Hi, first make sure you are doing the bleed the correct way, either use a none return valve or a bottle with the hose submerged in brake fluid to prevent the air returning into the calliper. If you managed to get the lever hard then move on and try this, pump up the brakes until the lever becomes hard then strap a tie wrap or similar around the lever to keep the pressure on and leave it for a while, on return the lever should remain hard, if not look for external leaks check hoses coupling and the callipers. If there's no sign of a external leaks you can assume that the master cylinder piston-valve is leaking. You might get a service kit from here. Hope this helps http://www.ebay.co.uk/bhp/suzuki-front-master-cylinder Edit: l'm assuming its a Suzuki GS850