I don't know what the best approach to take is but unless he personally saw you doing something naughty it seems like a pretty big jump to assume anyone who drops a bike is riding carelessly. I would certainly plead not guilty and explore your legal options. Without someone to dispute your defense of "I saw brake lights and even though I didn't have to slam on the brakes I panicked and did just that...gosh I don't know why," a conviction seems unlikely. You might even call the prosecutor right away and explain what happened and see if he would consider dropping the charges since you are a licensed motorcyclist and you think you just panicked. Tell him the fine money would be better invested in an advanced motorcycle safety class.
Personally, I think any officer who cites a motorcyclist for careless driving after dumping a bike but not causing any other property damage is a complete arsehole. Your pain and banged up bike is fine enough!
