2003 Honda VTX 1800, hydraulic clutch goes in and out sporadically. Replaced the fluids and diaphragm. What else could it be?

2003 Honda VTX 1800, hydraulic clutch goes in and out sporadically. Replaced the fluids and diaphragm. What else could it be?

Bleed the clutch again. Make sure there's a solid stream of bubble- free fresh fluid coming out of the clear hose connected to the bleeder valve. If the problem does not go away, replace the master cylinder.

http://tech.bareasschoppers.com/clutch/clutch-bleeding-vtx-1800/

Why can you not give all the symptoms?

Is "goes in and out sporadically" supposed to explain everything?

Air in the system.

"What else could it be?"

Damaged / worn clutch plates.
Damaged / worn clutch springs.
Damaged / worn clutch lifter rod.
Damaged / worn clutch bearing.
Damaged / worn master cylinder piston seal.
Water in the system.