spongy brake

[Ade]

Just put my Dr 750 back on the road and went for a long run on her,everything was ok until a came around a bend and 4 cars had stopped because of a cyclist.I grabbed a handful of front brake and the lever came to the handle bar..but I managed to stop before running into the cars..thank god.
I have since fitted a new front s/s braided hose but the brake is still coming to the bar..I have pumped loads of fluid through with a non return self -bleeder,but still the same crappy brake.I have noticed when you pull the lever in,an air bubble rises in the master brake cylinder....any ideas please?

[BigBob]

The seal in your m/cylinder has dried out and is now allowing air past it and also, because it is not sealing, is not pushing the fluid down.
The answer is either to get an OE repair kit which is a fiddly job and not cheap, or go for another m/cylinder from Ebay, preferably a Bandit like several of us have, which will give more pressure and fits straight on (make sure you get the lever with it as it`s different.
Teach you to leave your bike standing and not riding it

[Ade]

Cheers Bob......chuffed with the new trailwings btw!

[BigBob]

[H_Lime]

Myself I wouldn't suggest the bandit pump. Very little lever travel is the pro but the con is a big one, no power, no feel. You will be grabbing a big handful for not much braking in short.
Try a smaller piston, I used one off a ninja 250, the new one. 12mm bore iirc. Although the caliper I have on her is a 4 piston jobbie it displaces a very similar amount of hydraulic fluid compared to the stock system so whats good for it will be good for stock for the same piston stroke from the mc.
Progressive power and just enough travel is the result.

[spendango]

No probs with my front brake and i used a bandit master cylinder ,plenty of stopping power

[nug]

What 4 piston are you using Colum ?

[H_Lime]

Nug, I fitted HE Engineerings billet caliper and bracket. It's based on gileras nordwest I'd say.

viewtopic.php?f=6&t=351&start=350

[nug]

Looks rather lovely mate