TIPS FOR UP CYLINDER BORE

      When you change the capacity of the cylinder of the engine, the are many factors that must be considered. Like: porting, compression ratio, carburetor jetting, silencer, and ignition timing. The size and duration ported exhaust and intake open, compared with engine capacity and RPM. When the liner wall and crushed to include a larger piston, realize that the transfer port will turn the corner, and ported exhaust will shrink?And when you just do this, then the torque at low RPM will be abundant, and energy in round over weakening. 

      Changing the angle of the engine must done, and the ratio of the dome with a squish must be reset to adjust the diameter of the new piston. Piston greater mean turbulence harder, so the squish must be narrowed. Dome volume combustion chamber must be regulated to adjust the capacity of the new engine. Or the engine will only feel 'stop' at high speed, flat run away. Even worse wold arise detonation.