Hi everyone,

I am using a stock 2005 CBR1000 fuel pump in my fuel tank which then runs through a new 6mm ID fuel line and new filter to the 1000 engine but am having an odd issue where if the engine is idling and I give it a quick stab to 6000rpm it runs rough on its return to idle and then misfires if trying to accelerate again. If I let the idle settle down I can repeat the above, it seems like it is having a fuel supply issue (it also runs like crap if I try driving it as well like it is almost out of fuel). Fuel pressure checks out ok as does fuel flow according to the CBR1000 workshop manual.

What size fuel line have others used and is the factory pump ok for a BEC scenario?

Based on age I suppose you are running Throttle bodies, if so, most likely a overrun fueling map problem.
6 mm seems OK as thats what my mustang has as standard and good for 215 HP. (maybe even slightly smaller)
HTH.