not also a new battery (batteries get trashed by weak r/rs). By contrast, my new-to-me '92 w/new battery pumps out a steady 14.4-6v without blinking an eye. I've read here that using the 6th gen r/r with a minor adapter change (when fitting to a 5th gen) enables use of a "sensing" wire that goes to the battery and allows higher peak voltage because the r/r will then allow more juice into the battery, rather than dump it to the atmosphere via the r/r. Others probably have more info. Link to comment Share on other sites More sharing options...
Cooter Posted January 17, 2007 Author Share Posted January 17, 2007 IIRC, stock was 50 amp, and they could squeeze 55 amp out of it. Not too much, but worth noting. The thing that sells it to me is the 1 yr warranty. ponder this before increasing amperage..........the amps you make have to be consumed by either use (lights, heated everything) or charge the battery or be dissappated as heat at thr R/R. isn't a flaming R/R one of our main problems? Amperage is a measure of how much current is available to a load limited by either the source of the current or the circuit from the source to the load. In the case of the stator being able to put out an additional 5 amps only means that it's capable of producing the additional current if needed without it'self failing. The question is will the rest of the circuit wiring and R/R be capable of carrying the additional current should you add the additional load through accessories or fault. In a 12 volt system, this would amount to an additional 60 watts that the alternator could provide if the rest of the circuit can carry it. What it does provide is additional headroom at the stator if it's at or close to it's maximum capacity (this is key) making it less prone to stress failure. It woud also allow you to power more accessories as long as the additional current was accomodated in the wiring, However there is a bottle neck at the r/r that can't be wired around so if the r/r is unable to handle the additional load it will fail. The point being that the stator being able to provide the additional current will not put the additional current into the system unless it's called to. Link to comment Share on other sites More sharing options...
Cooter Posted January 17, 2007 Author Share Posted January 17, 2007 I've posted more detail elsewhere on this board, but I had the same "problem" (dropping voltage on rising rpm and sub-14v charging at all times) and concluded it was due to failing r/r so I replaced it (battery was almost brand new) with the upgraded Honda part and got back some voltage, but still low. I researched the issue here/elsewhere, and on the Aprilia site (Futura's have undersized wires in charging system and that voltage drop is supposedly a symptom of too much resistance in the wiring - bigger wires fix it) and direct-wired the r/r hot/ground to the battery using thicker wires. Got back a 1/2 volt, so then I was up to 13.98 volts. I was still looking for >14v, so I measured the vac at the stator (which checked out otherwise) and found 59v, but was concerned it still had problems so I replaced it with a new Honda stator and peak voltage actually went DOWN to 13.91-94. Looks like that's the best I'm going to do. It charges up, it holds the charge, it starts, and nothing suggests the charging system's got any "issues," so that's where I'm leaving it. I agree with others here who have said that as long at it's putting out in excess of 13.5v or so, you're in good shape, but if drops below that, you need a new r/r, if not also a new battery (batteries get trashed by weak r/rs).By contrast, my new-to-me '92 w/new battery pumps out a steady 14.4-6v without blinking an eye. I've read here that using the 6th gen r/r with a minor adapter change (when fitting to a 5th gen) enables use of a "sensing" wire that goes to the battery and allows higher peak voltage because the r/r will then allow more juice into the battery, rather than dump it to the atmosphere via the r/r. Others probably have more info. MY - You didn't state whether your 13.91-94 volts were at idle or at higher RPM and if it still dropped at higher RPM with the new stator and wiring changes, I'd be curious to know. My main issue is whether my lower than normal Stator output voltage is a concern or not given that it seems to be charging fine. My service manual doesn't even describe the voltage output test, only the resistance and continuity to ground tests for the stator. I've gotten the numbers from here and from the Electrosport site. Ive also seen the posts regarding the 6th gen rr thanks for the reference. Link to comment Share on other sites More sharing options...
