I have an 02 f4i and when i first bought it there was a whole slew of battery problems. It would die after one startup so tried charging the battery and the same thing kept happening. Ended up getting a new battery and it was all fine till it got a little colder then warmed back up and now i notice that when the bike is idleing the light even on high beam is very very low but when im running even at just 2 or 3 rpms its gets brighter like its supposed to but this is a big jump up. Anyway is this just normal or is there something wrong if there is something wrong what can i do to fix it?

 

2 or 3 rpms? are you saying 2000-3000 rpms?
make sure your bike idles at around 1500 rpms at a stop

Using a voltage meter, check the voltage at the battery with the engine & ignition off (reading should be above 11.8 volts and below 13.2 volts)

some cause might be the bulb or alternator/generator
Headlights are probably the highest-draw item on your motorcycle. It might be the bulb usage

 

yeah thats what i meant. and yes it idles at around 1500 rpms at a stop. still need to check the voltage .

 

Here we go again. Some don't agree with me, but if you look up the info in your shop manual... the generators and rectifiers on our bikes don't recharge the battery at idle. The charging voltage and test voltage to see if your gen/rec are working will be somewhere around 4000 to 5000. Also... the high beam is only meant to be used while you're moving, not at idle. Break out the multi meter and run you bike up to 4-5000 rpm and see what you're voltage is.