2 stroke vs 4 stroke carb

[250sx]

how do you tell them apart? :confused:

[YamaChuck]

I'm no expert but I do believe that with 2 stroke carbs (oil injected motors) you will find a hose barb protruding from somewhere on the carb to accept a hose from the oil pump. 4 stroke carbs do not have these as no mixing of the oil and fuel is required. (Dan, if I'm right I'd like to take what's behind door # 2. And I don't want a gag prize like a pig or a goat !!!!!)

[atc330r]

dan ; it,s in the jets. example 38 mikuni flatslide goes 2 cycle or 4. jet for application 2 or 4 200 to 660 ect.

[dads]

The 2 stroke has larger jets to a low for the thiker fuel mix. That should be the only differance.

[roadx]

The Differences in Two-Stroke and Four-Stroke Carbs
The difference between a two-stroke and four-stroke engine is intake velocity. Two-stroke engines have lower velocity so the needle jet has a half-moon shaped hood protruding into the venturi to produce a low pressure area that aids in drawing the fuel up through the needle jet. Four-stroke carbs need to atomize the fuel more so than a two-stroke carb because so much of the fuel shears along the intake port and separates from the mixture stream. Four-stroke carbs have more jets and finer adjustment screws, plus they usually are equipped with an accelerator pump.

[Mr. Richard]

i think you got the velosity thing backwards a 200cc four stroke engine uses roughly 200cc of air fuel mix every other stroke, where a 200cc two stroke uses alot more cause a two stroke uses the crankcase to charge air to the cylinder and uses twice as much air,,,,, it needs air every stroke

[roadx]

i was talking about the velocity in the carburetor, how many strokes it has, has nothing to do with it. 2strokes and 4strokes carbs are different is all i was stating and a basic reason why.
granted the 2stroke sucks in air every revolution but it is at a lower velocity.

[atc330r]

your right on with the needle jet. i for got about that and i just did a change in a 38

[250sx]

heck, I'm just gonna post a pic of 'em. :confused: :wtf: :doh: