Originally Posted by steveg
I don't think they messed it up too bad as I've never heard one popping or expelling unburnt fuel...one of the tricks of 2 stroke tuning is raising the exhaust port so as to evacuate the cylinder sooner and I've read somewhere that tuners were applying that trick to the real deal B1's.
for a powerful and well-performing engine you need ports that have the correct port timing and
the correct ports cross-sections. the scientifical approach to this is called "time-area calculations".
example: while a straw is great for sipping a cocktail, it's just too small
for drinking a pitcher of beer within one minute. you might use two straws, or even more, but you'll soon discover that the cross-section becomes too big
to suck the beer into your mouth. so you have to agree upon a compromise, i.e. "five straws for best drinking performance".
the same thing is valid for engine ports. at low rpm they're too "big" to flow properly, at high rpm they're too "small", throttling the engine. the range between these two rpm is called "power band". regarding the cylinder, the transfer ports have one such power band, and the exhaust port(s) has/have one such power band. the secret for a optimum performance is to combine these two power bands in certain ways.
the blata cylinder is properly engineered, the two power bands are ideally "in tune", resulting in a wide power band.
the chinese cylinders feature the same port dimensions, but different timings. the two power bands are not
"in tune". this means that at low rpm the transfer ports are "okay", but the exhaust ports are too "big", and at high rpm the exhaust ports are "okay", but the transfers are too "small". and there's no way one can eliminate that.
the c1 engine is still able to "produce" a lot of power, but it will never perform as well as a blata cylinder.