Stator Readings = Smoking Gun?

[Guest TheMadGamer]

Good Evening,

This is not what I wanted my first post to be about but here goes: Hi, I'm MJ (aka, themadgamer) and I'm a VFRholic. Oh, wait, that's for another meeting, anyway... I am the proud owner of a 1993 VFR750F.

I've been stealthily lurking, reading and learning for a bit now. I had a charging issue and based on my reading here indications were that the rectifier failed. Joshua squared me a way with a rectifier and VFRness (and some installation hand holding, thanks!!). My readings went from 12.7 @ idle/13.2 @ 5k RPM to 12.9 @ idle and 14.7 and steady as can be at 5k RPM. I also had the battery tested at the local Murray's, checked out okay. All good, right? Not so fast.

The bike starts fine if I'm riding daily but if I let it sit for more than a couple of days, it has issues. I returned Saturday from an all day ride. Went to work this morning and got lights and 2 or 3 failed attempts to start before it wouldn't turn over. I bump started her, rode to work, she was fine at lunch and fine to come home.

I took the battery to a Battery Plus tonight and they said it was fine so I read some more and decided to test the stator.

Tonight's measurements:

Battery Voltage = 12.7

Charging voltage at Idle = 12.9

Charging voltage at 5k rpm = 14.7

AC voltage from stator (with rr Unplugged) at idle = 20

AC voltage from stator (with rr unplugged) at 5k rpm = 65

AC voltage from stator (with rr plugged in) at idle = 10

AC voltage from stator (with rr plugged in) at 5k rpm = 12

Resistance between all 3 legs of the stator = _____ ohm (COULDN'T GET A READING, not sure if is my lack of skill with my analog meter or a failure)

I need to get a better meter so that I can confidently check resistance (I know, it could be that there wasn't any) and conduct the battery leak test. I couldn't discern the mA and Ohm scales.

So, should I stop what I'm doing and just order a stator?

Other thoughts?

Much thanks,

TMG

[jeremy556]

The bike starts fine if I'm riding daily but if I let it sit for more than a couple of days, it has issues. I returned Saturday from an all day ride. Went to work this morning and got lights and 2 or 3 failed attempts to start before it wouldn't turn over. I bump started her, rode to work, she was fine at lunch and fine to come home.

I took the battery to a Battery Plus tonight and they said it was fine so I read some more and decided to test the stator.

Sounds like you have something that is drawing down your battery when not in use. Set your multimeter to amps or milliamps and connect it in line with your battery with the ignition off. There should be minimal draw, like <10 milliamp

Tonight's measurements:

Battery Voltage = 12.7

Charging voltage at Idle = 12.9

Charging voltage at 5k rpm = 14.7

AC voltage from stator (with rr Unplugged) at idle = 20

AC voltage from stator (with rr unplugged) at 5k rpm = 65

AC voltage from stator (with rr plugged in) at idle = 10

AC voltage from stator (with rr plugged in) at 5k rpm = 12

Resistance between all 3 legs of the stator = _____ ohm (COULDN'T GET A READING, not sure if is my lack of skill with my analog meter or a failure)

Everything you posted sounds correct. The likely reason you couldn't get a reading between the stator legs is they have infinite resistance between them, which is what they should have. It should be the same reading as the meter gives you when the probes are not touching anything.

[Guest]

The bike starts fine if I'm riding daily but if I let it sit for more than a couple of days, it has issues. I returned Saturday from an all day ride. Went to work this morning and got lights and 2 or 3 failed attempts to start before it wouldn't turn over. I bump started her, rode to work, she was fine at lunch and fine to come home.

I took the battery to a Battery Plus tonight and they said it was fine so I read some more and decided to test the stator.

Sounds like you have something that is drawing down your battery when not in use. Set your multimeter to amps or milliamps and connect it in line with your battery with the ignition off. There should be minimal draw, like <10 milliamp

Yes, I am concerned about that and I will buy a better meter so that I can get a good reading.

