I bought dirt bike for husband! is 2005 yamaha yz250 a 2-stroke or 4-stroke? i'm not sure if it's yz250 or yz250f now that i'm to get posted i'm not sure of year. sleeve around cable say nov 2005

Congrats on the purchase! easy way to tell look at the exhaust pipe. if it is just a thin tube that is tight to the engine and goes right to the muffler it is a 4 stroke (250f). the four strokes have a square-ish head. Deep/bass-y engine sound. If you have a large (probably black) exhaust pipe with a large bulge in it (5-6" diameter) that wraps around the front of the frame, its a 2-stroke. They have a more round cylinder head. Beautiful pingy sound and a little smokey at start up. DON'T FORGET TO MIX YOUR GAS!!! there should be a serial number sticker at the very front of the frame (behind the number plate where your triple clamp/handlebars connect) Probably on the left side. Hope it helps! rate please :)