Misspent Youth Posted January 18, 2007 Share Posted January 18, 2007 quote]MY - You didn't state whether your 13.91-94 volts were at idle or at higher RPM and if it still dropped at higher RPM with the new stator and wiring changes, I'd be curious to know. My main issue is whether my lower than normal Stator output voltage is a concern or not given that it seems to be charging fine. My service manual doesn't even describe the voltage output test, only the resistance and continuity to ground tests for the stator. I've gotten the numbers from here and from the Electrosport site. Ive also seen the posts regarding the 6th gen rr thanks for the reference. Sorry about that - all numbers were at 5k. My '98 - idles at 12.8 or so, then lifts to 14.2-4 or so at 2k, then progressively drops off as rpm rises until it stabilizes at the 13.91-94v number. I had heard/read that the voltage drop on rpm rise was due to too much resistance in the too small wiring, causing the juice to "back up" into the r/r, if you will. I also heard/read that the drop off as rpm rises was due to corroded or otherwise bad grounds. Before I did my rewire, I cleaned all contacts, including ground on frame and the one on brake thing that's attached to the back of the motor, under the seat, where the battery ground goes to the rest of the system. Because some had said the aluminum frame made for a bad ground, I tied the frame ground wires directly to the battery ground - all with the same results noted above. I then did the rewire and noted the improvements stated, after which I replaced the stator. The only thing I haven't done is to try the 6th gen r/r with the sensing wire. For now, things are charging fine so I won't worry about it. My suggestion would be to use an attached voltmeter (to the battery) and if you've got 13.5v or better at 5k, and your battery will hold 12.8v or better for 24 hours (after a full charge), then don't worry about it. If the battery won't hold the indicated figure, I'd replace the battery. If the system won't put out 13.5v, I'd replace the r/r. Assuming you've accurately assessed your stator's vac output, I'd probably install a new stator before a long trip. Link to comment Share on other sites More sharing options...
Cooter Posted January 18, 2007 Author Share Posted January 18, 2007 quote]MY - You didn't state whether your 13.91-94 volts were at idle or at higher RPM and if it still dropped at higher RPM with the new stator and wiring changes, I'd be curious to know. My main issue is whether my lower than normal Stator output voltage is a concern or not given that it seems to be charging fine. My service manual doesn't even describe the voltage output test, only the resistance and continuity to ground tests for the stator. I've gotten the numbers from here and from the Electrosport site. Ive also seen the posts regarding the 6th gen rr thanks for the reference. Sorry about that - all numbers were at 5k. My '98 - idles at 12.8 or so, then lifts to 14.2-4 or so at 2k, then progressively drops off as rpm rises until it stabilizes at the 13.91-94v number. I had heard/read that the voltage drop on rpm rise was due to too much resistance in the too small wiring, causing the juice to "back up" into the r/r, if you will. I also heard/read that the drop off as rpm rises was due to corroded or otherwise bad grounds. Before I did my rewire, I cleaned all contacts, including ground on frame and the one on brake thing that's attached to the back of the motor, under the seat, where the battery ground goes to the rest of the system. Because some had said the aluminum frame made for a bad ground, I tied the frame ground wires directly to the battery ground - all with the same results noted above. I then did the rewire and noted the improvements stated, after which I replaced the stator. The only thing I haven't done is to try the 6th gen r/r with the sensing wire. For now, things are charging fine so I won't worry about it. My suggestion would be to use an attached voltmeter (to the battery) and if you've got 13.5v or better at 5k, and your battery will hold 12.8v or better for 24 hours (after a full charge), then don't worry about it. If the battery won't hold the indicated figure, I'd replace the battery. If the system won't put out 13.5v, I'd replace the r/r. Assuming you've accurately assessed your stator's vac output, I'd probably install a new stator before a long trip. I'm kind of getting to that point, just replace it all, it's not that much money and see what happens, if the thing tests out better then so much the better and if it doesn't, I know it's all new and I have spares. Seems like a dopey way to maintain a motorcycle though! Link to comment Share on other sites More sharing options...
Misspent Youth Posted January 18, 2007 Share Posted January 18, 2007 I'm kind of getting to that point, just replace it all, it's not that much money and see what happens, if the thing tests out better then so much the better and if it doesn't, I know it's all new and I have spares. Seems like a dopey way to maintain a motorcycle though! I don't disagree. The charging system and cooling systems appear to be the weak points on this bike. BTW, my theory on the thermostats sticking open and running the bike too cool is that the silica-free coolant doesn't have sufficient abrasive to remove corrosion that accumulates as the coolant degrades over time. The corrosion then reaches the point of holding the thermostat open (not sure why it doesn't fail closed). Link to comment Share on other sites More sharing options...
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