All I did to mine was bore it 1mm as it was very scored and raidous the bottom of the transfer ports on the cylinder sleeve bottom, gut the inside of the expansion chamber and rejet the carb, now it will get the front wheel up in 2nd and 3rd gear with a twist of the trottel, people fit a kawasaki KX 80 ignition system witch makes them rev more,
I wouldnt touch the cylinder head as I am getting detonation on the over run with stock squish, like Greg T says it will get difficult fast.
I am trying to work out if the TS125 cylinder is any better than the TF, the part number is almost the same, TF has a low 1st gear, and slightly different crank caces but the gearbox will interchange