When the CEL comes on for a few seconds and then goes out, that indicates that you have a stored historical diagnostic code. The issue that set that code is no longer active, and if you just leave everything as is it will eventually clear itself after a certain number of engine on/engine off cycles. I personally prefer to check the code and clear it myself, so I'll be aware of possible intermittent issues. Often you will get codes that resolve themselves almost immediately when you have a bike tuned or have other work performed. If you clear the code (write down the code or codes first for your records), and they return, then you need to have some diagnostics run to determine why.
Jerry