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Ten years of adjusting valves wrong, one overheated trail ride in Moab set me straight
I've been rebuilding small engines for fun since I was 19, always setting valve lash with the piston at TDC on the compression stroke. Last fall I took my old DR650 out near Moab and it started pinging so bad I thought the crank was done. Turns out I was checking clearance on the exhaust stroke the whole time, a buddy with a stethoscope and a service manual showed me the mark on the flywheel I'd been ignoring. Has anyone else run a bike or mower for years on a simple mistake that a shop manual would've caught in 10 minutes?
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river_scott1mo ago
Jump right into checking the flywheel marks on everything you own now. I did the same thing on a little Briggs mower for like six years, just cranking the piston to whatever looked like top and shimming it. The thing ran hot and ate spark plugs every summer, figured it was just an old motor being tired. Then I read the actual manual for my Yamaha and saw there's a little T mark and an F mark, and they mean totally different things depending on which stroke you're on. Now I spin the crank until I feel compression push back on my thumb, then I look for that T line and double check the rockers are loose before I even touch a feeler gauge. It's crazy how a 20 minute habit can turn into a decade of bad valve settings without you ever knowing.
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