The cam's base circle size doesn't have anything to do with piston to valve clearance. The valve lifts the same amount and with the same timing regardless of the base circle of the cam. Valve to piston clearance has nothing to do with max lift either. At cam's max lift, it's piston is well down the bore, nowhere near the valves. Piston to valve contact can be subtle and it can bend the valve just enough to mess up the valve seal. ((aswracing of the XLFORUM https://www.xlforum.net/forum/buell-motorcycle-forum/buell-motorcycle-top-end/131895-not-exactly-a-conversion#post2810574)) \\ | The cam's base circle size doesn't have anything to do with piston to valve clearance. The valve lifts the same amount and with the same timing regardless of the base circle of the cam. Valve to piston clearance has nothing to do with max lift either. At cam's max lift, it's piston is well down the bore, nowhere near the valves. The piston chases the exhaust valve closed. The intake valve chases the piston down. Piston to valve contact can be subtle and it can bend the valve just enough to mess up the valve seal. ((aswracing of the XLFORUM https://www.xlforum.net/forum/buell-motorcycle-forum/buell-motorcycle-top-end/131895-not-exactly-a-conversion#post2810574)) \\ |