That sounds totally weird to me.
I'm more curious as to how something on either side of that equation got a positive charge - based on what you said it seems that either the shifter or the frame is positive and it's grounding into the other one. Of course, neither should be carrying a positive charge.
Does this happen when the bike is on/off? With the key in? With the kill switch on/off?
One way or the other, it sounds like you've got some naked wire touching something it shouldn't - like the frame or the engine.
Time to get out the flashlight and the trusty $3 Harbor Freight multimeter. I'd start by giving the whole wiring harness a good inch by inch eyeball and see if you can spot any exposed wire. One thing you might want to look for is that your engine might not be grounded? There's a ground wire behind the coolant reservoir on the right side of the bike.
MF Battery, Iridium Plugs, RR relocated, Voltmeter, 170/80/15 Kenda Kruz rear tire, DIY Samsonite hard bags, DIY shaved seat with Beaded seat pad ('cause that's how I roll) and the dreaded STATOR CHANGE.
Shining Black Bess '86 VN750, retired for parts after a fried stator and being knocked (kee-runch) in her parking spot.