Front brake lever not firm air trapped ?

[gray]

if you renewed the pads too, maybe they need to bed into the shape of the discs- that can give a spongy feel after a rebuild, that no amount of bleeding will sort.
If you feel you need to bed the brakes in, try a wee run when the roads are quiet and do 5 stops from 50 to 30, then 2 stops from 70 to 30. Not too fierce, mind . Leave a couple of minutes before each stop to let the brakes cool in-between. I think that's what Mintex the brake people suggest.

[Mrg]

if you renewed the pads too, maybe they need to bed into the shape of the discs- that can give a spongy feel after a rebuild, that no amount of bleeding will sort.

I have fitted new pads,pistons and seals
Have got to the point of just riding to find how the brake feels a little more work to do and check over everything I've done then my first time out for me and my bike in 25 years.
Again thanks everyone for the great help will get back to give result of ride.

[deka]

back bleeding works best for me just pumping fluid from on calliper very slowly until you think it is up to the splitter and then do the other calliper until you are filling the reservoir then pump to get pressure into the system. Any air and tie the leaver overnight as suggested

[Mathh]

Don't forget the angle of the handle bar and the banjo/bolt on the m/c. Your calipers and splitter can be air free but there can still be air trapped in that banjo/bolt if that is on the highest point of your brake system. Take a rag, squeeze the brake handle and quickly loosen and tighten the banjo bolt to release any air in there. If necessary turn the handle bar to the other side.

[Mrg]

I checked the front brake to find nothing there at all lever went all the way to the bar with no resistance give it a few pumps and it was back again left it for 12 hours same issue no way am I going to ride while it's doing that will have a go at bleeding the master at the weekend also now have a short blanking bolt so I can test the master on its own hopefully will get this issue sorted.

[Mrg]

Blanked of the master and bleed it on its own and still couldn't get any pressure would explain why nothing worked so much for my new master cylinder

[kev edwards]

You may have a foreign body inside the master cylinder or a problem with the seal, strip it down clean and inspect You may just cure it.

[BAFF1960]

There's only 2 mechanical reasons to stop a brake bleeding being successful, incorrect assembly or a defective part. Unless you've got an anti-dive system linked in its a simple system. If you have consistent problems the just follow a logical inspection route to identify the issue.
As stated before I back bleed via the bleed nipples ( aircraft trick ) so the air is always going up. Doing this I've never had a problem.

[gray]

At the bottom of the master cylinder fluid chamber there are 2 holes - 1 larger 2mm-ish and 1 tiny one. If the tiny one is blocked that's maybe your problem , preventing air bubbles from venting . Use a single wire bristle from a wire brush to check it

[Mrg]

Pull it apart cleaned out and rebuilt this is not an original master just one of those £30 eBay jobs to be honest I think it's shot fluid went a light shade of black and had constant bubbles when it was just the master bleeding think I've worn it out just trying to bleed it.

[BAFF1960]

I wouldn't recommend cheap pattern ( possibly nasty ) primary braking components, I'd rather go with an original / second hand Kawasaki part and service it or even adapting another models unit to suit.

[gray]

looks like GPZ 900 pattern. Try John Browse for a genuine second hand one , then either fit a master cylinder rebuild kit yourself for peace of mind or send it to that company who rebuild master cylinders ( they advertise in Classic Motorcycle Mechanics) who will clean, paint and rebuild it . Might be £100+ , but for brakes that's money well spent. They made a good job of my master cylinder