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Discussion Starter #1
My battery died while out riding. I recharged and tried again - dead within a day. After verifying the battery holds a charge when off the bike, it was time to crack open the shop manual:



1. Check the main fuse - there is only one 20a fuse (the other is a spare) located under the right side cover.

- Fuse was OK visually and by measuring continuity

2. Check the battery

- Did it with the battery charger (it is a "Smart charger")

3. Check the charging voltage at the battery - should be 14 - 15 volts at about 5000 rpm

- I actually pulled the battery out and tested on the leads: reading was 9 volts - that's not good!

4. Check charging coil resistance test - Should be 0.3 - 0.5 ohms (or basically the continuity meter should "beep")

- No beep. something wrong with coil



Now I should mention that it took me a while to find the charging coil leads in the wiring harness. The manual says the wires are white and yellow, but my 2005 didn't have those colours. I also checked the supplement, but there was no mention of the charging system. So it was time to crack open the case. Looks like the charging coil is the bigger single coil at the bottom of the picture. So the wires are bluish-green and brown:







Tracing those wires to the harness, they are in the grey connector:







But then I noticed something else, there was some resistance between the battery leads when the key was in the Off position. Pulling connections, I found the rectifier was the culprit. So the rectifier was leaking voltage from the stator to ground.



So maybe the rectifier burned-out the charging coil on the stator - and maybe the stator fried the rectifier. Either way, I'm shopping for a new stator and a new rectifier
 

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Discussion Starter #2
So I replaced my CDI and now my battery is charging again.



Looks like the 2001 and newer shop manual supplement is missing the charging circuit troubleshooting process. So here is my take:



1. Check the main fuse - there is only one 20a fuse (the other is a spare) located under the right side cover.

2. Check the battery

3. Check the charging voltage at the battery - Should be 14 - 15 volts at about 5000 rpm

- If the voltage is wrong, replace the CDI

4. Check charging coil resistance test - Should be about 800 ohms



In the end, my CDI and rectifier were faulty. Coil was fine (of course, replacing the rectifier and CDI is a 5 minute job that doesn't require tools - coil was a 90 minute job that requires draining all the oil!)
 

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Thanks for the follow up. Good info. Glad you got her back on the road.
 

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So I replaced my CDI and now my battery is charging again.



Looks like the 2001 and newer shop manual supplement is missing the charging circuit troubleshooting process. So here is my take:



1. Check the main fuse - there is only one 20a fuse (the other is a spare) located under the right side cover.

2. Check the battery

3. Check the charging voltage at the battery - Should be 14 - 15 volts at about 5000 rpm

- If the voltage is wrong, replace the CDI

4. Check charging coil resistance test - Should be about 800 ohms



In the end, my CDI and rectifier were faulty. Coil was fine (of course, replacing the rectifier and CDI is a 5 minute job that doesn't require tools - coil was a 90 minute job that requires draining all the oil!)


I would like to add that IF the charging voltage is "wrong"...it may not be necessary to change the expensive CDI.

It's happened to me where the charging voltage was incorrect, and the culprit was the BATTERY.



An easy way to check a battery is to measure the Open Circuit voltage (battery sitting on the bench with nothing connected to it). Should read about 13 Volts.

Then do a Load Test (connect heavy load like compressor or headlight) while measuring the voltage. It should drop slightly, but then recover fairly quickly when the load is removed. If the voltage drops below 10 volts...you have a dead or dying battery.
 

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The CDI system is self-contained and is completely independent of the charging system and battery. It has no interest in what your battery, stator or regulator may or may not be doing. Its job is solely to make sparks.
 
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