Topic: 350 battery issue?

[2strokeTrush]

Hey guys so im new to the site, i purchased a 73 350f as my first LEGAL street bike and im having a issue charging.  Sorry if this question has been asked but i couldn't find anything really helpful when i searched.  If i charge the battery she will eventually run herself down. if i let her sit and idle while the battery is low it will eventually run down all the way till the bike wont run. What am i missing here? bad stator? Rectifier? any help would be awesome guys! Thanks! Tyler from Baltimore!

[flybox1]

Tyler, have you done any maintenance or overhaul/cleaning of your electrical system and contacts?  its a good place to start.  clean and treat with dielectric grease - every bullet connector.  refresh your fuse panel.
download a copy of the shop manual from the site, and get yourself a copy of the clymer manual.
it details testing and cleaning your VReg.  probably where you'll spend some time.
I ran through this same issue with my 350F.  Vreg work now, wont help much unless your harness/fuse panel is in good shape.

read through this thorough post by TwoTired.
http://forums.sohc4.net/index.php?topic=117727.msg1329353#msg1329353

welcome to the forum, btw 

[raymond10078]

At idle - the battery is not getting charged.

So . . . letting the bike run at idle for extended periods will indeed drain a battery.  That is expected.

Does the battery charge when running down the road or the engine speed is raised to - like 3000 or higher?

[flybox1]

At idle - the battery is not getting charged.
So . . . letting the bike run at idle for extended periods will indeed drain a battery.  That is expected.

+1 
...but, if your battery is running down that fast, its not holding a charge well enough.  might be time for a new one.

you should get the following charge rates (12.4v at rest)
1,000 RPM --> 12.0 V --> -6.5 A
2,000 RPM --> 12.4 V --> 0.0 A
3,000 RPM --> 13.2 V --> 2.4 A
4,000 RPM --> 14.5 V --> 1.3 A
5,000 RPM --> 14.5 V --> 1.0 A
6,000 RPM --> 14.5 V --> 1.0 A
7,000 RPM --> 14.5 V --> 0.8 A
8,000 RPM --> 14.5 V --> 0.6 A

[2strokeTrush]

awesome thanks guys! well its been very bad weather in Baltimore lately and i have only put 78 miles on her so far, maybe 15 miles at a time. but when i ride for that long it will charge up a little yes.  What should i do to my fuse panel?

[flybox1]

..... but when i ride for that long it will charge up a little yes.  What should i do to my fuse panel?

Clean it.  Get a brass brush, or some steel wool and clean the fuse connectors.  gently pinch them closer so they hold the fuses tighter.  they're old, and can be brittle, so be careful.  look at the back of the fuse block, it often melts there.  if it is beyond good use, source a blade-style fuse block and replace the whole unit.

put your meter on the battery terminals and document your voltage at the RPM's listed below.  only then will you know if its charging properly.

[Kenzo1979]

If you're battery is running low after you charge it on the trickle charger, before you put it on the bike, you have a bad battery.  I just recently bought a brand new battery that did this because it had a bad cell.  If it's holding it's charge until you get it on the bike and run it (run it, not just idle), then yes, check you're connections.  You can tweak your regulator a little if it's not putting out the proper power, open it up and read your manual.

[Bodi]

All the regulator tweaking in the world won't make the 350-4 alternator charge the battery at idle: it just does not make enough power at low rpm to run the lights and ignition, the extra needed comes from the battery. "Tweaking" may cause overvoltage and "boil" your battery dry on a long highway run though! Adjusting the alternator is only advisable when all other problems are solved and the voltage setpoint proven to be out of spec.
There are aftermarket electronic regulators marketed promising charging at idle: unfortunately that defies the laws of physics, such claims are nonsense.