There are a few 1.5s where the crankshaft made an appearance, along with other complete catastrophes, but little is said about them (either because they aren’t there, or because they haven’t been reported). In all of them, there was no warranty (there might be some, but I don’t recall), so it’s understood that it was due to malpractice or similar. The 1.0s that blew up here, I believe almost all of them were covered by the warranty (or almost all), so in terms of reliability, they are similar. And in the USA, without the 1.0, quite a few 1.5s have also gone on a trip, with the famous little problem (not just from Honda) of blocks with a small hole for the coolant that leads to a rather interesting head gasket failure.
The norm with the 1.5 engines is that if they are not tampered with and are well-maintained, they usually don’t cause any problems. Even most of the reprogrammed ones perform well, with some exceptions. There might be an occasional issue, if any, but generally, it’s an engine to maintain and enjoy.
On the other hand, with the 1.0 engines, I’ve seen more problems, both on the forum and in the Telegram group and another WhatsApp group in Catalonia. That doesn’t mean it’s a bad engine, but considering that the belt needs to be changed—a costly operation—and that some have issues, especially if not well-maintained, they are more prone to failure.
It would be good to conduct a more scientific statistical analysis, but for that, a fairly large user base would be needed to vote in a specific reliability thread. I could create one for 2026.
I have the 2021 1.0 restyling with almost 60,000 km, and it will be 5 years old next March. It has never given me any problems, and I haven’t made any modifications except for some aesthetic trivialities. I don’t know if it needs a belt change when it turns 5 years old or not… I hope not because spending that kind of money right now is really inconvenient for me.