7. CYLINDER/PISTON Downtown 300i ABS Measure the piston pin O.D. Service Limit: 16.994 mm replace if below Measure the piston O.D. Take measurement at 9mm from the bottom and 90° to the piston pin hole. Service Limit: 72.70mm replace if below Measure the piston-to-piston pin clearance. Service Limit: 0.02mm replace if over CYLINDER INSPECTION Inspect the cylinder bore for wear or damage. Measure the cylinder I.D. at three levels of top, middle and bottom at 90° to the piston pin (in both X and Y directions). Service Limit: 72.70 mm repair or replace if over Measure the cylinder-to-piston clearance. Service Limit: 0.1 mm repair or replace if over The true roundness is the difference between the values measured in X and Y directions. The cylindricity (difference between the values measured at the three levels) is subject to the maximum Top value calculated. Service Limits: True Roundness: Middle 0.05mm repair or replace if over Cylindricity: 0.05 mm repair or replace if Bottom over 7-5