I went through the same situation when I did my rebuild on my 88 250 last spring.....one of the valves had the very tip broken off and I was able to drill and tap to a piece of 6mm bolt that I threaded into the valve & ground it to the proper length. It worked but I'll probably look for a new set as the gears and the track for the center valve are worn. But, they are working great for now. left and right pn# 12005-1099 & 12005-1100