So i have a new problem, please bear with me as i am a noob and dont know these bikes too well, problem started this morning, rode my bike to work, came outside this mornmorning to leave and the battery did not have enough amps to crank the engine, so i pop started it(which by the way is not easy as a rice rocket) started and drove home(which is about 15 mins) with no issues, now that tells me the alternator is still good(if im wrong please tell me) got home and check what i know to check, as far as i can tell, charged battery, started up, had a multimeter on battery while giving it gas no change in voltage, so this means the battery is not being charged, so there must be a wire loose correct or corroded, or broken? The problem is, i dont know where to look, please help im not too smart with this stuff and have no more money to dump into it at the moment, if you could supply pictures that would be great(my bike is a 1991 sportster 1200cc) thanks guys

 

Do you have a Service Manual as it has a wealth of info for testing components.
Are the leads to the battery solid and clean?
What voltage are you getting with the bike not running? What voltage once bike is going? Crank it to 2000+ rpm, what voltage then?
Take off neg cable and put a meter on the cable and neg battery post. You should not be getting more than 3.0 mA if you are then something is draining the battery. Of course everything is off when you test it. If it's draining you got to check all connections.
That should be a start.
Somebody else will pipe in.

 

A connection issue will not create a draw on the battery.Have the battery tested.Reason?A bad battery will not let the alternator function properly.Alternators don't charge a battery,they maintain a state of charge.I have an 06 and thought the alarm was draining the battery,since new I might add.Well one day the battery would not even charge.Bought a new battery on Ebay and now it's never dead when I go to ride.The battery was $56 to my door.However a draw test should be done as outlined above.If the amps are too high pull fuses to find the affected circuit and go from there.More than one item is on each circuit so you may need to unplug things on each sub circuit.The manual will come in handy for that.

 

With the key off, check the battery voltage. It it reads bellow 12 volts the battery will need to be replaced. To complete any further testing you need a health, fully charged battery.

 

thinking bad battery , if they bike had just started there would still be some voltage showing on just the battery if the charging system wasn't working , if the battery is bad it won't show any voltage and will not allow the bike to charge it. also if the bike was running there was voltage coming from somewhere no matter what the multimeter said. short answer have the battery checked imo

 

Its sounding more and more like the battery not holding a proper charge. If he at least had it sit overnight or the last time he rode it, it had enuf CCA to start the bike which it then maintained itself while the bike was running. Bcuz in a short time he went to start it again, the ole battery cells didnt have enuf time to rejuvenate itself again and provide enuf CCA but I bet if he left it all day prolly enuf to crank it and start it again.
I had a car battery act like this. I couldn't get my head around that if I let it sit overnight it would start but after a short run and turning it off for a short time it wouldn't start. But the battery read good but it basically lost it's cranking amps power.

 

Thanks for all the responses.

So am i correct to think the charging system is ok, because of the fact the bike will run after intitial start?
if the charging system was not working properly the bike wouldnt stay running correct?

If the battery was too dead to hold a charge, when i rev up to 2000 rpms, would the volts on the multimeter still go up or would that not move? Thanks

 

What are your readings?

 

On the voltmeter, after battery is charged it will read 12volts, when i rev up to 2000 rpms it doesn't change, it dont go up 13 or 14 volts, then the battery voltage gets lower

Now a dead cell in a battery can cause all this correct?, what i mean is, even if the charging system is working properly and there is a dead cell, the voltage will not go up when giving gas, or am i wrong?

 

If it's reading 12.0 volts after charged I think its shot. My understanding it has to be over 12.5 volts.
If the charging system is gOod and the battery does not improve it's a goner I think.
Your battery is prolly maintenance free so you can't top off a dry cell.
I might be wrong but I think the battery is shot.