Okay I am pretty in the dark when it comes to mechanical, but what are the idiots differences between the two and the bonuses of each? Thanks for all your help!

 

Burlock, I doubt you'll do this (only because I don't believe anyone ever consults a reference), but this is the best answer I could give anyone asking your question:

Read "Amazing Voyage" and "Amazing Voyage II," (or was it "Fantastic Voyage" and Fantastic Voyage II?") accessible from the ATV Connection home page ("Tech Tips," I think).

If these articles are no longer "up," maybe someone has a copy they will E-mail you.

Diogenes

 

A 2 stroke has 1 power stroke for every 2 strokes of the pistons, thus it only takes 2 stokes to complete its cycle. What I meen by the powerstroke, is the stroke that the gas and air fill the cylinder, and dentination occurs. forcing the piston down.
a 4 stroke has 1 power stroke for every 4 strokes of the piston, so thus it takes 4 strokes to complete it cycle.


the plus for a four stroke is thats its more user friendly. a four stoke is exactly like you car engine. all you really have to do is add gas and change the oil and filter every once and a while. The four stroke usually give you more low end tork then a two stroke, but have less overall power then a 2 stroke

a 2 stroke engine is more for performance oriented. you can get the same amount Hp from a 2 stroke at half the displacement of a 4 stroke.
matty

 

Two Stroke - Pros - Mods out the wazoo. Sounds cool. Parts easy to find. Simple.

Cons - Can be a pain in the butt in the longrun. Piston changes more common. More likely to have an engine failure.

Four Stroke - Pros - Good Power out of the box. Jump on and Ride. Quieter. Less engine maintnance.

Cons - Mods hard to find. Less easy to work on.

 

does anybody know if its posible to have a two-stroke engine with dry or wet sump lubrication?? the same type that a four-sroke has. if it wont work why?

later
jon

 

The other guys pretty much said it all. 2-strokes have more "punch" and "zip" as compared to 4-strokes which usually have more low end.

Noise isn't a big factor if you are staying in the Sport/utility class. Sport class 2-strokes are a bit higher pitched than the 4-stroke "thumpers".

More mods can be done on a 2-stroke for much less money and bigger overall improvements.

Brian

 

2 Strokes make a powerstroke on every revolution of the crankshaft, 4 strokes require 2 revolutions per powerstroke. 2 strokes are generally lighter, less complicated ( Fewer moving parts ), less expensive to manufacture and make more power for a given engine dispacement. They do require more maintenance, but the maintenance is gennerally simpler than a 4 stroke. The piston, connecting rod and crankshaft are the main moving parts in a 2 stroke. The 4 stroke, in addition, also has valvetrain, a system to drive the valvetrain and the oil lubrication system.
As for wet sump / dry sump, two strokes normally use an oil injection system or oil pre mixed into the fuel for lubrication.
Hope this helps.

 

The bottom line is this. If you are a rookie and
don't know very much about wrenching stay away from 2 strokes. Too much to go wrong for alot of people. I have heard too many stories about needless seizures as a result of improper jetting,
engine modifications, type of oil used, ect..ect...Just my opinion, not a fact.

I love my 2 stroke sport 400, but it was not my first. I started out with cheap jalopy cars that I was constantly working on. Then moved on to dirt bikes (2 and 4 stroke) and now my ATV's.

Just a note: As a four stroke only fires once for
every 2 complete crankshaft revolutions it needs
centrifugal motion to help it through the the non-power stroke. This is where the fly wheel takes over. A fly wheel is a perfectly balanced weight that keeps the engine turning when there is no power from the air/fuel explosion. This is where the famous 4 stroke bottom end comes from. Lots of power down low on the RPM's..That counter weight really keeps things moving while the engine is under heavy lugging.

Keith

 

It won't work on a conventional 2 stroke because the piston pumps the air/fuel/oil mix with both sides of the piston. On the upstoke, it is compressing the mix in the cylinder, but is also drawing fresh mix from the intake into the crankcase under the piston. On the downstroke, the mix in the cylinder fires, producing power, and compressing the mix in the crankcase. The reeds keep the mix from flowing backwards into the carb, so the pressure in the crankcase increases as the piston goes down. Farther down, the exhaust port is exposed (opened) letting the exhaust pressure out, followed shortly by the opening of the intake port, letting the previously compressed mix into the cylinder. Since there is no way I can think of to seperate the crank & rod bearings from the fuel mix, I don't see how it would be possible. The fuel mix would always be contaminating the oil in the crankcase.

 

OK, a single cylinder 2 stroke compared to that of a 4 stroke: The two stroke has twice the powerstrokes as a 4 stroke, but a banshee has 4 times the powerstroke (v2). The 4 stroke: Intake, Compression, Power, and Exust stroke. It has to go through all of those above before moving, while that same 2 stroke goes throught half that much, resulting in better throttle response and more top end speed. I would also like to comment that a pinned 4 stroke is louder than a gunned 2 stroke. Hope this helps.