What's with the smoke from the motorcycle exhaust pipe?

It depends on what kind of smoke is emitted.

Black smoke is not conducive to car combustion. Cleaning up the carbon deposit and replacing the spark plug can improve it.

Blue smoke is the performance of engine oil combustion. If the oil gasket is not well sealed, sometimes there will be intermittent oil burning symptoms. You can observe it through the dipstick. If the oil is consumed quickly, this is the problem. You can also put a cloth on the exhaust pipe, then smell it and ask if it is pungent.

Three-way catalytic damage will not occur, but the emission is not up to standard.