Motorcycle Repair: honda charge, honda cbx, alternator

Question
hello wonder if you can shed some light on this problem bike starts up with 13.5 until it seems to get warm then goes down between 10 and 11 thought it was fault in lights did check but found nothing wrong renewed battery ,regulator /recitifier/and alternator still follows the same pattern any ideas because i havnt now thanks martin

Answer
I'm hoping this is about a Honda CBX.  It sounds to me like the alternator is not spinning as well after warmup.  Could be the oil you are using (hope you're using fresh GTX 10/40) or the alrernator drive spring (are the two washers in place behind the driving plate) or the alternator clutch itself.  Let me know,  Jan