2 or 4 stroke refers to the how many strokes is needed for one
engine cycle (oor whatever it is called). In a 2 stroke, one engine
cycle is usually like: piston goes down, air comes in, fuel comes
in, piston goes up, compresses and mixes air and fuel, spark plug
sparks, and conbusts the fuel air mixture pushing the piston down
and propelling the bike forward.
2 stroke --> One *bang* everytime the piston goes up and down
(hence 2 strokes). as in down-up-bang-down-up-bang.
4 stroke -> One bang every 4 strokes. eg.
down-up-down-up-bang-down-up-down-up-bang-etc etc.
2 stroke is less reliable and will generally not last as long as a
4 stroke. But it is easier to repair when comething does go wrong
since it is less complicated. For the same engine size, has more
oomph than a 4 stroke.
4 stroke is more reliable but produces less oomph.
Illustration: Honda NSR 125 is a 2 stroke. Honda CG125 is a 4
stroke.
[This from what i remember from my diploma days many moons ago] -
and i wasn't a good student by any measure!
