How would you know if your quad was a 2 stroke or a 4 stroke?

have a look at the engine if it has a camshaft then its a four stroke, also two strokes have a separate oil bottle for oil.. what make and model is it, google it to find out more..

You can also tell just by listening to it run. 2 cycle has a distinctive higher pitched "Wing-Ding-Ding" noise versus a 4 cycle that has a "Rum-Dum-Dum" noise.

The Carburetor on a 2 cycle would be attached to the crank case, lower part of the engine. 4 Cycle Carbs are usually attached to the top of the engine.