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The ckp sensor is located on the left side of the crankcase in front of the engine just to the left of the oil filter, it's held in place with a hex socket screw, remove the screw and the ckp sensor pulls right out of the crankcase, you'll need to feed the wires from the new sensor to the right side cover below the seat to connect it.
To replace the exhaust gasket, you'll need to remove both mufflers, and pipes downstream of the rear head pipe on both sides of the bike, loosen the bolts that hold the starter to the back of the inner primary cover and remove the triangular brace for the exhaust pipe that goes to the left of the bike to get enough clearance to ease back the rear head pipe, loosen the clamp that connects the rear and front headpipe, remove the nuts that hold the headpipe to the cylinder head and ease the headpipe back to remove it.