My bike is still not charging....

So after fixing my frame I was able to put about 100miles on it before the battery died. I assumed that the battery itself had given out being ~4 years old and never sitting more than 48hrs with being cycled. Plus I put a meter on my heated gear plug to see if the voltage was increasing as the rpms climed, it did. I also assumed this because in 30,000 miles I haven't had a single battery/charging issue until the bike sat for 3 months. Oh and one more reason that lead me to beleive that it was the battery was the fact that the bike will run fine once started so obviously the ignition/fuel system is getting juice to run the bike. So I bought a new battery and 100miles later I'm in the same boat. And again the bike, once started either by pushing it off or hooking up a trickle charger will run fine, it's just not charging the battery for what ever reason. These problems only came up after messing with the frame, so I pull the tank and seat to check any connections that I possibly missed and found nothing. So now I'm kind of thinking its a ground issue, as in maybe when I painted the frame something is not grounding now. So does anybody know of any grounding straps on that side of the bike? Or have any ideas?

measure your stator output, charge the battery, disconnect the stator from the R/R, start the bike and measure the 3 output voltages across the terminals at idle and at 4-5k rpm

it could still be producing some power, but if one of the coils burnt out then it won't be producing enough

is there a fuse or some other link that goes to the battery? something that would allow the stator to power the bike but not the battery?

yamihoe said:

is there a fuse or some other link that goes to the battery? something that would allow the stator to power the bike but not the battery?

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I'm thinking something similar to that, or a ground that would cause the same thing.

And at idle it was putting out about 11.4v, and around 5k it was ~12.7 I think

that voltage sounds low as measured from the battery, it should be around 14V

test the stator directly disconnected form the R/R and running, it's an easy way to be sure. Make sure your voltmeter is set to AC. You can also measure resistance with the engine off, make sure there's no continuity to ground from the stator wires.

AC output should be in the 30-90V range

if the stator checks out then it could be your R/R

greg said:

that voltage sounds low as measured from the battery, it should be around 14V

test the stator directly disconnected form the R/R and running, it's an easy way to be sure. Make sure your voltmeter is set to AC. You can also measure resistance with the engine off, make sure there's no continuity to ground from the stator wires.

AC output should be in the 30-90V range

if the stator checks out then it could be your R/R

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Mine is the same, 14.0 V when riding.

Test grounds/connections as you are doing. Load testing the battery will not hurt as even a new battery can fail.

Test stator with ohm meter set to 1x range. Spec. reading should be .22 to .34 ohms. on each three legs of the stator.

There is no data for testing voltage in the service manual. The stator is classified as a magneto. It uses positive and negative poled magnets to produce alternating current in the stator windings. Because of this and the fact that there is no load except the very high input impedance of the meter, the readings may not tell us what we really need to know about the stator condition. Phase relation changes with RPM of the motor and that may not reflect what voltage would be under the slightest load. Measuring output this way is dependent on frequency, phase of interacting positive and negative wave forms as well as inductive reactance. With the ohm test you should get a better picture.

If connections, battery and stator pass it's time to suspect Regulator/Rectifier or it's connector. Check R/R connector for burned contacts.

ChevyFazer said:

I'm thinking something similar to that, or a ground that would cause the same thing.

And at idle it was putting out about 11.4v, and around 5k it was ~12.7 I think

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Keep in mind that if your battery is low on it's charge it has lower internal resistance. How this translates is it puts a greater load on the charging system.

When the load is increased you will see a lower voltage. As the battery charges , it's internal resistance increases and the load decreases which then lessens the charging system load. This allows increased voltage.

Voltage is just part of the picture and can help trouble shoot problems but the charging system and battery have 2 very important values, voltage and current.

What I found after chasing problems with my bike is:

Battery, should charge to 13.15V or so with trickel charger.

Stator - difficult to find meter with a low enough resistance scale to check so I checked open circuit. It is a 3 phase machine and should register the same voltage between all three wires. Mine had good voltage on two legs but the third was much lower. By leg I mean for say three wires A B C, one leg is A to B, a second is B to C and the third would be C to A.

