Motorcycle Repair: starting the harley..., 12 volt battery, harley davidson sportster


Question
I have a 1985 harley davidson sportster XL, but heres where it gets interesting for me, someone told me its not a sportster, an it sounds more like a big twin, so im not sure what im up against now, but here is my problem: ive been riding it for several weeks now, and it had a charging problem, i would be limited to starting it, and then after so much starting, the battery would not have enough power to start, so i would give it a jump, then it goes great, i would get home and put the charger on it all night, and by morning its ready to go like nothings wrong with it. Now, the other day it did not start, turned the key on all the lights were on, and it would give me a buzzing sound, at first i thought it was the starter, we checked the starter, its a Hitachi (according to manuel, its a 1974-76 model). My first question: according to my shop book, any starter model under 1981 can Not be tested to see if it is good, or bad?

I was unsure of my question, now, my battery is new and running at 13.84v, what a 12 volt battery should be running at (unless im wrong). i know its not my battery, so then i thought it might be my starter solenoid, so i replaced that, Not knowing if that was the problem or not, atfer that it still gave the buzzing sound. So we listen to where the sound might be coming from, and it came from my starter relay, so i replaced that, still the harley did not start. Now im looking at my breakers and im not sure if they are my problems now, then i thought maybe my ignition key, so i changed that, still nothing... What can i do to fix this problem?

Answer
First, check your battery cables at both ends. A weak ground will cause your problem. If they are ok, Then i would pull the starter. Check the brushes in it as well as the armature. The armature can be tested.
It might be weak and need rebuild or replaced.
Good luck and happy riding
Mike