Aftermarket forward controls. The rear master cylinder bowl has 2 holes. The rear hole is about 1/8" in diameter. The front hole is very small does the diameter of this hole matter in the overall function and safety of the master cylinder operation

I emailed my mechanic brother who has owned and worked on motorcycles for years. I'll post his answer when he responds.

My brother responded --

Not enough info .... brand of bike, year, modifications that were done, bike or trike, independent master cyl for front and rear or done in tandem ... starting point anyway

Rigid panhead with Jaybrake 5/8" rear m/c for 4 piston rear caliper. sent m/c off for chrome, and the plater put some stuff on the bowl holes ( I guess prevent them from getting plugged up), and the front hole is plugged. The hole is about the size of a hair or the smallest diameter cleaner pin in a welding tip cleaner set. However, because of the depth of the bowl, anything small enough to fit in the hole is too fine and flimsy to withstand the pressure to push it through. Tried solvent, high pressure air; no luck. Thought about boring hole to 1/32 or 1/64", but don't know if enlarging the hole would compromise the function of the m/c.

Rigid panhead with Jaybrake 5/8" rear m/c for 4 piston rear caliper. sent m/c off for chrome, and the plater put some stuff on the bowl holes ( I guess prevent them from getting plugged up), and the front hole is plugged. The hole is about the size of a hair or the smallest diameter cleaner pin in a welding tip cleaner set. However, because of the depth of the bowl, anything small enough to fit in the hole is too fine and flimsy to withstand the pressure to push it through. Tried solvent, high pressure air; no luck. Thought about boring hole to 1/32 or 1/64", but don't know if enlarging the hole would compromise the function of the m/c.

Emailed him with this added info. (Thanks!) Will post again with his reply.

Reply from my brother:

For sure the port needs to be larger. Only X amount of fluid will go thru the port because it still has the diameter of the brake line to limit the fluid flow. There should be some type of seat for the attaching brake line. So as long as that isn't compromised you should be fine. Common sense rules.