Brake master cylinder defoaming cover

You may need a vacuum defoaming cover after replacing brake oil to remove bubbles in the brake line.

This is basically for my CB400 front brake master cylinder but it will fit for most of motorcycle brake master cylinder.

Print this as thick wall (more than 3mm) and apply not so tight bolting force.

and you have to prepare a M5-diameter 5mm brass tube fitting, id 4mm vacuum tube, a syringe, a soft rubber seal.