Must be a 3W Clone then LOL

Ok, with crankcase transfer 2 strokes (aka - what we use in our "toys") the bore/Stroke ratio is actually very flexible, as has been mentioned, the larger bore / shorter stroke makes a more compact unit with a power band that works well "down low", a smaller bore / long stroke wil give you a higher "top end" torque (think of the Nelson Racing engines).

However, just the bore / stroke ratio os only a small part of the overall equation.

Crankcase compression ratio is also a very large part. this is not just a simple ratio of crankcase volume and overall piston displacement, Rather it is the crankcase volume whn the ports are fully covered versus the remaining piston displacement after that time. This ratio also affects the induction cycle.

True Cylinder compression ratio - same thing. It is not about overall Piston displacement and Combustion chamber volume, (ok - for the purists, swept and unswept volume versus unswept volume) - it is about volume once the ports are fully covered and combustion chamber volume (In fact, most of our engines heve very low "true" compression ratios)

Then of course port timing, desax etc all come into it.

I am lucky to have some VERY good engine modelling software in my system here. it is actually quite interesting to change various factors around and see the final results on expected torque curves. (and yes, Real world data matches the model within less than 8% MOE in most cases when all factors are considered properly). Most of our enignes have a bore/stroke ratio of 1.15 - 1.3, that is where the power curves are best suited for our requirements.

Larger bore also means more reciprocating weight. Shorter stroke means greater acceleration figures on the reciprocating parts, combine those two itmes and you have a need for a MUCH beefier connecting rod, gudgeon pin, wrist bearing and big end bearing at any given speed. (thus adding to reciprocating weight).

For power - keeping all other ratios equal, the oversquare (large bore :small stroke) WILL get you off the line quicker and give you a better low end power. The "Undersquare" (longer stroke : smaller bore) will give you better "legs" in the top end. Close to "Square" will give you the best of both worlds.

Recently I have had cause to model a off the shelf 48mm cylinder with an off the shelf 35mm crank with the intent of using an "off the shelf" cylinder for an engine made from "off the shelf" parts for very respected engine guy who I consider to be a good friend of mine. Even though the cylinder porting was designed for a different stroke, the basic unit still worked very well for the model. It is just a matter of finding the right piston to suit the deck height involved (still working on that side of it).

The best part of this hobby? - ALL products suit someone in it, some of us like to wonder, others like to tinker, others like to get the simple instant gratifaction - we ALL have fun either way, so no matter what the Chinese throw at us (lets face it - right or Wrong, Deserved or not, They are our major suppliers) someone will enjoy the new products.