Got myself a clapped out 1400

[Eric GSX1400K3]

Should clean up nice i reckon.

Check the in tank fuel filter and teabag too

[Mick_J]

Welcome to the forum Willow. 

[Hooli]

I've just remembered the other thing I was going to suggest Willow.

Check or just replace the vacuum pipes off the throttle bodies to the MAP sensor & PAIRS valve (if still fitted). They split with age & cause the symptoms you're getting. It's 3.2mm ID hose so a common fitment & any car spares place will carry it, just don't snap the T-pieces or you'll need to replace those too.