I've been experimenting with different spring rates & slide configurations, with the theory that running pod filters (in my case Uni UP4229's) reduces the vacuum demand & therefore lighter springs can be run.
Here are some preliminary thoughts:
OEM springs are too heavy & make for lazy throttle opening.
The Kawasaki GPZ springs are too light; the slides open too fast.
Stretched GPZ springs work better than stock GPZ springs, but are not optimal.
Yamaha FZ1 springs (made for a 37mm Mikuni) work better than stretched GPZ springs.
OEM springs clipped 9mm improve the low end, but the spring rate is too high above 5k.
The OEM slide opening (approx. 2.5mm) is sufficient with the FZ1 springs. Drilling the opening out to 2.8mm is too much with the FZ1 springs.
Still experimenting, so stay tuned...
