mrmach5
CB750 Enthusiast
This goes back to September 3rd,
So recently, My 80 F stopped charging , I was able to get it home before it quit. After running several tests on the stator, and rotor,,,,,,, the rotor failed the test. I purchased a new rotor
Installed then tested running voltage, and looked great 13.7 - 14.4 . A week or so later took it out for a nice long ride. This time not so lucky, it quit on me a couple miles from home.
I installed a new rectifier- regulator and checked connections. This morning hooked up a temporary volt gauge to monitor it while test driving. When I first fired it up it was making 13-14 volts at RPM, after riding 6-7 miles it was down to 12.3-12.5, barely battery voltage.
So it seems whatever is happening is tempature sensitive. I'll be getting out the multi meter and start the process again. I'm not ruling out the rotor even though its brand new.
Also the brushes look great , bike only has 6,500 miles on it.
Sept 10th
Installed a new stator and tested charging and looked good. Again on the test drive I had a voltage gauge up on the dash to make note of charging voltage at different RPMs . At a steady 4k it was making just shy of 14v. About 15 minutes into the ride , the voltage output was dropping and eventually barely making positive voltage at 3-4k rpm, and none at idle. Made it home ok ,and back on the lift. Removed the cover and checked the rotor and measures at 7.8-7.9 ohms . The spec for these rotors is 5.0 ohms which is what it was when I installed a few weeks ago. I know that rotors that test below 5 ohms are considered bad, what about ones that test higher? With the new stator having no real effect on the issue, I'm highly suspicious of the rotor . Just because its new does not mean it can't be bad.
Oct 26th
So still not fixed . Originally the Rotor tested bad so I replaced with a new Electromotive. Suspected it was bad so they replaced it with another new unit. Same result , charges fine cold but once up to temperature it stops making acceptable voltage. I then tried a used Honda rotor that tested good. Same result.
So far I have replaced the rotor 3 times, the stator once and the regulator -rectifier twice , all with the same result.
I'm at a loss at this point, not sure what direction to go.
So recently, My 80 F stopped charging , I was able to get it home before it quit. After running several tests on the stator, and rotor,,,,,,, the rotor failed the test. I purchased a new rotor
Installed then tested running voltage, and looked great 13.7 - 14.4 . A week or so later took it out for a nice long ride. This time not so lucky, it quit on me a couple miles from home.
I installed a new rectifier- regulator and checked connections. This morning hooked up a temporary volt gauge to monitor it while test driving. When I first fired it up it was making 13-14 volts at RPM, after riding 6-7 miles it was down to 12.3-12.5, barely battery voltage.
So it seems whatever is happening is tempature sensitive. I'll be getting out the multi meter and start the process again. I'm not ruling out the rotor even though its brand new.
Also the brushes look great , bike only has 6,500 miles on it.
Sept 10th
Installed a new stator and tested charging and looked good. Again on the test drive I had a voltage gauge up on the dash to make note of charging voltage at different RPMs . At a steady 4k it was making just shy of 14v. About 15 minutes into the ride , the voltage output was dropping and eventually barely making positive voltage at 3-4k rpm, and none at idle. Made it home ok ,and back on the lift. Removed the cover and checked the rotor and measures at 7.8-7.9 ohms . The spec for these rotors is 5.0 ohms which is what it was when I installed a few weeks ago. I know that rotors that test below 5 ohms are considered bad, what about ones that test higher? With the new stator having no real effect on the issue, I'm highly suspicious of the rotor . Just because its new does not mean it can't be bad.
Oct 26th
So still not fixed . Originally the Rotor tested bad so I replaced with a new Electromotive. Suspected it was bad so they replaced it with another new unit. Same result , charges fine cold but once up to temperature it stops making acceptable voltage. I then tried a used Honda rotor that tested good. Same result.
So far I have replaced the rotor 3 times, the stator once and the regulator -rectifier twice , all with the same result.
I'm at a loss at this point, not sure what direction to go.