I like this one I spotted recently on the Idaho Montana border over Thompson Pass. I actually turned around to come back and take a picture of it. The arrows showing that you must? should? will? lean are classic.
The sign should just read... Excellent Motorcycle Road Next 21 Miles
There are signs on the Putty Road that say "Motorcycle Danger Area Next 15 kms." I reckon the thing to do is go flat out so you minimise the time you may be exposed to danger??