Its easy enough to just watch the exhaust valve when you spin the engine over to TDC, after the intake valve closes you will see the exhaust rocker bump just a bit, once you see the exhaust rocker bump, turn it just a hair past that point and set your lash on both valves, then spin the engine over a couple more times to the same point again, to where you see the exhaust rocker bump, and recheck/reset lash. The bump in the exhaust rocker is the compression release on the cam. This is how I always set my lash and it works everytime. I set mine to zero lash on both sides cold, anytime your setting the lash at more than zero lash, your giving up lift when that engine gets up to temp. The .002-.003 lash is whats recommended for theses engines as a pressure washer or generator, not as a racing engine. For a racing engine, you want zero lash when its cold. Set the lash as tight as you can get it but make sure the pushrod can still spin freely with your fingers, and that the lash isn't so tight that its holding a valve open. You can pump the chamber full of air like you were doing a leakdown test and find out if you have the lash set too tight and have a valve open or leaking. I like to do a leakdown test after setting the lash on a newly built or rebuilt engine anyways, if its letting air past the valves after you get the last set, pull the head and lap the valves. I lap the valves anytime the head comes off.
