The OEM 06-11 Honda Civic clutch master cylinder has an offset chamber that the fluid travels through to get your foot motion to transfer to the clutch. This chamber actually causes the fluid to slow, resulting in a clutch that does not disengage or engage fast enough. This leads to an inconsistent foot-shift movement and in some cases transmission grinds. It's not your fault!
The simple solution is to upgrade to the older generation Honda Civic master cylinder, replacing the OEM FG unit – bundled with a braided stainless line Voila! Problem solved. The new master cylinder also has steel internals while the OEM unit has plastic internals.
If you're seeking smoother shifts that eliminate grinds as you accelerate, likely destroying your transmission, this is the way to go! For an even better shifting experience, try adding Hybrid Racing shifter cables and base bushings.
02-06 Acura RSX (other adjustments to the pedal may be required)
06-11 Honda Civic Si
12-15 Honda Civic Si (other adjustments to the pedal may be required)