916 Where Does This Wire Connect To?

I'd say so. There is wear marks on it from a nut. See where it stretches to. Looks like an earth cable

 

pretty sure it earths on to the regulator back plate

 

Looks like it should go to the battery.
Steve

 

Looks like it is an earth connection shown with dotted lines on this drawing from the manual, fixed to the reg/rec plate as already suggested. There are three earths that connect directly to the battery terminal which look to be fitted correctly on yours, one goes to the back of the engine and two come from the main loom. Later series bikes with three phase systems have a different and much simpler arrangement down there

 

Thanks for that Denzil, as I have moved my reg/rec to the rear of the bike, I must have connected the earth to the battery myself rather than have it hanging loose.
Steve

 

Birdie, I think I would have put it onto the battery neg anyway, on my MY02 the regrec heat sink plate has no earth and is fixed to plastic tangs on the battery box so no earth connection and the reg rec does not look like it needs one. Has Exiges cables fitted and an additional heat sink too

 

That's filthy - sort it out man

 

Harry, the brown stains on the cases, spotting on the frame and damage to the belt cover and base of the battery box are what happened when the reg rec failed to high voltage resulting in a melted hole in the battery case, just the small amount of free acid from an AGM battery was liberated over a 100 miles or so of driving. Just as well it was not a normal battery otherwise there would be lots more damage. It looks a lot dirtier in the photo than it actually is but it will get cleaned (one day) when the engine gets fully stripped and the case repainted

 

Lucky escape - in reality it looks pretty good for 2002 vintage

 

Stop back pedaling ,man.

 

You're right - get it sorted it's a disgrace

 

and loop that Earth behind the frame while he's at it as the instructions show