Motorcycle Repair: 1980 cb750 c, oil pressure switch, low oil pressure

Question
Two questions.
1. After the engine warms up the oil light comes on at idle speed (1000-1100 rpm). When the rpm is increased to 1500+ the oil light goes out. Any recommendations to correct?

2. The spark amplifiers are melting out the black tar like material that seals them. was told that this is normal. is this correct?

Answer
I've never seen the insulation melt out of a coil.  If you are talking about a little material around the high tension lead, yes.  But if it's melting out and dripping,no.  What weight oil are you running?  I'd replace the oil pressure switch first and check it with a pressure gage.  Someone may have replaced it with a higher setting switch.  It's not normal to have low oil pressure to the point the light comes on at idle.  It could be a plugged oil filter, a bad switch, worn oil pump or very worn bearings.  

Regards
Rich