TSB : Piston: Testing and Inspection

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INSPECTION 1. Check the piston for distortion or cracks. NOTE: If the cylinder is bored, an oversized piston must be used. 2. Measure the piston diameter at a point 21 mm from the bottom of the skirt. NOTE: There are two standard-size pistons (No Letter (A) or B). The letter is stamped on the top of the piston . Letters are also stamped on the block as cylinder bore sizes. ^ Piston Diameter: - Standard (New): ^ No Letter (A): 84.980-84.990 mm (3.3457-3.3461 inch) ^ B: 84.970-84.980 mm (3.3453-3.3457 inch) - Service Limit: ^ No Letter (A): 84.970 mm (3.3453 inch) ^ B: 84.960 mm (3.3449 inch) 3. Calculate the difference between cylinder bore diameter and piston diameter. ^ Piston -to-Cylinder Clearance: - Standard (New): 0.020-0.040 mm (0.0008-0.0016 inch) - Service Limit: 0.05 mm (0.002 inch) - If the clearance is near or exceeds the service limit, inspect the piston and cylinder block for excessive wear. ^ Oversize Piston Diameter: - 0.25: 85.230-85.240 mm (3.3555-3.3559 inch) - 0.50: 85.480-85.490 mm (3.3653-3.3657 inch)