Tonight's measurements:

Battery Voltage = 12.7

Charging voltage at Idle = 12.9

Charging voltage at 5k rpm = 14.7

AC voltage from stator (with rr Unplugged) at idle = 20

AC voltage from stator (with rr unplugged) at 5k rpm = 65

AC voltage from stator (with rr plugged in) at idle = 10 :fing02:

AC voltage from stator (with rr plugged in) at 5k rpm = 12 :excl:

Resistance between all 3 legs of the stator = _____ ohm (COULDN'T GET A READING, not sure if is my lack of skill with my analog meter or a failure)

Everything you posted sounds correct. The likely reason you couldn't get a reading between the stator legs is they have infinite resistance between them, which is what they should have. It should be the same reading as the meter gives you when the probes are not touching anything.

Jeremy, thanks for clarification on the resistance.

I wasn't sure if the AC Voltage readings with the rr plugged are what they should be, I thought they'd need to be higher.

Thanks,

TMG

[Guest]

A couple of electrical points...

Yes, the draw with the key off should be very low. <10mA sounds good. That is <0.01 Amps, or <1/100th of an Amp.

The resistance between the stator legs should be close to 0 Ohms, not infinity. Essentially, just like having the probes touching. What you really need to test that is called a milliohmmeter. Basically, a device descigned to test very low resistances, i.e. between 0 and 1 ohm. Sure, a digital multimeter or ohmmeter will be happy to show you 0.1 Ohms, or 0.2 Ohms, etc.., but there's no accuracy there. Honda specifies the test resistance of the stator coils to be between 0.1 and 1.0 Ohms, which are an order of magnitude different (i.e. 10 times different).. The problem is that a stator with 1 Ohm of resistance isn't going to work, but a good one may read that high on a multimeter just because of the resistance in the probe wires. I don't have the "right" equipment either, but I tested mine a little differently and got 0.150 Ohms per leg. That should be accurate to two places, i.e. it's definitely between 0.149 and 0.151, with a difference of 0.001 (1/1000th of an Ohm). For a regular multimeter, the smallest difference it can show would be between 0.1 and 0.2, with a difference of 0.1 (1/10th of an Ohm). So, I should be 100 times more accurate.

I'd say that those AC voltages don't look bad either. Here's why: AC voltage is sine wave with peaks and valleys. When you measure it, you're getting an RMS (Root-Mean-Square) value which will be lower than the peak values. It's sort of like an average, so even though you're seeing 10 to 12, it's really higher than that much of the time. You'd need an oscilloscope to see it.

[Auspanglish]

To check for the leak with key "off" that Jeremy mentions I believe you place the negative probe on the negative battery terminal and positive probe to any grounding point with the multimeter on Ohmms and report what you find...I believe for the VTEC the maximum current leakage is 2.5 mA = 0.0025 Amps... don't know for your model.

A couple of electrical points...

Yes, the draw with the key off should be very low. <10mA sounds good. That is <0.01 Amps, or <1/100th of an Amp.

The resistance between the stator legs should be close to 0 Ohms, not infinity. Essentially, just like having the probes touching. What you really need to test that is called a milliohmmeter. Basically, a device descigned to test very low resistances, i.e. between 0 and 1 ohm. Sure, a digital multimeter or ohmmeter will be happy to show you 0.1 Ohms, or 0.2 Ohms, etc.., but there's no accuracy there. Honda specifies the test resistance of the stator coils to be between 0.1 and 1.0 Ohms, which are an order of magnitude different (i.e. 10 times different).. The problem is that a stator with 1 Ohm of resistance isn't going to work, but a good one may read that high on a multimeter just because of the resistance in the probe wires. I don't have the "right" equipment either, but I tested mine a little differently and got 0.150 Ohms per leg. That should be accurate to two places, i.e. it's definitely between 0.149 and 0.151, with a difference of 0.001 (1/1000th of an Ohm). For a regular multimeter, the smallest difference it can show would be between 0.1 and 0.2, with a difference of 0.1 (1/10th of an Ohm). So, I should be 100 times more accurate.

I'd say that those AC voltages don't look bad either. Here's why: AC voltage is sine wave with peaks and valleys. When you measure it, you're getting an RMS (Root-Mean-Square) value which will be lower than the peak values. It's sort of like an average, so even though you're seeing 10 to 12, it's really higher than that much of the time. You'd need an oscilloscope to see it.