Regulator - if battery is charged and stator working it should indicate 14V at say 4,000RPM (less at idle).

After I put mine back together that is what it does - I had a burned coil on the stator with several cracks. Hey Motogiro if you PM me your address I'll send you (for free!) the burned one for a paperweight or a rebuild project. Not a free lunch though.

Those voltages I mentioned were checked the extremely lazy way, through my heated gear plug lol so I haven't actually checked it at the battery. I was going to mess with it yesterday but I ran the SOB outta gas on my way home from work!!!! My fuel gauge has never worked so I go by miles and had completely forgot about my unhooking my battery over the weekend...

So needless to say I didn't feel like messin with it lol
View attachment 46507

Question though, y'all don't think it would have anything to do with a ground?

I ask because I think it's too coincidental that this happened after reinstalling a freshly painted frame where I never had any charging issues before I messed with it?

Do you remember removing any wires directly off the frame itself?

I don't know where main ground, grounds are, anyone?

The voltage regulator is bolted away from the rt side frame, maybe double check the connector for any melting, corrosion, tightness to the frame(ground)?

Hey Bro, I was just thinking... Did you disconnect everything when you perform the welding? Might have fried something???

I know on race car when we weld like that we always disconnect ECU and battery to be safe.

TownsendsFJR1300 said:

Do you remember removing any wires directly off the frame itself?

I don't know where main ground, grounds are, anyone?

The voltage regulator is bolted away from the rt side frame, maybe double check the connector for any melting, corrosion, tightness to the frame(ground)?

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I remember a ground to the frame but I don't remember where it was. IIRC there were more than 1 wire tied to the point. There may also be more ground points and locations on the frame for grounds.

Since the problem is charge related you should be able to ring every part of the charging system that is supposed to be at ground potential to see if it's properly grounded. Any part that is suppose to be at ground should ring out to the negative lead of the battery. No part of the stator needs to be grounded but the case of the stator is bolted to the engine so it is at ground potential. The stator windings should read .22 to .34 with an ohm meter. No leg of the 3 stator windings should show continuity to ground or casing of the stator/engine.


I keep seeing reference to measuring the stator voltage. I hope I don't offend anyone but this is not the recommended test. It is not recommended as a test for many reasons and they would require an understanding of theory that we are not all familiar with so I will leave out the lengthly discussions on inductive reactance, impedances, etc. etc.


When testing the stator Yamaha recommends using the ohm meter set at 1x range. Some ohm meters are auto ranging. 1x or x1 is just the lowest range on your meter which is the default on an auto ranging ohm meter.

Measuring the voltage coming out of the stator can give you false readings. Your meter is a high impedance device and can register voltages coming from the stator that mean nothing because you are looking at a device that needs to produce power. Power equals voltage times current. Unless you are measuring current or at least have the stator under a known load a voltage test can be very inaccurate. The manual says to measure resistance. They are not guessing and say to measure resistance.

We had a member measuring voltages from a stator and he got equal voltage measurements from all 3 legs but his system wouldn't charge correctly. He had replaced his burned stator with a new one. he had also replaced the regulator and battery.

When he would measure voltage it looked good. When he did the resistance check, it was off so investigation of the part found that they gave him a stator that bolted on but was the wrong stator and could not produce the voltage x current needed.

Happy hunting!

I don't remember disconnecting any wires from the frame but then again I was a half a case in when the frame actually came off lol I have a assemble manual I might have to check out and see if I can see any

An Marty I actually removed the entire frame half from the bike before any welding was done for that very reason
View attachment 46508

I took a look through the manual and found thisView attachment 46509View attachment 46510

#4 is what I'm looking at and I do remember working in that area so ill take it apart do some of the test y'all suggested and see where it goes

ChevyFazer said:

I took a look through the manual and found thisView attachment 46509View attachment 46510

#4 is what I'm looking at and I do remember working in that area so ill take it apart do some of the test y'all suggested and see where it goes

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Have you checked connector 5 and associated wiring?

