With the FZ1 springs and 2.53mm slide ports I noticed a slight slid bounce on opening the throttle.
That tells me that the FZI spring rate is challenged by the 2.53 slide.
Hmmm...maybe a bit of preload might help. I tried a set of 12mm steel 2.5mm thick washers (that I had on hand) between the top of the spring & the carb cap to test the theory. It worked.
So, today I made a set of preload spacers from a set of Trackside (sourced from Cycle Gear) M12 aluminum 1.5mm thick drain plug washers. They are light, and with some drilling/filing fit the center post of the carb cap perfectly. Optimal thickness? Dunno, but the slide bounce is gone.
Gotta richen up the idle mixture a little bit though.
I also have a lead on some slide springs of the proper diameter that might have a rate less than OEM but more than FZ1.
