Hi Bill,
You definitely have a very nice looking bike, and did an excellent job refurbishing the parts. It seems just about anything from Japan has some level of corrosion on it.
I also have a 1997 CB50V that I recently picked up, and although I havent ridden it much I noticed I keep topping out at about 50mph.
I instantly suspected the carb being the issue as the bike has a Takegawa 89cc kit and its easy to oversize the carb/jetting expecting to get a ton of power. (right now i can take it to redline in first gears but in higher gear cant go over 8K rpm and after a couple of passes it seems to loose power almost as if lean and overheating)
I will have to double check my carb diameter, but i do know its a keihin running a 95 main jet. Do you mind outlining your carb specs to help me get a confirmed baseline? My bike came with a cast manifold and a pod filter ( Airbox is long gone ). Thanks for any help and hopefully we get to meet one day. I've never seen another in person.
p.s. couldnt attach pictures, too large i suppose
but this is the one, with factory seat and black side covers and clip-ons instead of full bars now
http://bayarearidersforum.com/forums/showthread.php?t=529987