I have used water down the carb for years. It cures "dieseling" problems due to a piece of carbon glowing and causing run-on (running after the ignition is turned off). I have done this many times with cars but have never used a spray bottle, just a cup with the engine running at around 3500 rpm. You have to be careful not to pour too much in because of the chance of hydraulic locking the engine (you have been warned). In a motorcycle with side drafts, a squirt bottle would work fine.
Another piece of "old tech". If you need to find a stubborn exhaust leak, get the engine up to operating temperature and pour a little brake fluid down the carb. It will smoke like crazy and you can see the leak. It is also a pretty good prank. Beware though, it smells pretty bad.
Dan
