TBH I dont know. I personally hav'nt had any problems with the early TPS other that water ingress that has occoured due to spindle wear. The later TPS on this project is all new to me so we will see.
Will get some pics of a s4rs ones fitted to a 888. You can prob fit 999 ones with some mods. Your engine could well do with the bigger opening. 54mm I think
Originally 748R. I discovered that the inlet manifolds for the heads on my RS engine had an in-built O ring seal that had the same diameter and the body taper was the same as the 748R throttle body, so all I had to do was to reduce the length of the 748 bodies to fit! Easy. They fit perfectly! Obviously the throat of the inlets did'nt match the TBs so I machined the bodies out to suit and blue printed them to the inlets.
Its all about the velocity of the air through the venturi which is after the TB. I have 54mm throttle bodies and if I were to go larger it would mean that fuel air mixture would suffer especially at lower rpm. My cylinder heads are customer supplied WSBK heads but still the inlet throat is only 46mm so 54mm TB's are ideal for a non Foggy rider like me.
