So this is somewhat outside the realm of Honda Twins but I'm curious to read what your thoughts are on engine knock ie what can cause it, how to fix it and how these may or may not differ between a 2 and 4 stroke motorcycle engine.
My understanding of engine knock is that there are two different 'classes' of it and they're technically two different phenomena but most people just call it engine knock.
One is 'pre-ignition' which is when something in the combustion chamber is heating up and igniting the fuel prior to the spark (carbon buildup, piston hot spots, etc) OR when the spark itself is occurring too early (timing, etc).
The other is related to pockets of fuel within the combustion chamber igniting after, and separately from, the spark-ignited pocket. Two explosions are occurring and when they collide, a dramatic spike in pressure occurs, giving the pinging sound.
Fixes are pretty clear: no sources of pre-ignition (clean, proper range plug, etc), proper timing of the spark, and fuel that is adequately resistant to improper flame travel,etc.
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