Sunday, September 15, 2013

Ghost in the machine....


Or a gremlin on the wing. Either way, frustrating day.  All in the name of owning a classic bike, right?

The deal is the battery is loosing a charge when it's running.  Replaced the 37 year old regulator and rectifier with a 33 year old solid state unit (thanks Dan!).  Brand new battery.  Stator and field coil both test out fine.  Research tells me that these units rarely, if ever, go bad anyways.  Sometimes the wires or connections, but not the actual hardware.  When the bike is off, battery reads 12.6 volts.  Fire the bike up, drops down to 11.5 (ish).  Run it for a bit and it'll drop below 10 and the bike will die.  These bikes will NOT run without a battery, due to some kind of weird magnetic thing or something...

I have pulled every wire off, from the headlight back to the tail light and cleaned every connection and ground.  Stumped.

9 comments:

aaron said...

How did you test the stator? You can check voltage coming from it, directly from the stator leads while it's running to see if it's putting out, but every bad reg/rec I've seen allowed more voltage through, (too much), not less. If voltage drops when it runs I usually assume stator is bad or miswired.

tom said...

Good point, and it's what I'm starting to assume as well. I tested the stater by by an ohm tester on the leads. Three leads. 1,2 and 3. Check resistance from 1 to 2, 2 to 3 and 1 to 3. The manual says it should be a .2 ohms. I am at .4 ohms, that could be it? Did not test the stator while running, I should, just did not have a test for that...

Thanks for the tip! Now to see if I can get a stator in the next three days and instal it...

tom said...

Just found another stator test to try while bike is running, will give it a shot today and we'll see!

aaron said...

Honestly, I've never even done a resistance test, or checked the leads directly. The stator makes juice when the bike is running. If voltage at the battery goes down after it's started, I replace the stator. Maybe it's not the most thorough or by the book, but it's always been right so far.

tom said...

Just ran a couple different tests on the stator and field coil while the bike was running, again, it all tests fine. Wondering if there is something shitty going on in the rats nest wire loom. Anyone want a bike? Cheap.

Dennie said...

Can you run it without the charging system wired in? If you can isolate some variables it would be easier to trouble shoot.

tom said...

unfortunately, the bike will die when it falls below 10.5 volts. When I did the running stator tests this am, I unplugged the stator wires and the field coil wires and tested them individually. I'd run it with a flashlight for a headlight if I could.

aaron said...

That's good news! Wire is cheap. If you have voltage coming from the stator, worst case scenario is just scratch-wiring your charging circuit with some heavy duty fresh wire.

tom said...

well, replaced the stator and the field coil (both bench tested perfect) and it did jack shit. bullshit cockfucker. took it apart again and swapped the field coil for the original (also tested perfect) no difference. tapping out. I'm super pissed and even more frustrated. Will be on bicycle in NY, which is fine by me.
shit day. shit week. shit month. worst in recent memory.