battery
 

hi everyone just a quick question ,a freind of me has an f2 and the battery died so he went and bought a new one but didnt take the old one with him so he got the wrong one about half the size.
the bike ran ok for about 2 weeks then the batt died,i have checked stator and regulator and everything ok.
so my question is does the type of batt make a difference.
thanks guys.