starting issue//starter solenoid

[dyelawn]

My 1982 CB750C usually starts up no problem if it's in constant use, but sometimes has problems after sitting for a few days or more.  I came back from a camping trip the other day (bike sat for 4 days) and it had trouble starting.  This time though (hasn't happened before), I didn't hear the usual whining sound from the starter, like it was trying to turn the engine over, I just got a clicking sound from the starter solenoid.  I tried the starter button a few more times and then the whole bike went dead.  No lights, no power, no nothing.  

Suspecting a connection issue, I've been checking wires and fuses over the last day.  The main 30A fuse is good and in tact.  The battery is fully charged and is holding 12.4 V.  After taking out the fuse, readjusting the battery leads (in reality, I really didn't do anything, just unscrewed stuff and screwed it back in), I got power to the bike again (dash and head lights).  Still heard that clicking sound at the starter solenoid, though, and the starter engine wouldn't engage.  

I checked the thick red wire that goes from the +battery terminal to the starter solenoid by unscrewing it from the SS and running a meter between the end of that red wire that usually screws into the SS and a ground on the bike.  I got 12.4 V running through that red wire.  Does this mean it's good and not shorted or otherwise compromised?

Much to my surprise, I rescrewed everything and tried starting the bike one more time - fired right up this time.  At this point I'm a happy camper but still suspect something is up.  Could all this really be caused by a bad connection between the SS and the battery?  

Some other relevant background info:  I've been having starting/electrical/charging issues with this bike for a little while now.  One time it died on me while I was riding and wouldn't start, then started randomly about 3 days later.  Haven't had major problems since then, but as I mentioned before, usually if it sits for more than 3 or 4 days it has a really hard time starting - usually have to push start several times before the starter works consistently.  I suspect I have larger issues here.  Been working through a tutorial for diagnosing charging system issues but haven't found anything wrong yet.  Could all these problems really just be the result of a few bad connections?

First post.  Any help or insight would be greatly appreciated.

[Re-run]

Do you know how old the battery is? 12.4 is slightly low as it should be about 12.6-12.7, each cell is about 2.1 volts.

Maybe give it a full charge and take to a shop and have them load test it. This will at least rule out the battery.

Otherwise, your suspicions are probably accurate. It is most likely a connection somewhere, my guess is either a ground or connector unit.

[dyelawn]

Thanks.  FYI, it was the battery.  Even the load test at my buddy's shop seemed OK.  After checking all the connections I decided fuck it and went and got a new battery.  Has started every time since.  

[TOOLS1]

"Could all this really be caused by a bad connection between the SS and the battery? "
YES!
TOOLS

[LukeM]

Glad you figured it out.  The batteries for these bikes don't last very long.  While you're in diagnostic mode, check the voltage at the battery with the engine RPM around 3k.  You should have between 13 and 15 volts at the battery terminals.  If it's below or above these values, your charging system may need some attention.  An easy check is the 3 yellow wires from the alternator to the regulator/rectifier.  The Molex type connector can build up a bit of corrosion, to the point where the connectors will spark and burn the plastic.  You can solder the wires together, but this will make swapping the R/R out a bit of a pain.  It's also possible to get a replacement connecter and terminals.  

Now get out there and ride, while there's still some good weather. :-)
Luke M