spongy brake

Questions regarding the DR750

spongy brake

Postby Ade » Sat May 09, 2015 6:26 pm

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 :x 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?
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Re: spongy brake

Postby BigBob » Sat May 09, 2015 8:23 pm

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 ;)
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Re: spongy brake

Postby Ade » Sat May 09, 2015 8:33 pm

Cheers Bob......chuffed with the new trailwings btw! :)
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Re: spongy brake

Postby BigBob » Sat May 09, 2015 9:51 pm

:tup:
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Re: spongy brake

Postby H_Lime » Sun May 10, 2015 8:14 am

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.
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Re: spongy brake

Postby spendango » Sun May 10, 2015 3:16 pm

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

Postby nug » Mon May 11, 2015 7:56 am

What 4 piston are you using Colum ?
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Re: spongy brake

Postby H_Lime » Sat May 16, 2015 8:04 am

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

Postby nug » Sun May 17, 2015 4:45 pm

Looks rather lovely mate :tup:
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