+2 on the syringe bleed. You can try to suck it down hill, but the air bubbles just keep going up. I suck out the master cylinder first, then push the fluid in. If you were losing fluid, you can replace it without opening the master, just push it in until you can't put any more in. Takes about 5 min. on the road.
Since you are not losing fluid, you must be sucking in air at some of the seals. The most likely place is at the master cylinder. This usually happens when you let the clutch out. I'd pull it apart and clean the heck out of it.
"Dad, can I get a motorcycle when I grow up?"
"Son, you can't do both"