Nice... BTW my digital meter has two positions for Amps... one with a symbol like the one used for V AC and the other with a symbol like the one for V DC... which one should I be using? AC or DC?

[Guest]

To check for the leak with key "off" that Jeremy mentions I believe you place the negative probe on the negative battery terminal and positive probe to any grounding point with the multimeter on Ohmms and report what you find...I believe for the VTEC the maximum current leakage is 2.5 mA = 0.0025 Amps... don't know for your model.

Not quite. You would disconnect either battery terminal and wire the meter inline there as appropriate while having it set for DC milliamps. If you disconnect the postive terminal (Red), put the Red probe on the battery and the Black probe on the (disconnected) wire. Similarly, if disconnecting the negative terminal (Black). put the Black probe on the battery and the Red probe on the wire. That will get you a positive current reading on your meter. Lower is better.

Nice... BTW my digital meter has two positions for Amps... one with a symbol like the one used for V AC and the other with a symbol like the one for V DC... which one should I be using? AC or DC?

To check for a leak, DC. Between the stator and the R/R (the 3 yellow wires), is three-phase AC. Everything else is DC. The R/R is a Rectifier/Regulator, and a Rectifier is what converts AC -> DC.

[Auspanglish]

To check for the leak with key "off" that Jeremy mentions I believe you place the negative probe on the negative battery terminal and positive probe to any grounding point with the multimeter on Ohmms and report what you find...I believe for the VTEC the maximum current leakage is 2.5 mA = 0.0025 Amps... don't know for your model.

Not quite. You would disconnect either battery terminal and wire the meter inline there as appropriate while having it set for DC milliamps. If you disconnect the postive terminal (Red), put the Red probe on the battery and the Black probe on the (disconnected) wire. Similarly, if disconnecting the negative terminal (Black). put the Black probe on the battery and the Red probe on the wire. That will get you a positive current reading on your meter. Lower is better.

Nice... BTW my digital meter has two positions for Amps... one with a symbol like the one used for V AC and the other with a symbol like the one for V DC... which one should I be using? AC or DC?

To check for a leak, DC. Between the stator and the R/R (the 3 yellow wires), is three-phase AC. Everything else is DC. The R/R is a Rectifier/Regulator, and a Rectifier is what converts AC -> DC.

Uh... yeah... I knew that!!! hehehe... I knew it was Volts AC from stator de R/R and V DC from then on, but I don't know enough about electronics and was unsure about Amps... I mean, I didn't want to assume the obvious was true... as my 3rd grade teacher always said: to ASSUME is to make an ASS out of U and ME. i know there are no stupid questions but there are stupid people asking the questions... and I am officially "electronically stupid"!! I have to learn and relearn that stuff over and over again.. it never sticks... I must be allergic to it. Of course Ac = Alternating Current... and Current is Amps... right? Oh well... so much for trying to look smart... :fing02:

[IntAceptor]

I may have missed it but I don't think anyone told him to check resistance from the legs of the stator to motorcycle ground with the stator leads disconnected. That reading should be infinity, the same as the meter leads hanging in free air.

When a stator quits (fries) it usually shorts to ground.

[Tightwad]

I think your Stator is fine...I agree that it sounds like you have a current draw when the key is off that drains the battery down. I haven't had any other 3-4th gen owners say they had this problem, but it could be the way the VFRness is configured I guess....one way to tell would be to measure current draw, then disconnect the VFRness from the positive side of the battery by removing the fuse, and test the draw again.

[Guest]

I think your Stator is fine...I agree that it sounds like you have a current draw when the key is off that drains the battery down. I haven't had any other 3-4th gen owners say they had this problem, but it could be the way the VFRness is configured I guess....one way to tell would be to measure current draw, then disconnect the VFRness from the positive side of the battery by removing the fuse, and test the draw again.

Hey all, sorry about the delay with follow up, was out of town for a few days to pick up the new 2-Up mobile. Now I can have my VFR configured just for me and the Goldwing for us, win/win! and the Goldwing has it's first 1000 miles on it, wheee! Now to get Pearl back up and running for the fun stuff!

Anyway, I got a better meter.

Resistance amongst the 3 stator wires is .6-.7 ohms. There is continuity between each wire and ground on the bike.

