well try process of elimination, disconnect the slave cylinder from the clutch fork then step on it. if it is still jammed you`ve narrowed it down to the master cylinder or the slave cylinder. if the medal goes to the floor it`s internal. either the clutch or the fork. since it`s in a dune buggy they are really simple to pull the motor 2 guys could have the motor on the ground in about 45 minutes.4 bolts on the bell housing ignition wires fuel line and throttle cable.is about it unless your running some aftermarket stuff like oil coolers or engine cage then you might have a few more items. but they are really simple