Not sure how close the seat is, normally I can just loosen the engine mount and rock the engine away from the seat and have enough room to pull the clutch off.
I cut a hole with a holesaw just large enough for a 1/2" socket to fit through in the side of the seat that I can reach through with an impact and extension. To get the clutch off, you may need to loosen the motor mount butterfly clamps and tilt the engine out, depending on how close the seat is to the clutch. You're going to have to at least loosen the butterfly clamps to get the chain off and re-adjust slack after you make the change anyhow.
Remember to allow enough slack in your throttle cable and Mychron leads so that you don't damage anything when changing clutches in a hurry at the track.