Suzuki DF25/DF30 Four Stroke Service Manual, Page 37Get this manual
2-10 PERIODIC MAINTENANCE Adjustment (6) Loosen valve adjusting lock nut 1(7) Turn valve adjusting screw to bring valve clearance to within the specification09900-20803Thickness gauge (8) Tighten valve adjusting lock nut to specified torque while holding valve adjusting screw 2Valve adjusting lock nut11 N.m (1.1 kg-m, 8.0 lbft (9) Recheck valve clearance Reassembly After checking and adjusting all valves, reverse removal procedure for installation Install the cylinder head cover(See page 7-9)