Rough running in the rain fix
Here is a tip I got from a veteran wrench who owns a newish Speedmaster. The engine was coughing, farting and stalling in wet weather. The guy traced it to the fuel overflow/breather tube that descends from under the tank and drains low down on the right side. The setup is the same on my 2011 Bonneville SE. Anyway, the front tire was throwing up water into the bottom end of the tube, causing an obstruction in the line and a vacuum in the fuel tank that eventually impeded fuel delivery and led to coughing and farting. The guy corrected it by trimming the tube at an angle, with the opening toward the back. Probably it is best done preemptively.
It occurs to me that this could be an issue on almost any bike with the breather tube thus situated, as it usually is.