A bit long - but I think the details matter if someone's trying to help!
I started a thread about the fuel indicator light because I was sure I ran out of gas and the light didn't work. Forget that....I probably wasn't actually low enough for it to come on, and troubleshooting that came out fine.
The fuel pump seemed like it was working sporadically, so I checked the fuel transfer relay, fuel cutoff relay and they seem fine. Voltage directly to the pump kick started it. Bike still died after about 15 minutes and 10 miles of slow speed, high speed, and figure 8 practice. Just made it home.
I took the fuel pump out of the equation, went straight from the filter to the carbs. Same result, about the same time and distance. I actually rode exactly the same route, and as I approached home it seemed good so I road for a few more minutes before it started to die.
So I know for sure it's getting fuel, I'm pretty sure it's electrical, and it takes about the same amount of time each time to die completely.

What's interesting is that when it dies, the battery will barely turn it over. After a while (20-30 min maybe) it's strong enough again, but not for long if it doesn't start right away.

I'm not usually this patient or diligent, but I actually went through all the steps in the service manual except the one I'm not equipped for, which is load testing the battery.
1. I did the current leakage test: Within spec, at exactly 0.1mA
2. I checked the alternator charging coil: Resistance was 0.6 or 0.7 ohms between each connector. Spec is 0.1 to 1 ohms.
3. I measured battery voltage and charging voltage. The battery wasn't completely charged, so it was 11.96 volts. But when I started and ran it - from idle up to 5k, the charging voltage was also 11.96 volts. The standard is this:
Measured voltage<charging voltage<15.5V. I wasn't sure if the two voltages being equal was okay (because it's less than it should be anyway), but I don't think so. According to the manual, if it's correct it's a faulty battery. Keeping that in mind, I still moved on to the next step as if it was incorrect.
4. I inspected the r/r harness. Battery voltage at the red/white, green was ground, and the proper resistance across all the yellows, no continuity between ground and yellow.
5. As an extra step, I tested that R/R (from Rick's) and the OEM one (I replaced it just to be safe) and tested them. Both were good.

Since the battery wasn't quite charged for the testing last night, I left it on the charger and tested it this morning. Battery voltage was 12.5V, charging voltage at about 3K rpm was only 12.2V.

So the issue is this - if the rest of the charging system checks out, but the battery is toast, will it reduce the voltage in the charging system? The R/R prevents the battery from being overcharged, but if the stator and the R/R meet spec and the charging voltage is still low, is that because of the battery?

I've already ordered a battery, but it's driving me crazy not being certain. I can put a new one in and ride it for 20 minutes and figure it's great - then it dies on the way to work again. I'm worried that despite the stator meeting the resistance test specs, it's not putting out enough. The old battery is only about three seasons old, but it has been drained completely (couple of months ago) and I ride daily, in heavy traffic, a lot of time spent at idle. A toasted battery makes sense.

 

Given that you've worked thru the troubleshooting procedures & given your results, IF indeed is as you report, then it does sound like a battery issue.

Replace the battery & report back.

 

Or at least test your battery. Most places do it for free here

 

I figured with the abuse the battery has taken, and all signs pointing to the battery, I would just risk it and get a new one.
I ordered a Shorai - so I'm really curious to see how it works out. It's on the truck now for delivery today...

 

I just cant bring myself to buy a shorai. Its like buying 3-4 batteries but only getting one

 

got same problem. Rele-regulator was my problem. in idle mode give me 12.1,
@ 5000rpm 12.4 but it is not enought. it must be something like 13.8-14.2.
Change regulator and everything is ok.
o, i used reg from cbr 900. it is stronger and with better cooling.

 

Put in the new battery - LOVE this battery!
Went for a ride, it was dead in 15 minutes.
Retested everything. Measured 8.6Volts ac from each stator wire. All seems good.
Got it running again - charging voltage only barely over 12v.
Swapped out the two month old r/r for the old stock one on the parts shelf. Charging at 13.7 volts. WTF?

I started having trouble in June that was very similar to a fried R/R (been through it on an F2, F3 and now this one), so I swapped it out for a new one. Recently did a bunch of other regular maintenance becuase the air filter was disgusting....and now I realize why the battery was so weak. I've been discharging it every day, and barely charging it enough to keep it running. THe clogged filter was certainly a factor, but it was the classic bad r/r story, with a twist. If I had just left the stock one in back in June, and figured out the other issues it probably would have been fine.

It ran fine on the test run, battery was 13.6v when I parked it. Started it several times and shut it down again. That battery recharges very quickly.
So measuring the R/R for resistance and continuity resulted in the same measurements for both units, but clearly one is not working quite right. I didn't consider it because it was new. I should have tried that swap three days ago. Another lesson learned.

 

Your first description sounded like R/R but you said you'd done the checks. What R/R exactly were you running w/ all this trouble?

I swapped my troublesome orig oem R/R (flat) yrs ago for the upgraded revised finned factory R/R & its been great.

 

I don't know where I went wrong with the checks. I probably ASSUMED something. Ironically, one of the things I did was pull the R/R and compare all the readings to the OEM one. THey were the same, so that would be both good or both bad.

I guess the problem was that I had just this "upgraded" one in June, and was convinced it wouldn't be the problem. THere's another mistake - when I installed it, I never checked the charging voltage to ensure everything was okay.

Maybe it was, and this was just a recent failure. Either way, I should have been more suspicious of it right from the start, because the symptoms were so familiar.

The R/R was a finned one, from RM Stator in Quebec. I'm sure I bought one from there for one of my other bikes. I think I'll order the updated factory one, then still keep this original one for an emergency.

It was still a great excuse to get this awesome new battery, though!