Now about the leak test, I get nothing. To confirm I was doing it correctly, I even popped off the battery cover off the new Goldwing and did the test and got a reading of 1.6 mA. On my VFR I get 0.0.

Pre VFRness and NEW Rectifier I was definitely not charging the battery as evidenced by my readings.

I'll also add that the starter relay connector was toasty enough that I had to use the repair kit included with the VFRness.

Any further thoughts are appreciated.

:blush:

TMG

[Guest]

Resistance amongst the 3 stator wires is .6-.7 ohms. There is continuity between each wire and ground on the bike.

Those resistances between the stator wires are about all you can expect with the way you're testing them.

If there is continuity between any of those wires and ground, that's bad. The stator is shorting to ground and needs replacement.

[jeremy556]

Resistance amongst the 3 stator wires is .6-.7 ohms. There is continuity between each wire and ground on the bike.

Now about the leak test, I get nothing. To confirm I was doing it correctly, I even popped off the battery cover off the new Goldwing and did the test and got a reading of 1.6 mA. On my VFR I get 0.0.

Your resistance reading is in spec. There should be no continuity between any of the 3 yellow wires and ground.

You should get something if the clock is on, anything under 2.5ma is normal.

[Guest]

Resistance amongst the 3 stator wires is .6-.7 ohms. There is continuity between each wire and ground on the bike.

Now about the leak test, I get nothing. To confirm I was doing it correctly, I even popped off the battery cover off the new Goldwing and did the test and got a reading of 1.6 mA. On my VFR I get 0.0.

Your resistance reading is in spec. There should be no continuity between any of the 3 yellow wires and ground.

You should get something if the clock is on, anything under 2.5ma is normal.

D'oh, Jeremy, if only I could type. My resistance was fine and I did NOT have continuity between any of the 3 stator wires and ground. So the stator checks out.

On the other hand, my leak test result is still 0.0.

Stumped in MI

TMG

[jeremy556]

When you said 2-3 failed start attempts in the original post, what happened? Did the starter turn the engine for a few seconds and not fire? Did the stator slow crank, or did you hear clicking from the starter relay?

So far everything in your charging system checks out fine, and you stated you had the battery tested at 2 different places, so it should be fine as well.

I would start looking at the starter motor, relay, wiring, and battery ground connection.

[Guest]

When you said 2-3 failed start attempts in the original post, what happened? Did the starter turn the engine for a few seconds and not fire? Did the stator slow crank, or did you hear clicking from the starter relay?

So far everything in your charging system checks out fine, and you stated you had the battery tested at 2 different places, so it should be fine as well.

I would start looking at the starter motor, relay, wiring, and battery ground connection.

By failed attempts I mean that when I pressed the starter, the motor attempted to turn over a few times without starting the bike and each subsequent attempt became weaker but all the the attempts sounded weaker than normal as if in slow motion. Voltage also dropped quite a bit during these attempts. There were two different events when this occurred after the bike was not ridden for 2-3 days. Bump starting the bike fired it up each time and additional starts during the same day were fine.

Thanks,

TMG

[Guest]

OK, so your stator is not fried. Everything else just sounds like a discharged battery. The problem is that it happens after just 2 days of sitting. Furthermore, it's fishy that you can't get a reading during the leak check. Something has to be discharging that battery while it's sitting. If you were successful in getting a reading on the other bike, I can't see how the VFR would be any different. If it was a bad batt, I would guess that it wouldn't pass the shop's test. How about just disconnecting it between rides for a little while? If that works, it would rule out a few things.

As an aside, I actually have to do exactly that on my Jet Ski. My Seadoo has a fairly high draw when it's just sitting. It's a normal and known conditon, which will ultimately leave the battery dead between riding days as they may be more than a week apart sometimes. So, I installed a high-amp switch on the battery which let's me disconnect it completely after each day. I wouldn't consider that to be an option for a bike, nor should it be necessary, but the concept may be worth a try.

[Guest]

OK, so your stator is not fried. Everything else just sounds like a discharged battery. The problem is that it happens after just 2 days of sitting. Furthermore, it's fishy that you can't get a reading during the leak check. Something has to be discharging that battery while it's sitting. If you were successful in getting a reading on the other bike, I can't see how the VFR would be any different. If it was a bad batt, I would guess that it wouldn't pass the shop's test. How about just disconnecting it between rides for a little while? If that works, it would rule out a few things.

