but if your hung on the idea of the air striker you can either just disconnect the TPS but this will mean that you will have full throttle powervalve openings and ignition timing ALL THE TIME.
Or simply install a TPS from an RGV250 that isnt connected to the carb.. eg: throttle cable goes to TPS and then another cable goes to the carb.
but If I was you, just buy a $50-100 PWK39 from the RM, thats what I use on my CR250 road racer.