Motorcycle Repair: Charging system problem, charging system, volt meter

Question
Hi, ive been having a problem with my charging system, it started last fall just before storage, i just pulled it out of storage yesterday and put in a new battery thinking it was just a bad battery. well i rode around all day but mostly short in town driving, then a the end of the night it died at a stop light! i pulled it into a parking lot and push started it and got it back to my brother's house (3 hours from my home)
i hooked it up to a charger then checked it on a volt meter. it showed it was barely charging while at idle/possibly draining some. if i rev it up it seems to charge some (before starting the bike the charge was 12.89 and while revving it would go to around 13.25 ..so it wasn't fully charging but it was some).
today i drove the 3 hours home and it stayed charged since it was all full speed driving and the two gas stops i made it started up fine. i checked the battery charge when i got home and it was 13.05 so it only seems to drain if it sits at idle too long ..what do i need to do to fix this? its obviously something with the charging system i just dont know what, please help, thank you!

-Blake

Answer
Blake, motorcycles usually don't charge the battery at idle. The engine has to be reved up to 3-5000 rpm before it puts out enough current.  The battery voltage should be 13.5-14.5 volts if the battery is fully charged so 13.25 doesn't sound too far off.

Regards
Rich