This thread was very helpful for my troubleshooting so I wanted to be sure to let the next person know how I solved my fueling issues.
I had similar (progressively worsening in my case) issues on my 2011 FE570S. I was at the point of selling/parting out the bike. I spent many hours searching/reading posts of others having similar issues. These were my issues, hot running temps at all times (much worse when not moving in traffic), loss of power (hard to tell at first, just felt sluggish), stalling/"flame out" when starting after a traffic light for example, and eventually it would not run at all for more than 10 sec. but would run with starting fluid down the throttle body. What I did to troubleshoot, check for spray and proper pattern at the injector, check voltage at the TPS, advanced full CCW-~.750 helped slightly (and makes sense now as the injector was not flowing as it should have been), replaced TBS, replaced plug, cut 1/4" off of coil lead, new spark plug cap, removed 90% of the wiring harness from the bike (from rear to around the throttle body, beyond that didn’t seem necessary) and checked all wires for crush or other damage (at the subframe under the gas tank is a terrible pinch point. Not as bad of a project as I thought it would be, but not fun. Had to cut off all factory rubberized plastic sleeves and retape with high temp fabric automotive loom tape from Amazon, worked well), cleaned all connections at wiring harness, checked resistance at coil and stator (both were within spec). cleaned injector two ways; 9V battery method while on the bench with carb cleaner and the second with injector connected to bike hose (from radiator overflow) over injector nozzle and carb cleaner straw connected to hose forced cleaner backwards through the injector while cranking the bike. This helped but only for a 1 mile test ride than all symptoms returned. Finally, I purchased a new injector, changed TBS voltage to factory, and all seems resolved. I so far have taken it on a ~8 mile ride with not a single pop or stall. Like I remember it back in 2013 when I bought the bike. Hopefully this helps someone who faces the same problems. What seems tricky on these bikes as that all fueling issues, regardless of the cause, manifests itself with the same, or very similar symptoms. Looking back, this issue was not a switch flipping, but progressive as I stated earlier. On the last long rides, I spent many hours, in various locations, pulling the bike apart but learned a great deal about the bike. Moral of the story is to filter, filter, and filter your fuel and carry an extra injector. Hopefully this will help the next person that faces poor fueling issues.
