Those plugs are tricky to remove. You have to take a tiny little pick and pry the retainer wire out at each end of the plug to get the plug off over it's retainer shoulder.
Sorry, I omitted telling you that. Now that you have the injectors out......after you have made some attempt at cleaning them, you can reinsert them in the upper fuel rail & point them out over the edge of the valve cover at a sheet of brown carboard about 8 - 10 inches away & cycle the starter.......you should get 4 nice even round damp spots on the cardboard.
CAUTION: Extreme fire danger when doing this.....make sure you don't have a disconnected spark plug wire or other ignition source hanging nearby. A fire extinguisher is recommended also.
OBTW. Each injector has a tiny little strainer screen kind of pressed down into the inlet port....very difficult to see, even when you know it's there.
You may have to find someone with an ultrasonic cleaner to clear them. I was fortunate on mine......even though I had year of deteriorated gasoline & gooey rubber all over inside the tank, Once I got the new tank & pump, the bike finally stuttered to life after about 15 mnutes of intermittent cranking. I did have a new battery in it also. I never did have to clean the injectors......I did run 1 can of Chevron techron through the first complete tank of fuel.....no worries since.
"Regards, Ibj...
PS: I'll be offline for 10 days starting tonight.....headed for the BMW rally in Salem, OR