had 92 rm 250 engine bored 69mm stroked 80 thou. off set pin. has 80 thou spacer plate. when piston b.d.c ports probally 5mm higher can this be changed. piston is 1.2mm below t.d.c. have 2.3 mm squish. going to have cylinder or spacer cut for deck height. + head cut to close squish to 1.2 mm. but not sure about ports. did some math + cauculated this to be like 272 cc. not sure i am right but this what i figured. 69x69x3.1416 x73strokedevided4000 272.6. i also figured 22cc c.v. would be correct compression for alchol use saftly. any input thanks. this engine will be run in micro sprint.
