Start with yellow clutch springs.
Get yourself a piece of sheet metal about 3 mm thick put it under the cylinder with a gasket on each side.
Then do some porting widen the exhaust millimeter and a half on each side and bring the floor down so it is at the top of the piston when the Piston is at the bottom of the stroke.
Widen the transfer ports on the intake side 2 mm.
And bring the bottom of the transfer ports flush with the top of the piston at bottom of stroke.
You want your in take transfer Port timing to be approximately 120/122 degrees.
And you want your exhaust Port timing to be 170/272.
With the center of the port at the top Flat 12 mm wide then a flat radius into the corners.
You will need to trim bottom of the piston on the intake side and open up the intake piston port do you have 135 degrees of piston Port timing.
After completing the above you will need to trim off the top of the cylinder so you have a squash of .8 mm 1.1mm at the outer edge of the piston.
Set the ignition timing so that it is 1 mm retarded on the flywheel timing mark check with timing light.
Install app 15 mm sha carb.
Jetting should be in the range of a 68 to a 74.
Notch the slide do lean out the mix at idle look it up!
Sprockets should be in the range of a 12 on the front and a 40 or 42 on the rear or any other comprable confirmation.