Kawasaki GPX 250 front brakes

[ScreaminGherkin]

If anyone could tell me what size master cylinder one of these bikes should have I'd be a happy man. Not even the kawi dealer could tell me.

[vindy500]

could be in here http://pdftown.com/Kawasaki-GPX250-Service-Manual.html

[Hitcher]

Not even the kawi dealer could tell me.

Try a Kawasaki dealer. He may be able to sort your problem for you. Unless, of course, you find a Kawisaki dealer first.

[FROSTY:Me]

twin or single disk--multi or single pot caliper??

[Squiggles]

twin or single disk--multi or single pot caliper??

Single disk 2 pot from memory

[ScreaminGherkin]

It's a single disk 2 pot sliding caliper.
I have that manual and it hasn't got sizes

I'm asking because after fixing everything that I could find was wrong with my brakes the lever still takes up when it's almost at the bar.
So far I've disassembled the caliper and cleaned it out, visually checked the seals and replaced the pitted caliper piston. Also put in new pads and a new disk.
With the brake hose clamped off the lever comes up hard so if there is still a problem it's in the caliper, but I've started to think it feels like the master cylinder and caliper aren't matched for size since i can't find any more to fix.

Also I'm pretty sure it's not air as it's been bled many times once off the bike.

Any more ideas of what i could try would be apreciated.

[FROSTY:Me]

too wet to check the size on my one

[Max Preload]

With the brake hose clamped off the lever comes up hard so if there is still a problem it's in the caliper, but I've started to think it feels like the master cylinder and caliper aren't matched for size since i can't find any more to fix.

Most likely: dust seals on the caliper pistons are causing the pistons to retract when the lever pressure is released meaning more travel to re-engage the pads with the disc. Did you clean out the grooves they sit in on the caliper housing properly?

Or your hose is bulging under pressure (much less likely).

Where are you clamping the hose and with what - near the top or near the caliper? The latter is my bet. I hope you're not clamping a braided hose because the cores don't like that at all - they are rigid and crushing them will cause them to fail. Rubber is ok, but not with vice grips.

[ScreaminGherkin]

The caliper body was off the bike stripped and cleaned with a brush and soap etc, then rinsed and dried. The seals are sweet i did think the seals were pulling the pistons back further than they should, what can be done about that?
The hose is the genuine non braided item with criped on ends, it's a bit old but it couldn't be the only problem. When clamping it off it was right at the bottom near the caliper.

[Max Preload]

When clamping it off it was right at the bottom near the caliper.

In that case, my money is on the dust seals. To remedy that you need to completely strip the caliper again completely removing the pistons, scraping the corrosion from the dust seal grooves and most likely replacing the dust seals themselves.

Is it a TOKICO caliper? They're famous for it.

[ScreaminGherkin]

Yeah it's a TOKICO caliper.
On that advise I'll get myself a set of seals for the caliper in the new yearand hope that sorts the problem.
Seems it needs new seals anyway because today I went out to the bike and the brakes are full of air again

[Max Preload]

Yeah it's a TOKICO caliper.
On that advise I'll get myself a set of seals for the caliper in the new yearand hope that sorts the problem.
Seems it needs new seals anyway because today I went out to the bike and the brakes are full of air again

You sure it was fully bled?

Tie the lever hard against the twist grip overnight and see if that helps it.

[ScreaminGherkin]

Took the dust seals out and now the lever takes up alot quicker so I'll be off to get all new seals for the caliper when I can.