The resistor is there to suppress noise, period. We do not know what rules the various markets had. IMO too much weight is attributed to whether caps had: 5, 7 or 10kOhm resistance. There is a risk people will reason that if some models had 10kOhm resistance, Honda
must have had a
technical reason for it. That's an assumption. Could be, could be not. I have been open for proof for years.
Here's
my assumption. Honda wanted their bikes to be legal in whatever markets they went to. This may have led to differences: some markets got good headlamp reflectors, H4, and what not, other markets demanded inferior but
always on sealed beam headlights and gadget running lights.
Sometimes markets which
themselves did
not have specific demands, nonetheless received the same technics
one particular market demanded. An example of the latter is the cover over the airfilter case the CB500s for most countries in continental Europe had. Germany had legislation on air intake noise and so Honda needed to fit that cover. Other countries like Holland, Italy, Portugal, Austria didn't have that specific ruling, but got the cover
nonetheless. Realise that bikes were produced and shipped in batches. The less different batches, the more economical the production process.
Anyone is free to interprete and connect phenomena in the world around us, but the risk of cognitive dissonans - serving your brain candy - is always there.
If Honda had judged the
variety in the resistance of plugcaps technically meaningful, so
for other reasons than to apply to local ruling, I personally assume Honda would have communicated on this. Yep, another assumption.