Is Motorcycle Piston Slap Caused by the Crankshaft?

[JuliaDella]

Motorcycle piston slap is not caused by the crankshaft. Piston slap refers to the lateral knocking of the piston against the cylinder wall, which is equivalent to a very high-frequency side-to-side oscillation. Piston Slap: Since the new piston and the old cylinder are not originally matched, even if they appear to be in good condition, the excessive clearance between them causes the piston to oscillate within the cylinder under the pressure of high-pressure gases during the engine's power stroke, resulting in knocking against the cylinder wall and producing noise. Piston Pin Slap The main cause of piston pin knocking noise is the excessive clearance between the piston pin and the connecting rod bushing (or the connecting rod bearing itself) or the piston pin bore. During engine operation, the piston pin moves up and down, striking the connecting rod bushing (bearing) or the piston pin bore, generating knocking noises.