1999 Polaris SLH, SLTH, SLX, SLTX, PRO785 Factory Service Manual, Page 65Get this manual
MAINTENANCEfTUNE UP Troubleshooting Piston Damage
Symptoms: Hole in piston Water in carburetors or fuel Lean fuel mixture (see lean condition troubleshooting) Detonation from incorrect ignition timing, poor quality fuel, modified cylinder heads, excessive carbon buildup, etcIncorrect spark plug Overheated engine Flywheel key sheared, keyway damaged, flywheel damage Crankshaft out of index Symptoms: Eroded piston (exhaust edge of crown) or scuffed piston Lean fuel mixture (see lean condition troubleshooting) Detonation from incorrect ignition timing, poor quality fuel, modified cylinder heads, excessive carbon buildup, etcEngine overheating (inspect cooling system) Crankshaft out of index (see engine section) Flywheel key sheared