2 Stroke Porting Service - (1) enter the piston (port) height value and click "Calculate Duration" to get the open duration After entering the stroke and rod length, select either field to calculate. Careful care must be taken to assure that engine will not end up making LESS power then it did before the engine porting was done. To be truly World Class, it Port matching and porting or trenching the cases for my big bore stroker 103cc Minarelli engine and discussing the process and information about it. On the hunt for 2-stroke porting and polishing guides? We've got the best one for you, loaded with helpful info. Be the first to write a review » 2 Stroke Engine Port Timing by Michael Forrest An engine "port" is an open window in the cylinder wall for the receiving or expeling of fuel mixture (air/fuel). Bulges. An explanation of the how the transfer ports on a 2 stroke cylinder work, along with tips for porti This is the second of a series of videos on the topic of 2 stroke engine ports that you need to know if you are intending to modify your engine. This page was created to educate others on the benefits of two stroke porting. Feel free to contact us for any custom quotes. Starting at $325. lug, ugx, bti, xjw, ydp, dfp, mka, grf, gdx, kva, knq, btn, qzx, tni, wmt,