Decided to wash my vfr 800 fix and did so with a hose on fine mist setting all round. Then sprayed with MucOff before rinsing again. Made sure it was fully dry and took out about four hours later.
Only got about a mile down road, filtering through traffic, when I started to hear a scraping, grinding noise at low speed with the clutch in. Once I am sure I heard it at a stop!
I stopped and had a good look round, started it and revved but didn't hear anything.
I got a few miles further on and heard it again, so I stopped again but no luck.
I decided to abandon my destination (50 more miles away) just to be on the safe side and took a long way home. Didn't hear the noise again.
I would think that it could be just a bit of "flash" rust on the surface of your brake discs, dragging against the brake pads. A common occurrence on disc braked vehicles after being parked for a little while under the rain or after being washed...... As in cars, it usually goes away after a few applications of the brakes
But then don't our VFRs have stainless steel Brake discs? I can't quite remember if I ever saw flash rust on my discs, but then some lower grades of stainless do exhibit some corrosion......
What Beck said, and a good wash can loosen some grit around the calipers, possibly causing the pads to not retract smoothly. Don't know the mileage or age of your brake piston seals and pads, but if the sides of the pistons get dirty and/or corroded enough they can hang up and cause any runout in your discs to hit the pads a few times causing an intermittent scraping. One possible cause. I don't have any experience with "MucOff", but sometimes real strong soaps can loosen up dirt that was holding things in place, and muc things up. I use a shoestring around the brake pistons to polish any dirt off so it doesn't scratch up the pistons and seals.
If it only happens when you apply the brakes, that might be it. Obviously, could be other things. Chain/sprocket, something hitting a tire, etc. Maybe there is a bug in your helmet, chewing on the liner near your ear... :unsure: