Spongy brakes!!!!

[Toppie]

I recently purchased a 1986 GSXR400 (GK71F). It has spongy brakes that I want to sort out before I go for a WoF. This is my first bike with hydraulic brakes so I'm not too sure how they should feel but I'm pretty sure they aren't how they should be. I bled both front and back brakes. The back is good now but I can't get the front to come right. There don't seem to be bubbles coming out. I tried holding the lever in overnight then bleeding. It was a bit firmer before I started bleeding but then went soft again.
I noticed that in the first half of the stroke pulling in the brake lever, fluid in pushed into the reservoir. It shoots out if I pull quickly, is this normal or will I have to look deeper into the system? Thanks

[Drew]

The squirt is normal on the older brakes. Most likely cause for the sponge is old lines, they go soft on the iner tube and make it feel soft. New lines are cheap enough, people will wank on about braided lines, but with the technology on that bike, you'll end up with very "wooden" brakes, I'd rather the soft feel given the option.

Servicing the master cylinder will get rid of most of the squirt too, now that I think about it, and again, cheap as hell.

[Toppie]

Cool, thanks for that. I might look into new hoses then. How would I go about servicing the master cylinder?

[erik]

Before you try getting new hoses, take a look at the calliper pistons and the pads and see how far they're moving off the discs when you squeeze and release the lever.
If you can see them moving away from the disc (even just a tiny bit) when the lever is released, it'd be worth pulling the callipers apart, cleaning them, polishing the pistons a bit, then reassembling them lubing the pistons/seals with rubber grease when you do (not regular grease because it'll damage the seals).
The front brakes on my bandit were mushy, the lever almost came all the way back to the bar, doing that was the one thing that helped (I tried replacing the hoses first too). What I think was happening was the seals were sticking to the pistons and pulling them back away from the disc, so most of the lever travel was used just getting the pads to the disc.

[Toppie]

Thanks for that. I just tried it and there is one pad that moves quite far from the disk. I am currently able to pull the lever right back to the bar too. Looks like this might be the problem!