Author Topic: Suddenly no electric power (Read 1874 times)

wingfree · « **on:** April 04, 2010, 05:13:57 PM »

Recent off frame restoration on my 1973 350F.

Finally after many glitches and mistakes, it fired up beautifully today.

Taking it out for a maiden run, I shifted to first gear. Immediately I heard a muffled pop and the bike died. No electric at all.

No dash lights, starter, etc. Fuse not blown. Battery full charge. Where do I begin?

Thanks for the input.

Leo

Gordon · « **Reply #1 on:** April 04, 2010, 05:15:50 PM »

Check the battery ground and the ignition switch plug.

scottly · « **Reply #2 on:** April 04, 2010, 05:19:32 PM »

Did the "pop" come from the exhaust??

bender01 · « **Reply #3 on:** April 04, 2010, 05:26:17 PM »

I had a fuse blow the other day. My fault touching with a screw driver, It didnt look blown.

wingfree · « **Reply #4 on:** April 04, 2010, 05:27:52 PM »

The pop was not exhaust, I have to question was I hearing things, It was very muffled. Immediately after putting bike in first gear (and not letting clutch out) bike died, all electric on bike dead. No fuse blown. Checked ground and ignition connections, all seems good.

Gordon · « **Reply #5 on:** April 04, 2010, 05:28:59 PM »

Quote from: wingfree on April 04, 2010, 05:27:52 PM

No fuse blown.

Did you try a new fuse just in case?

scottly · « **Reply #6 on:** April 04, 2010, 05:30:42 PM »

Do you have a voltmeter?

Duke McDukiedook · « **Reply #7 on:** April 04, 2010, 05:31:04 PM »

Quote from: Gordon on April 04, 2010, 05:28:59 PM

Quote from: wingfree on April 04, 2010, 05:27:52 PM
No fuse blown.

Did you try a new fuse just in case?

+1, check the fuse and terminals connected to it.

wingfree · « **Reply #8 on:** April 04, 2010, 05:34:56 PM »

Tried another fuse, still no go. Everything was working well until I shifted bike into first gear. Does this have anything to do with neutral switch, I cannot understand why everything is out. But I am very far from an electrical guru.

wingfree · « **Reply #9 on:** April 04, 2010, 05:37:50 PM »

I do have a voltmeter. I will need specific instructions on what to do to help locate the problem. Thank you.

scottly · « **Reply #10 on:** April 04, 2010, 05:41:16 PM »

Measure the volts across the battery + and -, for starters.

wingfree · « **Reply #11 on:** April 04, 2010, 05:43:36 PM »

13.01 volts across the battery.

scottly · « **Reply #12 on:** April 04, 2010, 05:46:55 PM »

With the ign sw on, measure volts from batt - to a bolt on the motor; dig the end of the probe in to make sure it's making good contact.

wingfree · « **Reply #13 on:** April 04, 2010, 05:50:10 PM »

13.02 volts with ign. on

scottly · « **Reply #14 on:** April 04, 2010, 05:53:05 PM »

If that is from batt negative to ground, your battery IS NOT GROUNDED.

750goes · « **Reply #15 on:** April 04, 2010, 05:55:14 PM »

+1 on that...check your "-" cable - make sure it has good contact with the battery and earth

wingfree · « **Reply #16 on:** April 04, 2010, 05:58:29 PM »

Scottly . If red probe from meter is on pos terminal of battery and black probe is on frame bolt reading is 13 volts. If red probe is on neg terminal of battery reading is zero

wingfree · « **Reply #17 on:** April 04, 2010, 06:01:19 PM »

Clarification last post when red probe is on neg terminal and black probe is grounded to frame there is a reading of zero volts

scottly · « **Reply #18 on:** April 04, 2010, 06:03:19 PM »

OK. That's good then. Next is to measure volts from ground to the fuse holder.

wingfree · « **Reply #19 on:** April 04, 2010, 06:06:26 PM »

Scottly I have 13 volts to fuse holder

scottly · « **Reply #20 on:** April 04, 2010, 06:12:10 PM »

Assuming you have volts on BOTH ends of the fuse, it goes from there to the ign sw. I don't know about 350s, but on 750s, there is a red wire from the fuse that goes to the sw, and it comes out of the sw on a black wire, when the sw is on.

wingfree · « **Reply #21 on:** April 04, 2010, 06:32:23 PM »

Scott, again thanks for your patience. When checking volts to fuse box and using battery terminal as ground I get the 12 or 13 volts. When using the frame as a ground I get several microvolts. When attaching the probe to the red wire from the ignition and use the battery as a ground connection I get microvolts. When I connect the probe to the black ign wire and ground using the battery I get microvolts.

scottly · « **Reply #22 on:** April 04, 2010, 06:37:52 PM »

Ok, I'm a bit confused: basically you should read the same volts whether using the batt neg or the frame ground for the black meter lead. I would disconnect the batt neg lead, at both ends, and inspect/clean.

wingfree · « **Reply #23 on:** April 04, 2010, 06:46:23 PM »

Scott I lied 12 volts to the fuse with grounding on the frame. Microvolts at the ignition switch with red or black ign and grounding to frame

scottly · « **Reply #24 on:** April 04, 2010, 06:53:50 PM »

I was suspecting that maybe you weren't getting a good connection to ground. Do yourself a favor and get some test leads with alligator clips to connect the meter to ground so once you make the connection, you don't have to worry about it.
If you have 12 volts going in, and leaving the fuse, but nothing (millivolts) at the red wire going to the ign sw, that must be where your problem is: the red wire from the fuse goes to the sw.

wingfree · « **Reply #25 on:** April 04, 2010, 06:58:51 PM »

Scott I am probably jumping ahead. The P O had trouble in the fuse area and spliced in wire. The input into the fuse box was good, but no current to the switch. I ran a wire from the fuse box to the ign, (bypassing the current wire from the fuse box to the ign). The bike powers up. Sounds like faulty wire from fuse box to switch. Am I correct? Thanks. Leo

scottly · « **Reply #26 on:** April 04, 2010, 07:00:35 PM »

Sounds 100% correct. And you are welcome!

750goes · « **Reply #27 on:** April 05, 2010, 12:01:52 AM »

I would be tracing that red wire from the fuse box to the ignition switch - it might be "live" and possibly shorting out against your frame - or against other wires. Check it along its length and either repair or replace it...then problem solved for a long time, or until the next gremlin raises its head..

wingfree · « **Reply #28 on:** April 05, 2010, 01:40:27 PM »

A little summary statement. The problem seemed to be the red wire as it was exiting the fuse box. I made a temporary repair and the bike fires up without question. Again many thanks for all the input. My mechanical skills are ok, but electrical skills have always been kind of scarey. The way to get through the fear is to just jump in and do it. With the guidance I received, it became a success story until the new gremlins appear!

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Author Topic: Suddenly no electric power (Read 1874 times)