Draining the carbs
From Ninja250Wiki
So, you might ask "Why would you want to drain the carb float bowls?" It's a good idea to drain the carbs for long term storage (winterizing). You should also drain them any time you think your next ride might be several weeks in the future. It's also the first step if you're going to be removing the carbs for cleaning, but you'd also need to drain them as part of troubleshooting a non-running or poorly running bike... typically a rather sudden change in running condition, usually right after filling up with gas. This is normally water in the gas, which sinks to the lowest spot possible ~ the carbs.
