Help. I am in the middle of a valve adjustment on my ZRX 1200. It is a "shim style" with the shim on top of the valve. The cam acts on a rocker and then directly on the shim. I have a dilemma. I have seen two methods to position the cams to test the clearances. One involves using the advancer marks, AKA the "shop manual method". I have the manual and I used this method. I also used the "cam lobe up" method. The logic behind the cam lobe up method seems to be that the extra turning of the crank is better/easier because the cams all get measured in exactly the same position. Also you do not need to line up marks because you can see the lobes as you turn the engine. The problem is that the readings are different using the two methods. On two of my lobes they are .002 inches different. On several others they are .001 inches different. This changes the shims needed for the job, and makes me wonder. Which is best, and what should I do? One theory I have is that as long as I am no where near the ramp and there is "at least" adequate clearance that things should be ok. My only argument here is, what if the clearance of .002 inches less is somewhere else on the base circle and this doesn't leave the valve fully seated when the engine is fully warm? The full range of the spec is only .0025 and the shims do not come in fine enough increments to make the lash always stay in spec. Another theory is to test each valve in three places on the base circle and replace shims as needed to maintain at least the minimum spec. The full range of the spec is only .0025 inches and the variance is .002 on two of my base circles on my cam. But man, I feel like I am making a ZRX valve adjustment into a Hubble mirror alignment. Also before you reply. I am a mechanic. I have done many dozens of valve adjustments on cars and a few on motorcycles. I have go/no-go gauges and I have verified all of my readings in every position at least twice, on two separate visits to the engine. I am measuring between the shim and the rocker, per the service manual (not the cam and rocker). I verified my feelers with a mic and verified my mic with a caliper. I have the equipment and the skills to get repeatable readings. I just don't know what to do when the base circle of the cam is not true to the bore. Or there is another phenomena that is occurring you can enlighten me about? And before you worry about me, I have two other motorcycles to ride . I'll be ok if this takes some time to sort out. Help.