My battery went flat the other day so I recharged it on a trickle charge for 24 hours, the bike started straight away, but when I took her on the road I put the heated grips on and when waiting at light on tick over the warning light on the grips came on due to lack of power, then I turned on the headlights and when I dropped the throttle to change gear the electronic rev counter dropped down to zero and only picks up again when the change is done and the revs are going back on. I think it's the reg/rec but my knowledge of the workings on bikes is petrol goes in the hole at the top and that's about it.                                                                                                                                                                             

Sounds like it is the reg/rec. Do you have a multimeter. You can use that to determine if it is a correct diagnostic. If you need to know how, PM me and i will let you know.                                                                                                                                                                              

it may just be corroded wire connectors, or a wire to the rec /reg has corroded thru. Check yer wires before you spend out on a new unit. There was so much salt on the roads last winter it was unreal. I'm off work till friday, text me if you want a hand.

hi you,ll find with most charging problems it either the windings or as stated regulator rectifier, to test windings there is 3 yellow or 3 white wire, depending on bike voltage can be from 50volts ac to 70volts ac or even on a ducati 110volts ac  test ac volts by Y1 to Y2=70 volts  Y1 to Y3 =70 volts Y1 to Y3=70 volts , if either y1 or y2 or y3 has a reading to neutral ( chassie) then its faulty, or no reading at all,
  can explain how to test regulator, but thats a long long story, if you need any more info refer to www.henry-volt.co.uk