Hi folks- I posted while back on differant issues on this GX620- and thanks to all the help it seems to be running great. I don't want to over-rev it but at same time want the max safe rpm. Is their any way I can check rpm without the crank exposed? Not sure what to buy or even how to hook up a electronic tach? Years ago I had a dwell meter..didn't they show rpm's? - my mind is fuzzy on this as I never had reason to check rpms before. Any thoughts on a tach from HF? Thanks again- Gene