I think the bike would go much, much better with the powervalves sorted properly. I wouldn't suggest removing the system altogether. The two sub valves aren't all that expensive. As for the 250 valves, I havent heard of them working and I strongly doubt they would fit.. I could be wrong though. Steer clear of used valves of at all possible.
Can you move the kips rod in and out by hand?
The governor has a nylon gear I'm quite sure, and all of its parts are cheap from Kawasaki also.