I'm no racer either but I've adjusted the shiftlight so that it lights when engine hits 12500 rpm... There's still nice 3000 rpm overhead left if needed [8D]. Usually I shift to second well before the limiter, somewhere near 13500 so next gear drops nicely near the peak of the powerband.
Btw, just tested that 636 takes indicated 115 km/h in 1st gear before the rev limiter kicks in. Second is good for indicated 160 km/h...
I think the gearing of first two gears is pretty much spot on for most situations, especially in street.
For example in cbr 600 rr 1st gear goes up to indicated 125 km/h and second to ind. 170 km/h. My friend who owns the bike and is much faster track rider than I has felt that the gearing in 1st, 2nd and 3rd gears might be a touch too tall in Honda.
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7,62mm. One size fits all.