Just got done cleaning the carbs out. The process of getting them off the bike was reasonably straightforward with the Haynes manual apart from the damned throttle cables. In the end I had to take the carbs half off the bike to get some access and then wiggle everything around to be able to disconnect them. I'm not looking forward to re-connecting them and I don't think all the twisting and pinching with pliers is too good for the cables but needs must.
Cleaning them was quite enjoyable. A few years back I took the carb apart on my CG125 (my first bike!) and it went back together no problem, but that was a single cylinder slide carb (I think) whereas the Fazer has 4 times the carbs and each is more complicated. The first one was quite clean really and I felt I might be wasting my time. Then I got to the second one and it was in definite need of some TLC. Pilot jet was indeed blocked. I treated myself to an air compressor and with a bit of carb cleaner whatever was blocking it is now banished to the floor of my garage, never to be swept up. As I progressed across the carbs another one had a blockage in one of the holes on the side of the main jet as well and also a blockage in one of the needle valve seats. Does a blocked needle valve seat cause overflowing carbs whilst the engine is running?
As for the rest with such blocked carbs I'm thinking maybe the tank is rusty on the inside, anybody heard of this being a problem? I think I'll fill a few glass bottles from the tap on the tank whilst it's off the bike and see if I can see any particles.
I also bought myself a carb balancing tool so I'm gonna have a look at checking the valve clearances, then put the bike back together and balance those carbs. Bike should be ready just in time for winter!