Your bumper strip doesn't look that bad. I'd pressure wash the rest of the white strip off, remove it and treat it a few times with Yamaha silicone spray. Odds are it'll be satin black and shining like a new nickel.
Most people have never heard of the stuff but it's what I use on all my plastics and tires. I discovered it when I was racing out of a motorcycle shop. It's intended use is for winterizing watercrafts. You basically hose down the engine, plastics, electricals, etc. It wards off corrosion, rust, displaces moisture and introduces plasticizers back into the workpiece.
If you don't have a Yamaha shop close by, Amazon has it
https://amzn.to/2UZCJjD