i think its a k. The carbs are 0222A's which i believe are from the k model. How can you tell if its an F? Somehting about the kickstarter right? I built the bike from a frame and a motor, so it didnt have too many identifiable parts.
anyway, im looking for a set of larger main jets. I thought of buying a jet reamer, but i'd like to be able to interchange. Its definately braking up at wot above 5k or so, it has a homemade set of pod filters, mac exhaust, and ported intake manifolds.