Stalling at idle and headlight gets brighter with any amount of throttle
 

Hi just bought my 2001 cbr600f4 a few days ago, after getting it I drove to get fuel and go to the supermarket when I got on the bike the battery was dead, after not being able to bump start it my friend came and we had no other choice than to jump start it using cables from his bike, went for a long drive to make sure, he suggested it might of gone dead from the immobiliser as it may of been sat in the showroom for a while, two days later my bike is now intermittently stalling at idle it’s fine for a few minutes then bang the revs drop and it stalls, With throttle it runs perfectly fine, but I’ve noticed any amount of throttle also makes the headlight brighten up, is this a battery issue or something worse? Hope someone can help and sorry for the long post. Cheers

The best way to find out if it's a battery or charging system issue is to put a voltmeter on the battery and see what your voltages are. My guess would be that it's a charging system issue.

That’s cool just didn’t want to spend £50 on a new battery when it could be something else I’ll try having a look