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Charging, once again

motogtp

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I have looked through the threads but didn't find a direct answer. '78 Super Sport with a new rectifier/regulator just to clean things up. I have 12.8-13.0V at idle but over 17V at 3,000 rpm. Just pulled the alternator cover and measured resistance at the leads. I have 7.2 ohms at the coil and 0.9 ohms at the stator. So the stator is bad? Would that cause the overcharge issue with the regulator? Just want to make sure I understand the relationship cause my initial thought would be that would lead to an undercharge issue. Thanks.
 
To get the .9 ohms at the stator did You pair up two of the three wires in different combinations and get the same reading?

Yup. The middle wire against each of the other two (separately) and the other two against each other. All read 0.9 ohms. Clymers says a good stator reads 0.2 ohms but the fact that all 3 combinations read the same thing has me confused. So are there 3 sets of windings on the stator?
 
Yes there are 3 windings on the stator each end of the windings are common to each other, I checked the output on My K2 15volts at 3,000 RPM,s which too is rated a little high, Seems 17volts would be sufficient to blow the speedo lights or at least blacken them rated at only 3.4 watts. I don,t recommend to anyone to change something out if it,s working but thats My opinion. Was this problem there before the updated regulator? I read there were alot of changes made on the 77 and 78 model including a larger amp battery, The prints for the charging system look very much alike. I will check back.
 
Thanks Dan. Doing a little more searching, someone posted that you should first figure the internal resistance of the multi-meter (touch leads together) and then subtract that from the readings you take at the wires. I didn't do that. I will do that tonight. I changed the regulator (prior to getting the multi-meter) because there was some evidence of excessive voltage as the main fuse was always warm. And I did once find a small drop of solder at the fuse end cap. In retrospect I maybe should not have made the change but this bike only wants to run a few miles before it slowly starts to bog down and then die. I am working through all the systems to eliminate each as the problem.
 
I have a dead stator also but I have a new battery and able to ride just over 100 miles before I don't have enough juice for the electric starter to work. I can still ride further if I kick start it.
 
Moto I,ve given more thought about the charging issue, If the battery will not take a steady charge the field output will stay in full opt. condition giving You a full output condition, Have the battery checked, If that checks out with a fully charged battery put Your multimeter on the volt position or use a test light and check the white field wire to ground while running You should get 12vdc+ at the connections at above idle. At a slow idle with no load such as lights and the battery still at full charge 12.5v the field voltage should drop to zero, If the field voltage never drops out I would suspect the regulator. I was also thinking a high voltage/amps could overheat the coils and cause a problem there also. Of course been wrong before on things but just a thought. Good luck
 
Dan, thanks for the feedback. The battery is new. I am thinking the regulator, too. All lights brighten a lot with the higher revs. I am waiting to hear back from CycleX on any tests I can run. Right now the battery is at 12.88V. Typically the voltage will drop a few tenths when it is started but still register over 17V when I rev it up. When cold it starts and idles well. Starting from a stop requires few revs. However, after a couple of miles it takes more revs and then starts to miss and lose power. Like you I think that the coils are being saturated at that point causing the power loss. If I let is cool down it starts like nothing was ever wrong but if still warm it will not run as long as when it was dead cold. If I hadn't tossed the original regulator and rectifier I would put them back. Arrrrrgh!
 
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