CL125 Twin Gearing

question being: what are you guys with small displacement bikes running for gearing? I'm in the process of dialing in a 1967 125 twin to my liking. I'm still working on jetting the pe24 & simultaneously changed the front cog from a 15 to a 16 & it won't accelerate passed 60 or so in 4th gear. Turning maybe 8000rpm at that speed. Does she not have the horse pressure to pull beyond that? The rear gear is a 42. The head has been pulled, valves lapped, new seals, ported, honed cylinder within spec, rings looked good. I appreciate input from personal experience. I've never messed with anything this old or with this displacement in a 4 stroke. Future plans include cr80 inverted forks lowered with disc brake, upper rear shock mounts moved forward with vintage coil overs, knobbies & a few other bar/seat mods. Thanks

Go back to the 15 tooth countershaft sprocket and maybe even a 14 if you can find it.
The little 125 likes / needs to really wind up the revs to get to top speed - like 10,000 rpm. If you can find an old race kit with the special springs and whatnot, they turned them up to 13,000 rpm - not bad for (almost) 50 years ago.
The later K3 twin carb head should fit if you can find one; I've been looking on and off for 3 years for one and it really makes the little beastie come alive. The later 5 speed may fit your cases, but I wouldn't have any idea on how much work it is to get the damned thing in there.
Because they have a siamesed bore, you can't do much in the way of a big bore kit but probably CA95 pistons (150cc) and maybe CA / CB/CL160 pistons (161cc) would work to give you a bit more displacement but please check your measurements first. They all have the same piston pin diameter and stroke but the compression height may vary a bit, so you have to check valve clearance and whatnot.
Fun little bikes, the Honda 125 twins. My buddy had a 1967 CD125 and us two dumb kids rode all over Southern Ontario on it in 1967.
Pat