Hi.I am checking/adjusting the valve clearances on my 1978 cb550. When measuring the gap between the valve stem and and adjustment screw, the feeler gauge, coming in at an angle , forms an arc creating a bit of drag. I am finding this confusing when trying to assess the measurement. For example, it doesn't feel very different on #4 cylinder intake using a 0.05mm or 0.10mm feeler blade.I know it's meant to be .05mm.Is there a knack or trick to it ? maybe bending the blade to an angle? Any advise appreciated.Mike.