Electrical Problems?

I just bought an '82 750 Seca. Sometimes it will have enough voltage to start other times it will not. The first few times I started it it was fine then the other day it didn't. Then it started again a few hours later. It's a good battery (so the guys at advance auto parts told me.) Three days later, I got it registered and took it for a spin around town (started up fine more than once because I killed it twice on an uphill stop because I just learned how to ride). It sat for 6 hours during the day and then didn't start again this afternoon. The dash lights were really dim. It will probably start again later as has been the pattern. All fuses are good. Battery is not corroded etc. I can't figure this out with my basic knowledge of how the electrical system works. Please advise. Thanks!

 

Have you cleaned the battery connections on both ends of the battery cables(positive and negative). ? Battery to solenoid, solenoid to starter and battery to frame/engine ground.
A failing starter motor could also cause a similar problem.

 

I've only cleaned it at the battery. I don't think its the starter motor because when it does have power it starts up perfectly.

 

Bad starter brushes will cause a start or no start situation.

 

Now you need to realize I'm not a trained machanic but have been around engines for a little while lol - the next time it will not turn over you could lightly tap the housing ( LIGHTLY ) on the case where the starter brushes are located - if the brushes are borderline / or a buildup of worn brush material are preventing them from springing in properly the tapping may just move them enough to get them to work - intermittent electrical problems are a pain in #$%# - good luck