The center intake valve is WAY tight. It has a 191 shim. To keep from wasting money and drive/order time, what would be a good guess on a replacement? I'm willing to get two at a time. Would a 175 and a 165 be a good start? Read on for more detail: I got through the Cam Chain replacement. Unfortunately, I did not read the last section of Greyracer's post about checking the Valve clearances BEFORE taking the caps off. I assumed since it was running great when I took it apart, that no valve adjustments would be needed. Anyhoo, the middle intake valve is tighter than a bull-dog bite. The other two and the two exhaust valves are all within specs. I can't even get an .002 (.05mm) in the middle intake valve. So I took the whole darn thing apart again and removed the valve cap/cover. Turns out to be a 191 shim in there form the factory (assuming I'm not reading it upside down). With the number centered at the bottom half of the shim, it's 191. Any help is appreciated. Bronco.