2013 Kawasaki JET SKI Ultra LX Owners Manual - Page 140

138 MAINTENANCE AND ADJUSTMENTS Valve Clearance Valve and valve seats wear decreasing valve clearances, and upsetting valve timing. Spark Plugs Since the engine is water-cooled and is generally operated at a constant throttle opening, cylinder head temperature is relatively stable. For this reason, if the engine is in good condition and properly tuned, it should not be necessary to use a spark plug of a different heat range. Since a spark plug of the wrong heat range can cause extensive engine damage, only the standard spark plug is recommended. Standard Spark Plug Standard Plug: NGK CR9EK Terminal: Plug Gap: Tightening Torque: Threaded terminal 0.7 ∼ 0.8 mm (0.28 ∼ 0.32 in.) 13 N·m (1.3 kgf·m, 115 in·lb) NOTICE If valve clearance is left unadjusted, wear will eventually cause the valves to remain partially open, which lowers performance, burns the valves and valve seats, and may cause serious engine damage. To maintain performance and prevent engine damage, have the valve clearance checked according to the periodic maintenance chart. Valve clearance for each valve should be checked and adjusted in accordance with the Periodic Maintenance Chart. Inspection and adjustment should be done by an authorized Kawasaki dealer. INTAKE 0.15 ∼ 0.24 mm (0.0059 ∼ 0.0094 in.) EXHAUST 0.22 ∼ 0.31 mm (0.0087 ∼ 0.0122 in.) j