Yes, I know what the TPS does - it gives the reference voltage for the throttle opening to the ECM to use in the fueling & timing maps; it is critical that the map has the correct value for the 'zero' starting point, which is calibrated for the idle speed of 1300rpm with the throttles closed;
which is why I don't understand what you are saying by
You set the idle speed first and then calibrate the TPS to 'zero' - or at least the voltage which translates to 'closed' in the map table.
Saying the factory is 'set to 2500-3000' is completely backwards - if it was not correctly calibrated, you
could say that the TPS voltage (or the display reference) is either low or high at 1300, but to say it's 'zero'd' at 2500-3000 is misleading.
(I use the term 'zero'd' only metaphorically as far as the graphical display is concerned - in real terms is actually about 1.1V)
Or maybe you simply mean that the display only 'zero's' (the middle bar on the graphic display) when the rpm is increased to 2500-3000? That's still an odd way of describing that miscalibration - sorry, not trying to be picky.
I'd also be
really surprised if indeed bikes are that far off from the factory.
That's also why the OP's original post saying
makes no sense - you don't adjust the TPS
to 1450 (or to any value of rpm) - you adjust it
AT 1300.
One note to anyone adjusting this - there is a slight delay in the display registering any change as you adjust the TPS position, so
gently nudge & wait for reaction before you go too far.