No power!

First topic message reminder :

My bike was out in the elements and unused for three weeks whilst I was stuck in the UK with covid ( I had not planned being away that long!).  On my return I found the battery had died so replaced it and all seemed Ok, the bike starts and idles - but will not rev past idle.  I have drained the tank and changed the fuel thinking it may be contaminated - but no joy.  It was fine when I left it!  It will idle happily indefinitely - but as soon as the throttle is twisted it dies.  Any ideas?

Have always taken carbs off bike and kept throttle cables attached to them!
Easier to reattach cables to the twist grip than trying to attach and adjust between carbs while  on the bike.

Its probably a good idea to remove tank and drain it. take out petcock and flush the tank a number of times.
You can pick up a fair bit of crude from servos over the years.

Maybe an inline fuel filter between the tank and the carbs??

Yeah, the tank was flushed during its last service and an inline filter added so the basics had already been covered.