Battery not charging above 1500rpm
#11
12-11-2011 | 07:38 AM
Senior Member
Joined: Oct 2006
Posts: 3,106
From: Misawa Japan
1st Gear Member
Had a brand new battery lose it's charge after a day out on fire roads. I checked the battery voltage after charging back at the garage and it was around 12.6V. When idling it goes up to about 13.6V and drops below 13V when I increase the revs.
From the service manual I checked if I was getting 45V from the alternator. I do on idle and then it drops down to nothing when increasing revs. Bike has only done 800 miles but has been dropped a couple of times. My assumption is that it's a faulty rectifier.
Any thoughts?
Also checked the timing with a strobe and the timing mark is about 10 degrees to the left of the top notch when at 4000rpm....it sure sprayed out some oil as well.
I'm not really confident I know what I'm doing so any advise would be greatly received.
BTW, setup is 351 kit and pumper carb installed.
From the service manual I checked if I was getting 45V from the alternator. I do on idle and then it drops down to nothing when increasing revs. Bike has only done 800 miles but has been dropped a couple of times. My assumption is that it's a faulty rectifier.
Any thoughts?
Also checked the timing with a strobe and the timing mark is about 10 degrees to the left of the top notch when at 4000rpm....it sure sprayed out some oil as well.
I'm not really confident I know what I'm doing so any advise would be greatly received.
BTW, setup is 351 kit and pumper carb installed.
The best course to take is to pull the rotor and stator out to inspect them. A damaged or failed rotor will be obvious because it's usually a material failure of some kind (magnets coming loose, etc).
With the stator, you need to check for any loose connections and read out the coils. The book should provide resistance values.
Good luck.
**since the problem happens dynamically, you'll have to wiggle whatever connections you can see while making taking your reading IF you don't find something obvious like bad solder joints, etc.
Last edited by tremor38; 12-11-2011 at 07:42 AM.
#12
12-11-2011 | 03:19 PM
Thread Starter
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Junior Member
Joined: May 2010
Posts: 8
Thanks....I changed the rectifier before seeing this....must admit I was praying that I wouldn't have to check the stator.
Looks like you are right.....still have the problem. Good news is the new rectifier brings charging at idle up to 14.1v
I'll let you know how I get on.
Looks like you are right.....still have the problem. Good news is the new rectifier brings charging at idle up to 14.1v
I'll let you know how I get on.
#13
12-11-2011 | 04:26 PM
Senior Member
1st Gear Member
Joined: Sep 2011
Posts: 379
From: Detroit, MI
wow i feel dumb i didn't even realize you were measuring ac, makes sense its not a rectifier now lol, sorry for the bad advice... i needa read more carefully. for some reason when i originally read your post i figured you were measuring dc output, then again 45v would be a little high :-)
#14
12-12-2011 | 01:32 AM
Thread Starter
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Junior Member
Joined: May 2010
Posts: 8
Well...not sure what I did....checked all connections and engine earth. Now I'm getting over 110v AC from the stator when over 6000rpm.
Battery is showing 14v at idle dropping to 13.6v at higher revs....is that normal?
Battery is showing 14v at idle dropping to 13.6v at higher revs....is that normal?
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