Topic: cb350F blowing fuse when turning on ignition switch

[stinedvd]

Alright, I'm out of ideas and need the help of the forum experts.  I have a 73 cb350f.  When I turn my ignition key on the main (only) fuse blows immediately and there is a slight click.  I can't tell if it is the click of the fuse blowing or something else.  With the battery out and an ohm meter across the positive and negative battery cables on the bike, I get 2.2 ohms.  I call that a short. I have no idea what the problem is.  I have tried disconnecting several items and try to see what the problem is but not really finding anything at fault.  Can anyone with a cb350f tell me what I should be reading with any ohm meter with everything connected except the battery?  If I disconnect the Alternator wire harness it goes to ~110 ohms, but that also disconnects the oil pressure switch and the neutral safety switch. Which makes sense to me because with both of those items connected you are essentially reading across the indicator lamp filaments, which is about 5.5 ohms outside of a circuit.

I tried testing the regulator and rectifier as stated in my manual and they all seem to have sane readings.

I put clubman handle bars on and thought maybe I had a short in the wiring, but disconnecting all the wires in the headlight bucket for the bars makes no difference.

Any help or insight would be terrific!

Thanks in advance.

Dave

I really want to get this baby purring again, but this is just driving me nuts.

[stinedvd]

Just wanted to let everyone know I finally found the short and is fixed. It was in the handlebars in the feed wire to the turn signal flasher. How I found it was to buy a 15A breaker and put it in place of the fuse so I could systematically disconnect connectors on the bike to narrow down where that darn short was.  I hope the technique comes in handy for someone else who is having a hard time finding a short in the harness.

[lucky]

That "click" you hear IS the fuse blowing.
A direct short is not 2.2 ohms . It would be infinity.

IF you put multimeter set to the ohms scale, across the battery posts
It would try to short your meter.
The meter is protected but the multimeter has a fuse in it too. Better check the fuse in your multimeter now.


IF you put the multimeter (set to 12VDC),across the battery posts it should read 13.2-13.8 volts if fully charged. Each cell is 2.3-2.7 volts and that is over 12volts. But we still call it a 12 Volt battery.


I guess a 13 volt battery would be bad luck?

[stinedvd]

Thanks for the reply Lucky.  In my mind 2.2 ohms isn't very much resistance and is almost a short.  But yes you are right, technically speaking.  Since I found the issue the was in the feed to the turn signals the turn signal relay was also clicking like crazy when I connected the breaker to troubleshoot the problem.  I was checking all resistance with no power applied the battery was removed until I thought I had it fixed and then would connect the power with the ohm meter disconnected so no worries about the fuse in the DMM.  I know not to test resistance in a live circuit.