problems starting
 

Hows it going, everybody? Haven't been on in awhile, probably close to two years when I first bought my f4i and was having problems.

I recently (~month) was medically discharged from the Marine Corps and came home. Roughly a week after getting here I went out to fire up my bike but the battery was dead. I jumped it using my battery chargers jump mode and it started right up, once I pulled the clip it died, so I left it running on the charger for about a half hour hoping maybe it would hold a little charge, but notta. So I left the battery on charge over night, but it wouldn't hold a charge, I think it is shot. The other day before my brother left for drill we swapped the battery out of his cbr into mine, the instrument panel turns on, gauge sweep works, etc. All seems good but the fuel pump won't prime, I disconnected/reconnected the wiring harness, reset the ecu, and checked all my fuses. I just pulled all the fairings off to get a better look later, haven't checked the kill switch yet. My headlights are working fine as well, I am not real sure what the issue is. The FI light is giving a code, one long 5 short, a friend told me that has something to do with a bad fuel injector but that can't be. A year and a half ago I had the bike completely gone through and everything replaced, today it only has 5k miles on that rebuild, so wth? I need help, I am missing all of the good weather and I really dont want to take it in to a shop!

Does it crank over with the good battery in?

Yes, it does crank, but the fuel pump doesn't prime so it doesn't do much more than that.

Headlight on?

Headlight does come on when the ignition is turned on, the high beam works as normal with the switch.

Code 15 is for the #4 injector. That won't cause it not to start.

Check the kill switch, all the harness connectors including the ecu, all grounds, and the BAS. Some had the BAS in the headlight, while some had it separate. The BAS will kill the pump, that's what it does. To bypass it, jump the outer wires of the harness together.

Other than that, how are you with pin testing for voltage? Need to see if there is power at the relay and pump.

after tearing my bike down for paint and reassembling my pump wouldnt prime and it was the relay in the rear fairing, there are 2 relays on the exhaust side and i believe it was the one closest to the tail light, i ran a jump wire from mine to a good ground for a temporary fix and then replaced it and i havent had any problems since then, may not be your problem but hey its something to check lol

Thats your first problem, your not charging. Once its running it doesn't matter how dead or alive the battery is as long as its there.