intermitent exup fault,any ideas?

[Falcon 269]

Funny how Yamaha patented the EXUP and as soon as the 10-year patent protection expired, all the other manufacturers fitted similar systems to their motors, eh?

And how about the latest WSB round problems encountered by Aprilia's Eugene Laverty with his exhaust valve?

Jetting/mapping and air intake corrections are two thirds of the equation but altering those won't counter less than optimum exhaust performance.

Still, you're sure you don't need it so there's no point in trying to persuade you otherwise.