Connector 5 is a good one to check. #4 is a pain to get to, I was looking at it the other night chasing my rough idle problem. You can see it from the left side of the bike, it's on top of the transmission area. Should be easy to visually inspect. Just kind of difficult to get a t-handle on it to tighten.

It's a pretty simple system, battery, stator and voltage regulator. Check the battery, if it is fully charged then check the charging voltages, then move to checking the voltages from the stator. The stator is a three phase AC generator. The voltage regulator converts it into DC and regulates it to about 14V max. I'll study the diagrams to see what I can figure out about the ground being a cause.

Looking at the wiring diagram it looks like there are several points where the ground or negative side of the electrical is using the frame/chassis for a conductor. There are 5 wires that connect to the voltage regulator, three are white and those go to the stator. The other two are a red and a black. The red connects to the battery and the black appears to go to a ground point - don't know where that would be though. If it is not connected then the bike would not charge. I checked the case of the regulator to see if it was connected to any of the connector pins and it is not so the ground (black) would be the ground connection. This is what I see from the wiring diagram, you should verify what I'm saying to make sure I didn't confuse anything.

PhotoAl said:

Connector 5 is a good one to check. #4 is a pain to get to, I was looking at it the other night chasing my rough idle problem. You can see it from the left side of the bike, it's on top of the transmission area. Should be easy to visually inspect. Just kind of difficult to get a t-handle on it to tighten.

It's a pretty simple system, battery, stator and voltage regulator. Check the battery, if it is fully charged then check the charging voltages, then move to checking the voltages from the stator. The stator is a three phase AC generator. The voltage regulator converts it into DC and regulates it to about 14V max. I'll study the diagrams to see what I can figure out about the ground being a cause.

Looking at the wiring diagram it looks like there are several points where the ground or negative side of the electrical is using the frame/chassis for a conductor. There are 5 wires that connect to the voltage regulator, three are white and those go to the stator. The other two are a red and a black. The red connects to the battery and the black appears to go to a ground point - don't know where that would be though. If it is not connected then the bike would not charge. I checked the case of the regulator to see if it was connected to any of the connector pins and it is not so the ground (black) would be the ground connection. This is what I see from the wiring diagram, you should verify what I'm saying to make sure I didn't confuse anything.

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Yes, the ground could definitely be the cause. From that pictorial it looks as if the main ground is tied to the engine casing. Chevy was thinking he may have lost the ground because of the frame removal but the main ground looks like it's tied to the engine so I wouldn't suspect that as the first problem but it never hurts to check your wiring before any other trouble shooting.

If the bike was started and the battery terminal were disconnected to see if the charging system worked the regulator could be spiked and damaged immediately. People still do this today, left over from the old car generator days to see if it's a battery problem or a charging problem. Never do this with your bike or car. The bike's charging system needs to have the battery in circuit.

Below is diagram of a typical MC charging system. Notice the diode cathodes are at ground as well as the regulator.

PhotoAl said:

It's a pretty simple system, battery, stator and voltage regulator. Check the battery, if it is fully charged then check the charging voltages, then move to checking the voltages from the stator.

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Check the stator with an ohm meter. The AC waveform varies as RPM varies. Factors such as inductive reactance, frequency of the AC as well as it's wave form are so variable that adding that to your AC meter's specification and capability to measure at different frequencies is going to give every one a different reading as well as the AC characteristics of each stator. There are too many variable with no standard to go by by. The ohm test works great!

Agree, only reason I suggested is that I had trouble checking the resistance with my ohm meter and the voltage difference in the three phases was pretty obvious - two had a bunch and one had none. After that I carefully pulled the stator cover off and then it was obvious. To properly measure AC voltages of different frequencies you need a true RMS meter and most meters that are affordable are not.