[quote=“Killrob”]For constant size (breathing limited at valves)
bigger bore = significantly more power, more smooth, heavier, larger, more expensive, higher avg. octane requirement, higher max rev, but earlier valve float.
bigger stroke = even less power, less smooth, lighter, smaller, less expensive, lower avg. octane requirement, lower max rev, but later valve float.
At constant size, while not breathing limited at the valves, you take away the effect on power, otherwise things stay the same.
Daffy may correct me when I got something wrong, but that should be most dependencies.[/quote]
Yes of course. I somehow earlier managed to actually understand that when building an engine, increasing bore would be a “better” way to achieve more power from the engine vs increasing the stroke. But as for the power alone, it really does not matter (given that the valve size also scales with the changing bore&stroke ratio) which one do you increase, bore or stroke. The differences between those two are in other areas, engine size, octaine requirement, revs and so on. This has been very educating thread!
Maybe what Daffy said earlier about the cars being taxed by bore in the UK has something to do with it? Anyhow, dont really see what is it that Honda would have proven otherwise with those engines you mentioned…