I've fitted the Domino throttle to a couple of my bikes with no problems. They are a good quality kit and perform well, but to be honest have nothing else to compare them with. Also maybe being a bit naughty as using the single cable version ie relying on the spring on the carb for throttle return, but it works well and absolutely no problems either on road or track.
I found that I needed a slightly longer throttle cable to cut to the length required, as the standard cable for the ZXR is just a smidgeon too short. Got a cable from a ZX6R lying around and used that as a donor. I snipped the nipple from it, removed the cable from the shroud and re-inserted it into the ZXR4 shroud just to keep things as standard as possible. Wrap some insulating tape around the end of the cable before you cut the nipple to avoid loose strands..keeps things smooth for drifting it back thru the shroud. From there it was a case of trial and error to find the perfect position for the kit nipple and still leave adjustment. Whole thing takes about an hour so not a big job. Watch out as there are two settings for the throttle, the cam is reversible depending on what you want.
I got a few units from Allens Performance a couple of months ago. Cost then for the kit was £21.00 + VAT. Domino Part Number is 1469.03 (think its for an Aprilia?). Much cheaper than some of the race suppliers!
Web:
www.allensperformance.co.uk
E-mail:
steve@allensperformance.co.uk