At the Honda Service Centre I was told that it is time to change my battery on my scooter. I am using an AMCO APX4 on the scooter now. I was looking online for the best battery to replace it with and one suggestion was the Amaron Pro Bike Rider ABR-PR-12APBTX-50. I understand that this is a 5 amp battery. Will replacing a 4 amp with a 5 amp battery cause trouble. All that I know is that a 5 amp battery can last about 20% longer. Shall really appreciate your responses. Thanks.
The short answer to your question is, no, replacing a 5A battery with a 4A battery will not cause trouble as long as fitment and voltage are the same.
That said, automotive batteries are usually measured with two metrics Ah (Amp Hours) and CCA (Cold Cranking Amps), but not strictly amps.
Amp Hours refers to the charge the battery holds, and the measurement is relatively simple. a battery with 5Ah can sustain a 1 amp draw for up to 5 hours with a full charge. The actual life of the battery will vary with time.
Cold Cranking Amps is a measurement of surge current. How much current can the battery provide at one time without being damaged or worse.
In either case, bigger is fine. a 5Ah battery will last longer on a charge and a a 5 CCA battery will be able to provide a larger surge if required. The battery will only provide the current demanded by the load.