As an aside, I actually have to do exactly that on my Jet Ski. My Seadoo has a fairly high draw when it's just sitting. It's a normal and known conditon, which will ultimately leave the battery dead between riding days as they may be more than a week apart sometimes. So, I installed a high-amp switch on the battery which let's me disconnect it completely after each day. I wouldn't consider that to be an option for a bike, nor should it be necessary, but the concept may be worth a try.

Yeah, the inability to get a reading on the leak test disturbs me. I don't want to luck into a solution, I'd like to know. I'll have to do some more research on potential causes of that since electrical stuff isn't my forte but I am patient and willing to learn.

I put the battery on the tender last night, disconnected it this morning. Voltage after disconnect 13.3. Two hours later it was 12.7. I have to go out of town for a couple of days so I'll have my SO check it daily for me just to see how it changes while I'm gone while I ponder next steps. I was trying remember when I bought the battery and I can't remember. My SO believes it is the battery that was in the bike when I bought it in 2004. If so, yikes, maybe I'll just buy a new one and start the trouble shooting from there.

The whole leak test thing still bothers me as well as this NEW draining behavior AFTER I installed the new rectifier/VFRness/relay fuse panel. Maybe I changed too many things at once or did it incorrectly, heh. :laugh:

I'll order a new battery and continue trouble shooting when I return.

Thank for all the input so far!

TMG

[VFRnGTP]

What a convenient thread. I'm having the same problem with my '04 ABS model. I'd have to go back and re-take all my readings, but basically, I've got 2.5mA draw (spec) with the VFR off. I can ride it every day and nothing is wrong. I can leave it sit overnight or for a day or two and it won't start; sometimes a week will do it. I had the battery tested by two shops, and they both said the battery was fine. 1.0 ohm spec resistance across the stator wires last I checked, which was a while ago.

I'm thinking that my R/R is going. I do notice that my Vdc reading while running will go down to ~12Vdc while at idle sitting at a light with the cooling fans on. I stopped riding around with High-beams and I unplugged my Stebel a while back to see if those were the problems and it just prolongs the inevitable.

Any thoughts on this? Seems like the same issue TMG is trying to solve...

Cheers,

VFRnGTP

edit to add: my battery is circa Jan'09 model YTZ14S Yuasa brand. Old battery was just plain dying/dead.

[spud786]

Only thing I'd add, on the stator wires to ground test , use a very high ohms scale, your sending current through those probes to get a reading. a low ohms scale may not get you a reading even though your stator has a short to ground.

The highest scale on ohms is the best to use, you should get no continuity at all. This is where a mistake can easliy be made in troubleshooting a stator, when a low range setting is selected.

[Tightwad]

If your battery drains while sitting disconnected, it is bad. 2004 or older for a battery is pretty darn good, I would replace it and test from there.

[VFRnGTP]

If your battery drains while sitting disconnected, it is bad. 2004 or older for a battery is pretty darn good, I would replace it and test from there.

...I'll update my post, but for my '04, I replaced the battery in January (or thereabouts) of this year (2009) because my original was done. I've done some amount of reading here, and I have it in the back of my mind that I may have helped toast my charging system trying to keep the old battery around, charging a dying battery and all...

[Guest]

If your battery drains while sitting disconnected, it is bad. 2004 or older for a battery is pretty darn good, I would replace it and test from there.

Yes, that is what I ended up doing. I bought a new Yausa battery and hooked everything else up. I rode it for a couple of days, then let it sit for 10 days while out of town. It was 38 degrees one morning and she fired right up for my ride to work :fing02:

I got to ride for another few days and then I've been out of town for a couple of weeks and so I just got her ready to be put up for the winter

I do believe the issue was the battery. Time will tell, thanks to everyone for all their help.

Stay Safe!

The Mad Gamer

(MJ)

P.S Oooo, web site has been spruced up! Nice to be back in town and have some time to peruse the forum. I love my VFR and look forward to many future fun exchanges.

[mechdziner714]

9 times out of 10 its the battery.