8. CYLINDER/PISTON AGILITY 50 SERVICE INFORMATION.......................8-1 PISTON REMOVAL................................. 8-2 TROUBLESHOOTING..............................8-1 PISTON INSTALLATION........................ 8-6 CYLINDER REMOVAL ...........................8-2 CYLINDER INSTALLATION ................. 8-6 SERVICE INFORMATION GENERAL INSTRUCTIONS · The cylinder and piston can be serviced with the engine installed in the frame. · After disassembly, clean the removed parts and dry them with compressed air before inspection. SPECIFICATIONS Item Standard (mm) Service Limit (mm) I.D. 50.00-50.01 Warpage 0.05 Cylinder Cylindricity 0.05 True roundness 0.05 Ring-to- Top 0.015-0.050 0.09 clearance Second 0.015-0.050 0.09 Top 0.08-0.20 0.45 Piston, Ring end gap Second 0.05-0.20 0.45 piston ring Oil side rail 0.20-0.70 Piston O.D. 49.97-49.990 49.9 Piston O.D. measuring 9mm from bottom of skirt Piston-to-cylinder clearance 0.010-0.040 0.1 Piston pin hole I.D. 13.002-13.008 13.04 Piston pin O.D 12.994-13.000 12.96 Piston-to-piston pin clearance 0.002-0.014 Connecting rod small end I.D. bore 13.016-13.034 13.06 TROUBLESHOOTING · When hard starting or poor performance at low speed occurs, check the crankcase breather for white smoke. If white smoke is found, it means that the piston rings are worn, stuck or broken. Compression too low or uneven compression Excessive smoke from exhaust muffler · Worn, stuck or broken piston rings · Worn or damaged piston rings · Worn or damaged cylinder and piston · Worn or damaged cylinder and piston Compression too high Abnormal noisy piston · Excessive carbon build-up in combustion · Worn cylinder, piston and piston rings chamber or on piston head · Worn piston pin hole and piston pin 8-1