Jason,
when does it normally sputter? When idling? half throttle? full throttle? varying throttle? constant throttle?
I doubt it is water but maybe drain the fuelbowl as a precaution using the small brass screw on the rear LHS of the carby.
I’d say it could either be the TPS (throttle position sensor) or the jetting of the carby. The WR is known to sometimes sputter when held at constant throttle, such as riding on the road. You can disconnect the TPS connector at the carby and see if that makes a difference.
One thing to be aware of with the WR and cleaning it, is that water can get into the spark plug cavity and rust the outside of the plug. Once you finish washing the bike, lean it over on the RHS so any water can drain from the tiny hole in the head. Also, start and run the bike for a few minutes to evaporate any water around the plug. The rusty plug is really only an issue because when you remove it, rust scale may drop into the cylinder.
