Cooter

I said I would report back after I installed the new parts. Just to remind everyone, I was not having problems with the bike staying charged, just lower than spec charging voltage that would drop even lower, into the low 13's, as the rpms rose and was only showing 38 volts output max from the alternator. I also had the original RR. I had no signs of over heated wiring or connectors. I decided that I would go ahead and replace the stator and regulator proactively. My stator looked very similar to Chris' very toastie on the same side as his pictures show but it still tested OK except for low voltage output. After replacing the stator and RR, I am now getting charging voltages in the high 13' to low 14's with little to no drop on rising RPM and output from the stator of 50 volts and up, rising with rpm. I did do a little maintenance on connections but nothing that I would consider an A HA. I now firmly believe that much of the problem with these bikes starts with a failing stator. As the stator begins to fail under heat and load, it appears that the voltage drops and the current rises which then starts playing havoc with the rest of the charging system. I have posted references to this in my previous posts on this topic as well as a post on the general fraility of this type of alternator (stator) design. For those of you having multiple rr failures, I would consider replacing the stator. For the record, my bike is a 98 model with 24,000 miles and no history of electrical problems and hopefully, none in the near future.

I've ordered a new stator and RR (OEM from Honda) and am going to wire it all directly to the battery using Weather Pack disconects and No. 10 sxl wire with a dedicated 40 amp fuse holder, I'll dialectric grease all connections and use thermal paste in mounting the regulator. If I end up with the same voltages then I'm going to call it done and carry the old rr under my seat as a back up. I'll report the results when I'm done.

I too, haven't heard great things about Electrex and wasn't suggesting their products. After reading your post and having my own issues, I really started digging around to try to learn how exactly the various components of the charging sytem worked. There is a fair amount of information out there (I was searching motorcycle voltage regulator design). The article I quoted was the first explanation that made sense as to why a stator would test OK in one circumstance and not another or in my case why the stator shows low output but continues to function in the system (it is failing slowly). I ran across another tech article from an old bike magazine that said that this type of charging systen design is so flawed (the 2 piece design of a stator mounted off the end of the crank relying on oil for cooling and a seperate rr) that it really can't be expected to last much more than 20,000 mi. It is still in wide use on sportbikes because of it's cheap to produce, light weight and compact. Here's the link www.reptilesmagazine.com/mcn/technical/MCNdec05charging.pdf Don't ask me why it's in a Reptilesmagazine link, the page says it's from Motorcycle Consumer News, ah the mysteries of the internet! Please post your outcome with a Rick's rewind.

I started the other thread on 5th gen charging problems a couple of days ago so I'm interested in your results. At first, from your description I would have thought that you had a second bad rr given that your voltage from the stator seems good until it's attached to a load but I found this snippet of information on a BMW site. It originally came from the Electrex site but doesn't seem to be there any longer and coincidentally, refers to VFRs! Anyway, after reading it, I think you should replace your stator and unfortunately, possibly your your rr as well as it appears that a failing stator will take out the regulator. Here's the quote. <<VRF Regulator Rectifier Basics Inside there is a six diode full wave rectifier, and every phase input can be switched to ground through a thyristor. The thyristors are switched by a regulator circuit that measures the DC output voltage. We call this a shunting regulator. It is a very simple system, and doesn't work very efficiently. But it does the job while not dissipating too much heat. That is why most OEM manufacturers still use this setup. First of all the regulator relies on it's heatsink. That in itself is not bad , as long as there is good thermal contact between the diodes and thyristors inside the unit to the housing, and as long as there is a good airflow. Quite often when a regulator/rectifier fails, a new one will fail after a fairly short time. It is a recurring problem (not on all bikes, but has been seen quite often). The stator has 18 poles, 6 per phase. Each pole has (I don't know exactly) about 20 turns of copper wire on it. Between the phase outputs of a delta wound system you will have 120 turns. Because of the hot spot in the engine, the copper winding's insulation starts to fail after some time. Most likely that will be somewhere from one layer of windings to the next layer on a pole. This usually happens only under load and when the unit is hot. Imagine a few of these shorts in between the phase outputs. You will have not 120 turns but say 50 or 60. The complete charging system will still be able to reach 14.4 V DC, it is rated for about 400W. When you have a transformer with only a few thick windings, you will get a low voltage but higher current output. The same happens in the VFR Delta stator. Those 60 turns will give a much lower Vac but a much higher Iac. And diodes in regulator/rectifiers don't like high currents. If they are rated for 35 Amps, as most diodes are in this application, they can handle that whenever they get sufficient cooling. When they run hot, the max current they can handle drops down quite a bit, which makes dissipate even more heat, and finally one of the diodes fails! Electrex stators are wound in star. The total power output is about the same as the original (lower Iac times higher Vac makes about the same... I know this is simplified, there is more to it....). But there are always two phases in between the phase connections. (=240 turns) The Vac is higher, and the Iac is lower. Even if there would be a short in between some layers of turns (I haven't seen that happen) you still wouldn't have the current output of the original stator, which is what destroys regulator diodes. So far this is still unproven, but seems correct. It is difficult to prove, as you need to check the original stator for shorted windings whenever the systems is under load, and very hot. And it doesn't need to do it all the time even! Bikes that have had a few failing RR's stopped frying them after replacing the stator. One last thing: Problem #3:The output of the Voltage Regulator/Rectifier (VRR) is fed through the wiring loom and some sort of junction box to the battery. Make sure you have perfect connections here. I found a number of problems with voltage drops over these lines. Check the fault finding chart on http://www.electrexusa.com. It will guide you through the process. The best thing to do, if you see any voltage drops in between the VRR and battery (we are talking high current here, so any bad connection will give a significant voltage drop) is to feed the output of the VRR straight to the battery terminals using a (good quality) inline fuse.>> Hope this is helpful to everyone.

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!

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.

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.

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.

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?

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.