'85 xr200r and a lifan 200cc... Now what?

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So I just got '85 xr200r frame and a lifan 200cc motor, unfortunately I ordered the motor without the carb wiring harness or anything. This is the first time I have really ever f#&% around with dirt bikes and I dont really have a clue what I am doing. I guess I'm just wondering if anyone has advice as far as what I should get as far as a carb or harness etc. The rear sprocket also looks enormous, will that be a problem for the lifan to handle? Is there a general rule as far ratios? Does anyone know where I can find helpful videos for this build (not much that I could find on YouTube) really any helpful tips or tricks would be awesome! Thanks!