Bogus (?) Oil warning

[erolflyn@interaccess.com]

I'm STUMPED!

After a hard run, the oil warning light (and don't fergit the buzzer)
comes on in my '84 4ks at 2050RPM.  What the hell?

No matter what gear I'm in, outside temp, when the car is warm, at 
the approximate RPM, BZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ!.  If I let 
off or speed up, it turns off.   

It has happened with 10W-40, 5W-50, and 10W-30 oils.  I always use
Mobil-1.  The Oil pressure does not fluctuate when this is happening, 
so I don't think it's mechanical.  It also does not happen if
the car is in neutral and RPM's are 2050...

Does anyone have a clue???  Why would the oil pressure sender be wired
to the tach?

TIA,

Chris
'84 4ks
'70 Norton Commando
'87 Virago