[liduno]

It's been a while but when I did my starter there was no need to remove the clutch.

IIRC you can either just take the links off that connect the motor to the gear box and tilt it forward or remove the brake rotor. I read about tilting the motor forward after I did my starter, you may have to remove the seat.

I do have a terrible memory but I definitely didn't remove the clutch.

For the vent you can do a couple different things.
Some drill a hole in the cap and thread in a brass nipple for a hose. I personally didn't want to ruin the dipstick, so I got a ford radiator drain plug [Same thread as dipstick]and drilled it then stuck a hose on it.

No need to plug the port inside, with the vent there wont be any pressure forcing oil through.