Hey Pattojnr,
You are right regarding the timing. I would be interested exactly what did you do and how did you know how much to change the ports in the sleeve?
Regarding the Crank I wouldn’t touch it, because the last action in the production process is balancing. So if you modifying it you can ruin the balance of the crank. The result can be shorter life time of the bearings or worse breaking of the bearings.
But anyway always when you tune an engine (assuming you are doing it right) you shorten its life time because you expose it to greater stress.
The power of engines in these days is way over what materials can handle! In the future the manufacturers don’t have many options to get more power. If they increase power with existing materials the life times of engines will be shorter and shorter. So the main point is to focus on stronger materials that are able to withstand more stress. But this will mean more costly engines for us.
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