According to my manual for taking out the shim, you have to use an air compressor to blow the air in the shim hole, then use a magnetic pen to pick up the shim and slide it out. However, I couldn't do it that way so I had to remove the cams after measuring the valve clearance. To measure the clearance, I used the regular valve shim caliper that has a whole bunch of metal leafs with specific thickness. Slide each one in between the cam and shim until the perfect leaf fit. That's how I got the measurement. I used the metric caliper so there's no need for conversion.