I'm wondering if you screwed up when you bypassed the seat relay?
Essentially, here's the path to activate the starter relay:
Starting from ground, you have:
ground----clutch switch----one terminal of start relay---relay coil---other terminal of start relay---yellow----seat relay----yellow-----bulkhead connector----wire to ignition switch "start" connection.
I suppose the start relay could be screwed up internally. Easy to check that. Identify the clutch wire, pull the OPPOSITE wire off and see if the clutch causes it to crank.
Then check with a test lamp to see if the wire you pulled off is hot. It should ONLY be hot with the key in "start." Then go back to the seat relay and see what you bypassed there. As I recall there's two predominately yellow wires that should be jumpered. (One may have a tracer)