crankcase porting

[blaster800]

This is especially for Bill O'!!
I've seen on the Net several pics of ported crankcases......
my question is: is this mod useful on a stock displacement engine also with canonic mods? (cyl. porting, perf. exhaust, etc....) My idea is that the porting increases and also redirect the incoming flow but also normally increases the volume of the crankcase that was carefully studied by builders of it. A bigger crankcase means logically a lower primary compression ratio that could be negative on a stock displacement engine, things naturally change on big bore or stroker engines where the displacement is increased and normally porting the crankcase becomes mandatory.
Any idea or advice is welcome!!
Thank you Michele

[Bill O'Neal2]

Re: crankcase porting

Michele,
Proper case porting can benefit the airflow without adding too much case volume. Most hacks, I mean porters, grind too much material from all the wrong places.

Will you see a "noticable seat of the pants gain" with case porting ? I doubt it. But all Yamaha twins can certainly use some major porting work on the clyinders, and some case matching were the ports meet the cases.