I wanted to throw my two cents in on the keyster kits.
I ordered the same kit from ebay and read this thread and a few others about possible problems with the kit.
I was hesitant to use any of the kit, but I decided to go ahead and use selected parts from the kit for my rebuild.
I rebuilt all 4 carbs with the parts listed below from the keyster kit and everything seems to work fine.
From memory I used:
37.5 jet
152.5 jet
90 jet
o-ring and gasket under the jet block
mixture screws, o-ring, spring and washer
float bowl gasket
small thick o-ring under the slide covers
gasket for the coasting enrichers
I attempted to use the new brass looking kit screws that hold the jet block in place, but the first one I tightened up broke off. It is obvious the screw was inferior to the original screw.
I also tried to use a common sense approach to replacing the parts. I tried as good as I could to compare by sight, the size of the keyster jet with the original on the ones I replaced. I had a feeling my main issue was the rubber parts since I had previously tore the carbs down and cleaned them only using all the original parts including all the gaskets and o-rings during reassembly.
View my original post with a run down of the bikes problems initially.
http://www.vmaxforum.net/showthread.php?t=2430
Hope the additional Keyster information helps someone else out.
EDIT: Forgot to say that my bike is running fine with the above replaced keyster parts.
Thanks
Foz