Ok I have a 1990 CBR 1000f and it has an internal alternator. My questions are:
1: How do you test the alternator to see if it is charging?

2: Does the bike have to be in gear and in motion for the alternator to charge the battery? cause i know it doesn't charge at an idle.

Your input is appreciated Thankyou

 

It should be charging at idle. If you use a volt meter, hold it onto your battery terminals, take a base reading with the bike off. Start the bike, and the volts should increase. Rev the engine to around 2000 rpms, and it should be charging at 14.2 or so volts. Motorcycle engines charge at idle, just not as much as they do at 2000 rpms, and most of the spec readings are taken at 2000 rpms. So if your not seeing any change at idle, there may be an issue.The bike does not have to be in gear or in motion to charge. If at 2,000 rpms, your charging at least 13.5, and no higher than 14.5, the stator is good. If its lower than that, the stator will need to be looked at. If its higher than that, the rectifier may not be doing its job. Keep in mind though, the voltage can be higher than 14.5 if the battery is not fully charged. These readings need to be conducted on a fully charged, known good battery. If the battery is weak, it can mess up the readings.

If its not charging, then you can inspect your stator. With the engine off, your going to measure the resistance across the 3 leads of the stator. Im sure what the resistance of your model should be,(a call to the dealership or download a manual for your bike) but most are within .4-.7 range. The more important part is that all 3 leads are within a specific range to each other. A difference of .2 is usually a sign of a bad stator. Or, no continutiy at all is also a sign of a failed stator.

If the stator checks out, it may be time to replace the rectifier. Im not sure of a way to test the rectifer. Maybe someone else can chime in if there is a test for the rectifier. Usually, the rectifier is culprit if everything else checks out ok. Such as connections, stator... ect.

 

Thankyou for the input it is very helpful. As far as the rectifier is concerned I contacted a honda service center and they informed me that the only way to test the rectifier is to test the charging system itself no real way to test the rectifier itself. Figured I'd put that out there for anyone else that needs to know. Thanks again you guys are awsome ride hard.