Spongy front brake - K5.

Help! My 05 pointy had a really spongey front brake, the lever came all the way back to the bar with ease! The bike still stops, but it really doesn't feel nice to ride, I changed the fluid and bled the system which made no difference! I've just changed the master cylinder and this seems to have done nothing?

My next thought is the brake lines, or am I looking past something simple?

[DJ123]

Have you bled the system fully?
What condition are the brake pads/discs in?
On what number is the lever adjustment?

The system is bled fully, I even did the old cable tie around the bar holding the lever in overnight! Pad and discs are fine, recently breezed through the mot. Hopefully it's something simple!

[squirrel_hunter]

Has it just started doing this or is this a progressive thing? Are you using an OEM lever? How have you done the bleeding?

Since you just installed a new master cylinder, it's unlikely that the pressure cup on the master cylinder piston is leaking (that would be an internal bypass leak, not visible), but it's possible.
The only other things that would cause the lever to go to the bar are large amounts of air in the system, a lack of fluid in the reservoir (which would pump air into the line) or an external fluid leak.

I have fixed the issue! My dad says I was bleeding it wrong! My new master cylinder is a radial one off of a 2010 gsxr 1000! Fairly easy to fit and does make a difference!

[Eulaca]

Since you solved the problem, was it air at the banjo that connects to the master cylinder? That's the one that causes me issues when I fit new lines.

Yep that's the one! This new master cylinder has a bleed nipple on it itself, I think I was bleeding in the wrong order