ORIGINAL: da Rock
4strokes:
are appreciably heavier for the same displacement,
are significantly more complex so they also
cost more,
require more maintenance,
and produce less power
2strokes:
are lighter
simpler
less expensive
require little maintenance
and produce more power
When considering the weight of engines, remember that because of noise, it is impractical to operate engines without mufflers.
As an example, a typical two-stroke engine such as the OS46AX weighs 17.2 oz WITH standard muffler whereas a four-stroke engine such as the Saito 82a weighs 17.6 oz WITH the standard muffler. You get 78% more displacement at a 2% weight penalty by choosing a four-stroke engine. In most applications a Saito 82 will significantly outperform the OS46AX simply because it provides more power at the RPMs we are typically operating our engines at.
/Red B.