What type of valves did he price you? I don't understand why all 8 valves would be bent and the bike still run properly, I bent one of the exhaust valves on my old YFZ and it ran like crap.
That being said $86 a piece for valves isn't bad if their titanium, my CV4 Xceldyne's I run in my race quad cost me around that with my discount. If you can get me specs on the valves I can see what I can do about getting you a better price but can't promise anything.