front brake issues (cobra 50jr)

[njkx]

I can't figure out an issue with the front brakes. I replaced the pads and bled the brakes with the syringes specially made for the bike. Everything was fine. bike was ridden for a day and by the end of the day you would have to pull the lever almost all the way to the bars for the brakes to engage. took the bike home and bled the brakes again. everything fine. took out riding again and same issue by the end of the day. :bang:

 

[SHSPVR]

You did say if you are lossen any fliud?, I take it that your doing this on the bike?.
Here a tip take the brake caliper with the line off the bike and any brake line tie down the trick is to get brake line up high as possable that all air move up.
Besure have a small plate of steel or something that thicker then your brake rotor stick beteew the brake pads then re-bleed them.
If this is a opposing pistons know as fixed caliper then one of the pistons is not moving.
Also be sure clean the caliper pin and re-lube them if you have floating caliper.
How ever is possable that the master cylinder failed.

 

[dirt bike dave]

Sounds like the brake is overheating by the end of the day.

If you are using a cheap, low boiling point brake fluid, try using a high quality fluid like Motul 600.

Also, if you overfill the system, it can cause the brakes to drag and overheat.

FWIW, I've had a few bikes where conventional bleeding techniques simply would not get a stubborn bubble out of the brake hose. But in those situations the brakes were weak at the start of the day, too. Taking the entire brake assembly off the bike and hanging it on a wall can absolutely get a bubble out in those situations.

 

[njkx]

thanks. might be overfilled.