I had a GP100 and it was pretty rapid for its size.Never had a CB125, but I reckon my Suzuki GT125 Stinger twin would have eaten it up, in a straight line, at least!
Larger main jet, polished ports, micron exhaust, up geared. Would do 80 on flat.
By gearing and revs not the 85 on speedo or 90 down telegraph hill.
