Originally Posted by Klay
Sometimes there's a little play in the valve rocker arm. When you put the feeler gauge in to check one tappet clearance, the arm will shift a little and give you a false reading. So it's good to have two feeler gauges of the same thickness which you insert at once. Then adjust both valves while both gauges are inserted.
If you do remove the inspection plug to get at the end of the crank, great care must be taken to only very lightly tighten it back up when you close it back up. Or it'll be stuck.
I just turn the rear tire to get the valves closed, not messing with the inspection thing.
A hollow socket and screw tool (valve adjustment tool et al) can make things easier after setting clearances, but I've yet to use the one I bought..
There's a loose rule of: 1 over will be tight and 2 over will not fit.
I've set the valves on an 1150 more times than I can count and found that it can actually be quicker using a guage that is 1 or 2 over rather than trying to get that 'perfect feel/drag' with the correct size gauge.
Whatever works, works...